Author: Chris Higgins

Using Grodan for Lettuce and Herbs

Using Grodan for Lettuce and Herbs 

In recent years there has been
a worldwide increase
in the consumption
of lettuce and fresh herbs. Naturally this has led to an increase in production.  More and more growers are now opting to use GRODAN
as their substrate.
The benefits of
using GRODAN in the production process are:
  • It is an
    inert and hygienic substrate
  • The speed and
    uniformity of germination and growth.
  • There is
    sufficient substrate volume to propagate to the
    desired plant size.
  • Once it is
    placed in the gutter or raft system the
    propagation blocks provide further stability.
Inert and clean
GRODAN stone wool
is an inert and hygienic
substrate, so it provides your crop with a clean,
disease free start. Furthermore, stone wool retains its structure throughout the cultivation
cycle. Filters remain clean and free from blockages, cleaning between crops is
easier and more importantly, faster, allowing less downtime between crops. The
fact that it is also inert means that all applied nutrients and
water are directly available for the growing crop. The combination of faster turnaround
and faster growth adds to the possibility of extra cultivation cycles during
the year.
Uniformity and speed of germination and growth
One of the most critical
stages of cultivation is germination. Seed holes cut into the stone wool plugs provide
the perfect air/water ratio around the seed which facilitates a high
germination percentage. More importantly, as the stone wool substrate is
uniformly saturated, each seed has the same germination environment, which provides uniformity in
emergence and initial growth. The speed and uniformity of growth which
follows results in a higher quality end product. It also provides a crucial opportunity
for additional cultivation cycles during the year.
Substrate volume to propagate the desired plant size
There are two distinguishable
stages in the production process; propagation and final production.
With the propagation of lettuce, a favorable microclimate is required. This is partly achieved
by retaining a high plant density. 
In GRODAN trials, we have seen that when the propagation period
is extended (21-24 days), the microclimate created results in more speed in
final production. Also, as larger plants are used, the production cycle is shortened,
once again providing an opportunity for additional cultivation cycles during
the year.
In order to extend the propagation
period you also require a larger substrate volume (i.e. AO
36/40 or MM40/40). This larger volume allows more root growth and
more stability.  Crucially, it also
allows irrigation to be managed. Often in propagation, too much water is given.
This results in weaker plants with greater susceptibility to disease.
Having the right irrigation strategy with the right substrate volume will give
you the possibility to be critical to the moment of irrigation. Having a precise irrigation
strategy will also retain the roots within the plug and therefore result in less
damage during transplanting.
To improve the irrigation strategy, we would suggest that you weigh
the blocks or AO sheets to decide if irrigation is needed (table 1).
Table 1. Indicative weights to irrigate the
blocks or AO sheets.
Grodan product
Approximate substrate volume
Indicative weight to base irrigation on (±60% WC)
MM 40/40
64 ml per block
40 gram per block
AO 36/40
40 ml per plug
3926ml per sheet
24 gram per plug
2.4 kg per sheet

Stability during use in gutter or raft system

Depending on the production system
which is used, the
GRODAN propagation component provides a certain degree of stability. For plants in
gutter systems, suitable products are MM blocks or the AX
plugs (figure 1). For plants in a raft system an AO plug is recommended, as its tapered
base makes planting
into the raft faster.
Figure 1. Left picture showing Grodan AX  plugs with basil seedlings, middle Grodan MM
blocks with lettuce during propagation stage, right picture showing Grodan AO
plug.
Conclusion
GRODAN stone wool
will give you an inert, clean substrate which provides fast, uniform
germination and growth. Whether you have a raft or gutter system, we have a plug or block that
will fit your needs.

For more information
contact Hort Americas at 469-532-2383 or customerservice@hortamericas.com 

Visit our corporate website at https://hortamericas.com

Improving research in controlled environment facilities

University researchers, extension specialists, industry
representatives and USDA officials are working together to improve how research
is conducted in controlled environment structures, including greenhouses.

By David Kuack
North Central Extension & Research Activity–101
(NCERA-101) is a committee of the USDA
organized to help plant scientists understand how to use controlled environment
technology. The committee initially began in 1969 when plant scientists in the
American Society for Horticultural Science began to discuss how to effectively
use growth chambers to ensure consistent and comparable growth data. When the
committee was organized in 1976 as the North Central Research-101 (NCR-101)
committee, the group expanded to include all plant science researchers and
began encouraging private industry groups to participate.

NCERA-101 was organized to help plant scientists understand
how to use controlled environment technology.
Photo courtesy of University of Alaska

NCERA-101 now has
over 160 members from 102 institutions and industries. There are even members
from outside the United States.

“NCERA-101 is a project with USDA,” said University of
Alaska horticulture professor Meriam Karlsson, who is the chairperson of the
committee. “USDA has several of these working groups or committees that work on
special topics. This committee is particularly large compared to some of the
others because of the involvement of industry members along with researchers.”
Poster child for
cooperation

Karlsson said the NCERA committee has to apply for
renewal every five years to keep operating and to keep receiving funding from
USDA. The USDA funding is distributed to land grant universities and their
experiment stations.

“The committee is open to industry and non-university
persons working with controlled environment technology appropriate for plant
research and production,” said Karlsson. “That is part of the reason the
committee has become so large. Industry members provide input and support the
work the university and extension personnel are doing. We can also communicate directly
to the industry members what kind of technology is needed in both greenhouses
and growth chambers in order to control the environment.”
Karlsson said USDA officials are very happy with the way
NCERA-101
has been operating with the communication and cooperation that is occurring
between university scientists and industry members.
“USDA officials tell us this is how they would like other
committees to work together on multi-state projects,” she said. “USDA works
with a sizable list of working groups,
including animal sciences, forage, insects and diseases. There is no limit in
regards to the number of members the committee can have, although to keep
focused the group needs to remain manageable. NCERA-101 also collaborates with
similar working groups in Europe and Australia. In two years the meeting will
be international and held in Australia.”
Information sharing

As chairperson, Karlsson prepares an annual report and
the committee holds an annual meeting, which occurred in Alaska earlier this
year.

“During the meeting there is information sharing among
the members,” she said. “Everybody is asked to give station reports and talk
about what they are working on. It primarily has to do with how the researchers
are using controlled environment technology. It could be greenhouses, but much
of the research is being done in growth chambers, phytotrons and biotrons. The
discussions are very specific about how to run the growth chambers and what
kind of variables to measure.”
Karlsson said one of the hot topics of discussion among
the members is lighting and LEDs.
“Right now it’s very confusing as to how to evaluate LEDs,”
she said. “This is one of the committee’s areas of focus—light measurement, how
to provide sufficient light and how to use light. When using artificial lamps
there isn’t a natural spectrum.”
Another topic of discussion has been about humidity and
its effect on plants.
“How do you measure humidity and provide it
consistently?” Karlsson said. “Much of the discussion is related to how to
characterize the environment. The same types of discussions also occur
regarding the instrumentation that is used to measure these variables. The
committee works on developing guidelines for measuring these essential
variables.”
The guidelines developed by the committee can then be
used by scientists worldwide to consistently measure environmental conditions
regardless of where the research is conducted.
“Industry members also discuss the challenges they face
in regards to developing the measuring instrumentation that the scientists are
telling them is needed,” she said. “The scientists want the equipment to
measure a variable with limited influence of other factors.”
New greenhouse
open house

During this year’s NCERA-101 annual meeting, which was hosted
by the University of Alaska Fairbanks, Karlsson had the opportunity to show off
the new teaching and research greenhouse that was recently completed. The
4,500-square-foot Nexus greenhouse consists of an upper and lower level. The
upper level, which was completed in 2012, is used for teaching and
instructional purposes. The lower level, which was finished earlier this year, will
be used for research.

 The new greenhouses at the University of Alaska
are equipped with high pressure sodium lamps.
Photo courtesy of University of Alaska 
The greenhouses are equipped with both blackout and
shade/energy curtains. There is also a Mee fog system which is used to cool the
greenhouses and to increase the humidity.
“During the winter the natural humidity is really low,”
Karlsson said. “During the summer when the temperatures can reach into the 80s,
the fog system keeps the greenhouses cool.”
Karlsson said when the greenhouses were being planned
during 2010-2011 the decision was made to install high pressure sodium lamps.
“At the time the technology for the LEDs was not
developed enough for us to choose them,” she said. “We are doing research with
LEDs because the cost of electricity here is very expensive and LEDs are anticipated
to be more efficient. I expect LEDs will make a big difference for the
commercial greenhouse industry in the state. We are looking at how we can get
enough light from LEDs to substitute for high pressure sodium to promote the
kind of growth we want to have. And we need to determine how plants respond to
different light qualities under our growing conditions.”
Interest in food
crops

Karlsson said there is a lot of interest in many
communities in Alaska about hydroponics and the production of food crops.

University of Alaska researchers are studying the
feasibility of growing a variety of edible crops.

“Alaska is at the end of the supply line so there is a
lot of interest in extending the growing season and even possibly growing
during the winter months,” she said. “We are looking at growing hydroponically and what is the
easiest way to produce leafy greens, lettuce, tomatoes and cucumbers. Even
though Alaska is known for having major natural gas and oil reserves, having an
affordable energy source is one of the obstacles that has to be addressed. Some
communities have access to natural gas, which is almost an unlimited resource.”

Karlsson said because of Alaska’s cold, dark winters,
there is interest in growing hydroponically with vertical shelf systems.
“There is also a lot of interest in greenhouses and high
tunnels,” she said. “Alaska is a big state. South of Anchorage on the Kenai
peninsula, high tunnels are used to start the season earlier in the spring and
to extend fall production. The climate is more moderate there. As you go
further north, it doesn’t make sense to put up a high tunnel. Greenhouses would
be a better choice. Even during the summer when there is plenty of light, some
heat would be needed in the greenhouses to maintain the warmer temperatures the
crops would need.”

For more:
Meriam Karlsson, University of Alaska Fairbanks, (907) 474-7005;
mgkarlsson@alaska.edu.

David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.

Visit our corporate website at https://hortamericas.com

Creating the ideal environment for orchid production

Green Circle Growers continually works to improve and
refine the production environment for the orchids in its “Just Add Ice Orchids”
program.

By David Kuack
Green Circle Growers in Oberlin, Ohio, is serious about
producing orchids. It grows 6.5 million phalaenopsis orchids annually in 25
acres of Venlo-style glass greenhouses built specifically for orchid
production.



Green Circle Growers’ goal is to produce the most uniform,
highest quality orchids.
 

“We have a high efficiency production system,” said
grower manager Frank Paul. “Everything is standardized. Everything follows a
certain path through our facility.”
Paul said orchids are very manipulative. The greenhouses
are divided into vegetative areas and generative areas. All of the vegetative
areas are at 83ºF
and 65 percent relative humidity. The greenhouses are equipped with a high
pressure fog system for humidity control and also receive supplemental carbon
dioxide.
“Throughout the different vegetative stages of orchid
production the light levels are slowly increased, but the temperature and
humidity remain fairly similar,” he said. “The young plant stage is an average
26 weeks. After the young plant stage, the mature plants in 5-inch pots remain
in a vegetative stage for about 24 weeks before being moved into a cooling
stage.
“Only when the plants are large enough to produce good
quality flower spikes are they moved into the cooling stage. During the cooling
stage, the temperatures are lowered to an average of 70ºF along with an
increase in light levels that initiates the flower spikes. From flower
initiation to shipping is 19 weeks.”
In order to produce plants as uniform as possible, a set
of grading steps was implemented. A camera is used for objective grade
determination.
“Whatever plants are not up to size receive a longer
period of time in the vegetative stage,” Paul said. “Once plants reach the size
that is necessary to produce good quality flower spikes they are moved to the
generative or cooling stage. Our goal is to make the output as uniform as
possible at the highest possible quality.”
Creating the
“perfect” environment

Paul said being able to grow a quality orchid comes down
to the ability to modify the climate conditions to create the perfect growth
environment.

“It is very focused on climate control and climate
control software,” he said. “The first 26 weeks in the young plant stage is by
far the most critical stage. The most important thing is to maintain a stable
growth speed along the way. Disturbances in the growing environment at this
stage can result in a significantly higher percentage of disease and losses.
Those problems can start to a small extent in the young plant stage. Typically
the chances for problems increase once the plants move to the mature vegetative
stage. The problems can be major depending on the level of disturbance
experienced by the plants. That’s why it is so important to keep things stable
at all times. Disturbances include fluctuations in temperature, moisture
levels, soluble salts and pH.”

Grower manager Frank Paul said being able
to grow a quality orchid comes down to the
ability to modify the climate conditions to
create the perfect growth environment.

The greenhouses are equipped with several different
curtains, including indoor and outdoor shade curtains. The outside curtains
help keep the heat out during the summer.

One indoor curtain is primarily for energy savings. The
houses also are equipped with Harmony light diffusion/energy saving curtains.
This white polyester screen brings more light to the plants from all directions
helping to stimulate growth. At night it acts as heat retention curtain.
“Orchids are natural shade plants,” Paul said. “They use
fairly low light levels. They don’t like direct sunlight at all so that is why
we are using the Harmony curtains during the day to diffuse the light.”
All of the greenhouses are equipped with high pressure
sodium lamps. In the generative stage areas of the greenhouses the plants need
higher light levels. The greenhouse curtains are open several hours during the
day in those houses. In the vegetative stage greenhouses the Harmony curtains are usually closed 99 percent of the time.
The HID lamps are used primarily during the winter.
“Phalaenopsis are not daylight sensitive, but we try to
maintain a 14-hour day all of the time,” Paul said. “The lamps help to maintain
stable growth at all times. We usually start using them during the second half
of August and run them for one to three hours every morning, gradually
increasing the operating time toward the shortest natural day in December.”
Sweating the small
stuff

Paul said the greenhouses are very open and equipped with
open-structured benches which allow for greater airflow.

“In order to maintain 70ºF during the summer three large chillers have been
installed that produce 38ºF
water,” he said. “The water is pumped to climate optimizers which help to cool
down the air during the warmer months. The climate optimizers located under the
benches are used for both heating and cooling. They can switch back and forth.
The optimizers over the top of the benches are used for cooling only. The
optimizers are basically large air conditioning units through which either cold
or hot water is pumped. The cooled or heated air is sucked through a radiator
and blown through tubes which distribute the air.”

Climate optimizers located under the benches are used for
both heating and cooling. The optimizers are like large air
conditioning units through which either cold or hot water
is pumped.

Paul said orchids are very sensitive to high salt levels.
The soluble salts (electrical conductivity) and pH of the water are monitored
daily.
“We do frequent soil and water sample analyses,” he said.
“We have an in-house water lab that does weekly analyses of specific elements
in the water.”
Rain water is the irrigation water source and is treated
with chlorine dioxide.
“Rain water is relatively clean, but it is important to
keep the water pipes and irrigation lines clean,” Paul said. “Irrigation water
is the primary source of spreading infection. Chlorine dioxide helps to
suppress pathogens from spreading.”
The greenhouses were initially equipped with boom
irrigation, but Paul has been looking at potentially installing an overhead
sprinkler system.
“The booms are spray bars that move over the tops of the
plants up to 10 times during an irrigation cycle,” he said. “The overhead sprinkler
system is a permanent irrigation line, which provides a steadier flow of water
falling on the plants. Overhead irrigation is more constant and allows the
water to flow down through the growing medium and along the sides of the pot
for better leaching. The medium for the finished plants is a mixture of bark
chips and sphagnum peat. Foam is added to the medium in the young plant stage
for the first 26 weeks. All of the drain water is collected into ponds and
reused on other plants in our facilities. It is not reused on the orchids.”
Paul said growing issues with orchids are not seasonally
related. Diseases are the biggest challenge.
“Pseudomonas and Fusarium are very common diseases in
orchid production,” he said. “Pseudomonas is a bacterial disease associated
with the foliage. Fusarium is a fungus that attacks the crown of the plant.
Unstable growth makes the plants more susceptible to these diseases. If the
plants are kept wet too long that makes them more susceptible. Phalaenopsis has
to be dried out before going into the night.”
Paul said the best defense against everything for orchids
is maintaining a healthy plant.
“Creating the ideal conditions for a healthy growing
plant is our main focus,” he said. “Once you get away from that, diseases and
insects become more of a problem. It’s all related to keeping the plants
growing healthy and active at a steady pace all of the time.”
Expanding the Just Add Ice program

The main crop in Green Circle Growers’ “Just Add Ice Orchids”
program
is 5-inch phalaenopsis orchids. As the Just Add Ice name implies, consumers are
directed to use three ice cubes per week to water the plants.

The company has expanded the program with mini-orchids,
anthuriums, bonzi, bromeliads and Pachira
aquatica, called the money tree.
“The mini-orchids account for 10-15 percent of our orchid
sales,” said grower manager Frank Paul. “We are looking to grow the
mini-orchids to 30-40 percent of the program’s sales in the next couple years.
The mini-orchids are also phalaenopsis species.”
The mini-orchids follow similar steps to the other
phalaenopsis, but conditions slightly vary. Because the growing medium is
different for the mini-orchids, there are different requirements regarding
fertilization, irrigation and the cooling process for spike initiation.
Paul said the greenhouses being used for orchid
production are also suitable for anthuriums and bromeliads. Although these
tropical plants finish in about the same time (10-11 months) for the mature
plant stage as the phalaenopsis orchids, they do not follow the same production
schedule. He said the greenhouses designated for phalaenopsis are only used for
orchids.
“The anthurium and bromeliad crops could be grown in the
orchid greenhouses,” he said. “However, because each of these crops requires
its own specific climate conditions and its own specific climate conditions and
has a unique production schedule, we dedicate specific greenhouses to one crop
only.”

For more: Green Circle Growers, (440) 775-1411; fpaul@greencirclegrowers.com; http://www.greencirclegrowers.com; http://www.justaddiceorchids.com.

David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.

Visit our corporate website at https://hortamericas.com

New online tool enables growers to diagnose strawberry problems

Scientists and IT developers at North Carolina State University are creating an online diagnostic tool that will assist strawberry growers in determining and resolving crop-related issues.

Starting June 30 strawberry growers will have a new online diagnostic tool to help them identify problems they may encounter with their crops. As part of the National Strawberry Sustainability Initiative grant, which is funded by the Walmart Foundation, a group of North Carolina State University scientists and extension IT developers
are creating a web-based interactive diagnostic key for growers. It will have application to both outdoor- and indoor-produced strawberries throughout the United States.

The key will be accessible through users’ computers, tablets and smart phones. It will be available through the North Carolina Cooperative Extension Strawberry Growers Information website.

A holistic approach

Brian Whipker, professor of floriculture–research and extension, who heads up the project, said the key
is based on attributes.

“There are 21 insect pests, 26 diseases, 14 nutritional disorders and 26 physiological disorders in the key,” Whipker said. “It covers the primary sources of problems. The herbicide damage probably won’t have application to greenhouse production, but almost everything else, including the diseases, nutritional disorders, and most of the physiological disorders and insects will apply.
“When users log onto the website there is a filter on the left side of the homepage that is based on four categories (insect, disease, nutritional and disorder) that they can sort by. The term physiological was replaced by the word disorder.”
A user can click on the insect category and receive all 21 insect pests.
“If the users don’t want to search by type then they can choose differentials based on leaf condition that has 12 options or leaf color that has 10 options,” Whipker said. “They can also search by leaf location, which has six options. Fruit conditions have eight options, including size, texture and color. There are also attributes for root and crown problems.”

The strawberry diagnostic tool being developed at North Carolina State University covers 88 different attributes, including nutritional disorders such as boron toxicity (top) and iron deficiency (bottom).
Filters narrow problem identification

Whipker said the key allows users to narrow down the problem identification by using a series of filters.

“If a grower has interveinal chlorosis, the key can filter the problem down to 12 options,” he said. “The grower can add another filter for mature leaves, which narrows the choices down to four options. The key then filters for a combination of interveinal chlorosis and mature leaves.
There are other characteristics that are listed and the grower can read down that list and sort the problem cause from there. There is one thumbnail photo of each problem that the user can choose from.”
There are different headers for each of the four categories. For diseases there are headers for causal agents including the scientific names. The headers for nutritional disorders include Problem (i.e., iron deficiency); Symptoms (with photographs and a listing of similar problems like mimics); Additional Information; Diagnostic Tips; Corrective Measures and Management.
Whipker said once a grower chooses what he thinks is causing the disorder, he can click on the problem and is taken to a fact sheet.
“There are 88 attributes and there is a fact sheet on each one,” he said. “Most of the fact sheets are two pages long. Some of the disease fact sheets are four to six pages. There are also some hyperlinks for other online resource publications that are available.”
Additional crop information

Whipker said the key template that was used for the strawberry diagnostic tool would have application to other crops.

“Diagnostics are my driving force,” he said. “I have invested $20,000 in a system that can induce nutrient disorders. I’d like towork on the nutrient disorders of greens and herbs. Currently there is no diagnostic key available for herbs.”
Whipker has also produced a nutrient disorder guide for tomatoes, “Tomatoes: Troubleshooting Guide to Nutritional Disorders”.
N.C.  State University horticulture professor Brian Whipker has released a book on tomato nutrient disorders that were greenhouse-induced.

“We produced an iPad-based book for the tomato disorders,” he said. “It is also available as a print-on-demand book at Lulu.com.

“The tomato disorder publication is more applicable to greenhouse tomatoes than field-grown. All of the tomato nutrient disorders were greenhouse-induced. A field-based system is more forgiving. With a hydroponic or water-production system there is no residual. If a grower forgets to put in boron, the plants are going to show the deficiency symptoms.”

For more: Brian Whipker, North Carolina State
University, Department of Horticultural Science; brian_whipker@ncsu.edu.

A team effort

North Carolina State University team members on the “Strawberry Diagnostics: a Problem Solving Tool” project include:
Hannah Burrack, Department of Entomology
Frank Louws and Barbara Shew, Department of Plant Pathology
Rocco Schiavone, Jeremy Pattison and Brian Whipker, Department of Horticultural Science
Rob Ladd (developer) and Rhonda Conlon, Extension Information Technology

David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.

Update on trialing supplemental lights in Hawaii

By David Kuack

On Dec. 14, 2014, a Hort Americas blog update was posted about University of Hawaii graduate student Robert Saito, who is
comparing the growth of pak choi (Chinese cabbage) under T5 fluorescent lamps
and Philips GreenPower LED Production Module Deep Red/Blue 120 fixtures. Saito
has conducted seven trials. The first four trials were preliminary to determine
the best growing medium and which plants should be used to measure light effect
differences. Initially Saito was planning to grow mizuna, but he ran into
issues with micronutrient deficiencies and switched to pak choi instead. Both
of these leafy greens are in the Brassica family.

University of Hawaii graduate student Robert Saito is studying
the differences in growth of pak choi under fluorescent (top)
and LED lights (bottom).
Photos courtesy of Robert Saito


Preliminary results
Saito has measured fresh weight, height and chlorophyll
content of the plants grown under the two light sources.
“I also took SPAD readings to measure the relative chlorophyll
and there were differences among the treatments,” Saito said. “I am now going
to run the data statistically to see if there was a significant difference.”
Plant samples are also being analyzed for nutrient
content to see what kind of nutritional value they can offer to consumers.
“I am doing a tissue analysis to measure some of the
secondary metabolites,” he said. “I am looking at total phenolics, carotenoids
and glucosinolates. A mineral nutrient analyses will measure such things as
total nitrogen, phosphorus and potassium. Once the mineral and tissue analyses
are done then I hope to publish the results.”
For more:
Robert Saito, University of Hawaii, College of Tropical Agriculture and Human
Resources, Manoa, Hawaii; rjnsaiot@hawaii.edu.
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com. 
Visit our corporate website at https://hortamericas.com

It’s time to become water-smart

As more growers look to install closed loop irrigation
systems, there is a need for treatment systems specifically tailored to handle
horticulture issues related to biofilm and disease control.

By David Kuack

 

The intense drought in California and continuing drought
in Texas along with their impact on the rising cost of food are making
government officials and the public painfully aware of the importance of having
and maintaining a reliable water supply. USA Today reports that California
produces nearly one-fifth of the United States’ entire agricultural output.
Should the state’s water woes continue the newspaper said farmers and
distributors may soon have to start looking for alternative locations to grow
or buy their crops.

Continue reading It’s time to become water-smart

Hort Americas to participate in and sponsor Tour de Fresh 2014

Chris Higgins, general manager at Hort Americas, will be riding in the Tour de Fresh 2014 sponsored by United Fresh Produce Association. The four-day cycling ride starts
on Oct. 13 in Carmel, Calif., and finishes in Anaheim on Oct. 16, the day
before the opening of the Produce Marketing Association’s Fresh Summit
Convention & Expo.

This not-for-profit event will align fresh produce
growers, shippers, packers and vendors, as well as family and friends of the
industry, and will benefit the United Fresh Produce Association’s Let’s Move Salad Bars to Midwest Schools campaign.
Higgins will be riding to collect money for the Mattawan
Consolidated School district in Mattawan, Mich. The school district is seeking
funds to install four salad bars in its schools.
Higgins attended Mattawan middle school and high school
while growing up in Michigan. Hort Americas is also a bronze sponsor of the cycling
event.

Visit our corporate website at https://hortamericas.com

Daily light integral: a better way to measure greenhouse light

Measuring daily light integral (DLI) provides a more
accurate reading of the amount of photosynthetic light being received by
plants.

By David Kuack

Do you measure the light in your greenhouse to ensure
your plants are receiving an adequate amount of light? If you are using a
footcandle meter to measure the light intensity you are not getting a true
measurement of the amount of light received by the plants. Measuring the light
in footcandles or micromoles per square meter per second (µmol/m2/s) is
a measurement of instantaneous light, that is, the amount of light at the time
the measurement is made. An instantaneous measurement made under sunny or cloudy
conditions may not provide an accurate evaluation of the total amount of light
perceived by the plants over the course of a day.

“When you think about light over the course of a day,
light is extremely dynamic,” said assistant horticulture professor Chris Currey
at Iowa State University. “From sunrise to sundown, there are variations in
light. If growers take a single light measurement early in the day, they may be
underestimating the amount of light. Alternatively, if the light measurement is
made later in the day, growers may be overestimating the light level.
Instantaneous light levels change over the course of a day.”
Visible light vs.
photosynthetic light

Currey said another issue with measuring light with a
footcandle meter is that it measures the light that is visible to the human
eye.

“The sun produces a broad spectrum of light,” he said.
“Photosynthetic light, which is the light plants can use for photosynthesis and
is defined as photosynthetically active radiation (PAR), is the light that
occurs between 400 and 700 nanometers. So if a footcandle meter measures light
that is visible to the human eye, this includes wavelengths outside of PAR.
Consequently, footcandle measurements tend to overestimate the amount of light
for plant growth.”
More accurate
measurement

Currey said it is the total amount of photosynthetic
light that is going to impact how a greenhouse crop is going to grow.

“Daily light integral (DLI) is the sum of photosynthetic
light over the course of a day,” he said. “In production situations where there
is a static light source it is relatively easy to determine the DLI. Examples
of a grower producing a crop under a static source of light include growing
plants under high pressure sodium lamps in a warehouse or tissue culture plantlets
grown under LED lights in a laboratory. In these situations the light levels
are not going to change throughout the day.
“In most greenhouse environments light levels change
throughout the day. So to take one instantaneous measurement to indicate the light
level isn’t the best way to describe the total amount of PAR light available.
It’s better to look at the total amount, which is the DLI.”
Currey said a grower could estimate the DLI by using
hourly measurements.
“A grower could go out into the greenhouse every hour and
measure the light intensity,” he said. The grower would then use these
measurements in some calculations that would give the DLI. Realistically, very
few growers are going to determine DLI this way.”
There are a number of instruments available for measuring
DLI. Currey said one of the best ways to determine DLI is to use a quantum
sensor that measures PAR. The unit of measurement for DLI is moles per square
meter per day (mol/m2/day).
“In many cases the quantum sensor is connected to a data
logger that records the light measurements,” he said. “The quantum sensor can
be attached to a data logger that can record frequent instantaneous light
measurements which can then be integrated into a cumulative total for the day.
The quantum sensor can also be hooked up to a greenhouse environmental control
computer, such as an Argus or Priva, which can calculate the DLI.”
Expanding use of
DLI

Researchers at Clemson University used light measurements
collected by the National Oceanic Atmospheric Administration to developed
monthly DLI maps for the United States.



Monthly daily light integral maps for the United States
were developed using light measurements collected by
the National Oceanic Atmospheric Administration. The
 maps are based on historical averages.
Photo courtesy of Michigan State University
Currey said the maps are based on historical averages.
“The DLI maps give you a good average,” he said.
“Poinsettia growers will tell you each growing season is different. Sometimes
they will have bright, sunny Novembers and other years, it’s dark and cloudy.
These maps provide a good indication of light levels, but there are going to be
variations between years. That’s why it is important for growers to measure DLI
so they know what is happening in their greenhouses and be able to react,
including using supplemental lighting to increase DLI.”
Currey said that research has been done to quantify the
DLI necessary for specific crops.
“The optimum DLI is going to vary for different crops,”
he said. “For African violets, a DLI of 6 mol/m2/day is enough to
produce a good crop. For poinsettias, 10-12 mol/m2/day are needed to
grow an acceptable quality crop. For cut roses, the DLI needs to be above 20
mol/m2/day to produce a good crop.”
Growers are using daily light integral with their environmental
controls and supplemental lighting to provide their plants
with optimum photosynthetically active radiation levels.

Currey said some growers are using DLI, their
environmental controls and supplemental lighting to provide their plants with optimum
PAR levels.

“It is kind of like predictive lighting,” he said.
“Growers have their lights turn on when the light intensity is below a certain
level and turn off when the light goes above a certain level. This way a grower
is not adding light during the brightest time of the day when the light level
is at or above the light saturation point for photosynthesis. Growers can use
lighting set points so that if they are not achieving the target DLI for a
crop, they can have the lights turn on sooner or turn off later to ensure
plants receive enough PAR. As a crop goes later into the spring, a grower is
likely going to lower that trigger light intensity because there is going to be
more natural sunlight so less supplement light is needed.”

For more: Christopher
Currey, Iowa State University, Department of Horticulture; (515) 294-1917; ccurrey@iastate.edu.

David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.

Visit our corporate website at https://hortamericas.com

Nepris

“Education is not the filling of a pail, but the lighting of a fire.” – William
Butler Yeats

What led you to where you are today?  Chances are someone or something, somewhere,
influenced you to make a series of life choices that have led you to where you
are today.  For some, it is a high school
class that inspires them to pursue their career.  For me it was an after school job during high
school.  One persons’ desire to grow
tomatoes during the winter in North Central Kansas ultimately led me to pursue
a PhD in plant science. 

At some point in your professional career you’ll most
likely be asked to speak in front of an audience.  Speaking engagements for industry
professionals are generally reserved for industry trade shows and
conferences.  Sometimes, we’re invited to
speak to a group of college students during what is formally known as “seminar”.  Informally, it is known as nap-time! 

What if you could make a potentially long-lasting
impression to a younger demographic?  One
where the majority of the audience chooses a high tech career during their
middle or high school years?  And you
could do this without leaving your office. 
Enter, Nepris…

What is Nepris?  Technically, Nepris is “an online platform
that makes it easier for teachers to connect with industry experts to bring the
real world to the classroom.”  According
to their website “57% of boys and 68% of girls who chose a high tech career say
they were inspired by one person, or one event, or one class during the middle
or high school years (STEM Perceptions study by Microsoft).  What is STEM? STEM is an acronym for Science,
Technology, Engineering, and Mathematics. 
You can learn more about STEM, here.

Basically, the Nepris platform allows educators to post a
curriculum topic to the Nepris platform and then assists by finding an industry
expert to show and tell how that topic is applied in practice.  Industry experts must also create an
account.  The process is simple and there
are plenty of tools to help you build your presentation framework.  I should also stress that the team at Nepris
is VERY helpful.

In January, Hort Americas (yours truly) was given the
opportunity to engage high school students of an advanced biotechnology class in
TX.  The students are working on individual
class projects and many of them chose the topic of hydroponics.  Their teacher knew little about the subject
of hydroponics and elected to utilize Nepris to help the students learn from an
industry expert. The presentation title (selected by the teacher) was “Growing
Crops with Hydroponics”.  The process was
very simple.  I created my online
account, found the topic, read the description and signed up as the
speaker.  There were a few dates and
times to choose from, so I selected the one that best fit my busy
schedule.  The Nepris team reached out to
me immediately and we set aside 30 minutes to go over the process and content
of the presentation and that was it until the day of the presentation.  When the day of the presentation arrived, I
logged into my account 10 minutes early, made introductions and gave the
presentation.  This particular class
repeats, so students can remain enrolled in the class over multiple semesters.
This means that some of the experiments may continue over a longer period of
time.  I offered my knowledge and
services to the class, so there is the potential of creating a long-lasting
impact on some of the students.  Who
knows, perhaps one of them will become one of our industry’s next leaders.  You never know. 

So what’s the point? 
OUTREACH!  Participating in this
platform allows us to tell our story to more people.  It also allows us to explain the breadth of
our industry.  Think about it, greenhouse
agriculture has it all. Not only does it include STEM, but it also includes
business, sales, marketing, architecture, nutrition, culinary arts and so
on.  If you’re interested please check
out the Nepris website and
create an account.  Then find a
presentation, tell students how cool your job is and expose them to the “real
world”. 

Article written by Hort America’s Technical manager, Dr. Johann Buck. 

Visit our corporate website at https://hortamericas.com

Hort Americas sponsors Indoor Agriculture Conference

The 2nd Annual Indoor Agriculture Conference will take
place May 14-15, 2014, at the Springs Preserve in Las Vegas. The conference
will bring together farmers, entrepreneurs, suppliers, technology geeks,
investors, researchers and policy makers to discuss the status and future of
hydroponic, aeroponic and aquaponic farming.

Sponsored by Hort Americas, the conference highlights the
accelerating greenhouse, container and vertical farming trends that are gaining
ground in urban centers and inclement environment locations worldwide.
Indoor agriculture is changing the farming paradigm. Increased
technology and adaptation of hydroponics and aeroponics are enabling indoor
agriculture to conserve land, water, energy and distribution costs. The reliability of indoor agriculture becomes even more
important when compared with the expense and uncertainty of outdoor
agriculture, which can be disrupted by weather or supply chain problems. Growing indoors also promises higher levels of food safety, as fresher produce
grown using few to no pesticides is transported shorter distances allowing for the
reduction in contamination during production and distribution.
Keynote presentations will focus on the state of the
hydroponics industry. Panel discussions will address the future of indoor
agriculture, types and sizes of operations, technology, sourcing and
distribution, regulations/policy and funding. On the second day, case studies will
examine in-depth, real-world examples of the logistics of starting, sustaining
and growing indoor agriculture operations.

Visit our corporate website at https://hortamericas.com

The changing face of horticulture

Michael Geary, president and CEO of the new trade
association AmericanHort, talks about how the horticulture industry is evolving
and what the association is doing to ensure plants remain relevant to consumers.

By David Kuack
The start of 2014 brought a new trade association,
AmericanHort, to the horticulture industry. Although the name is new, the
association represents 220 years of service to the industry through the
combined history of the two organizations that created it. AmericanHort was
formed by the consolidation of the American Nursery & Landscape Association
and OFA – The Association of Horticulture Professionals. The more than two-year
effort was approved by the two associations’ members in September 2013.

 The mission of AmericanHort is to unite, promote and
advance the horticulture industry through advocacy, collaboration,
connectivity, education, market development and research. Its vision is to be a
leading and unifying organization for the industry in order to cultivate
successful businesses, and for the industry to enhance lives through the
benefits of plants.

The new association will represent all segments of the
plant industry. This includes breeders, greenhouse and nursery growers, garden
center retailers, distributors, interior and exterior landscapers, florists,
students, educators, researchers, manufacturers and all of those who are part
of the industry supply chain.
Michael Geary, former CEO of OFA and executive vice
president of ANLA, who is now president and CEO of AmericanHort, talked with
Hort Americas about the changing horticulture industry and how the new
association is working to ensure the industry remains vital and its members
continue to be successful.

Michael Geary, president and CEO of AmericanHort
Photo courtesy of AmericanHort

How has your definition
of the horticulture industry changed?

The definition of horticulture has been an evolution for
me. While I didn’t work directly in the industry prior to taking the job with
OFA, my father used to work for the U.S. Forest Service. He was involved with
forest management, breeding and plant pathology at a research station in Fort
Myers, Fla. So I was exposed to the research side of horticulture. As a young
child I would go to the research station with my father and into the
greenhouses and into the field with him and measure plants and take data. That
was my only exposure.

When I started to work in the industry I didn’t fully
understand what is encompassed by the industry. As I talked to other people my
interpretation of horticulture came to include the production, distribution and
selling of plants.
Early on I used to wonder whether people who operate
garden centers think of themselves as being part of the horticulture industry.
They are. They are very integral, sometimes in the production of plants, but certainly
in the distribution, selling, promoting and services related to plant material.
The word “horticulture” has a very scientific connotation
to it, but it’s more than that. It goes beyond production and research. It
involves everything with how we experience the plant world. It’s really
everything that is involved with plants.
How do you think
the horticulture industry is evolving in regards to the types of plants that
are being grown and sold?

Edibles are definitely a part of the horticulture industry.
Not necessarily big agriculture, which would include crops such as corn,
soybeans and wheat. We don’t really think about those crops in the context of
what AmericanHort does as an organization as being a part of horticulture.

Edible crops that are grown in greenhouses, plants grown
by consumers in their backyards or on their porches and patios, those would be
included as a part of horticulture.
AmericanHort has been engaged for a while talking about
edibles to greenhouse growers. There has been a push for vegetables and fruits
that consumers can grow and I expect that will continue to increase. We are
also looking at how growers can produce product for a larger market similar to
what big ag is doing selling to wholesalers or directly to grocery stores.
Growers are looking at alternative crops. If a grower’s
greenhouse is empty in January, why not fill it with something like tomatoes or
green peppers? How do they do that? What does it take to do that sort of thing?
What are the economics of growing an alternative crop? Those are the types of
things that we are discussing within the association committees and with our
staff and leadership. It’s not something new, we’re just looking at what more
can we do to support the membership.
There are so many opportunities for alternative crops.
The association can support these crops through educational sessions at
conferences, but also through research that is necessary and all of the
marketing and other business components that go along with these alternative
crops.
OFA and ANLA were
considered to be “grower” organizations? Do you think that perception will
start to change with AmericanHort?

AmericanHort, although it does have a focus on production
techniques as part of its educational programs, we are not only about
production. You can be an amazing plant grower, but you have to know how to run
a business also. I hope that people will look to AmericanHort not just to get
information on diseases and plant production, but to also look to the
association for support in regards to business management and business skills,
which are also necessary in order to provide a great product to the
marketplace.

With the consolidation of the two associations,
AmericanHort is now the largest organization of garden retailers. You can
expect to see and hear more from us about growing the retail end of the market
chain. For years we have been offering a trade show and a variety of
educational opportunities for retailers and there’s more to come. AmericanHort
is for every business sector in the industry.
Also, AmericanHort’s support for the industry includes
government relations activities in Washington, D.C. Those issues are extensive
and impact all sectors of horticulture.
What is
AmericanHort doing to ensure that the horticulture industry and its products
and services remain relevant to consumers?

There is whole generation of people who have not really
experienced our products and services. AmericanHort received a USDA Specialty Crop Block Grant
to study the interest of young people in plants and gardening.

The association will be working with Michigan State University
horticulture professor Bridget Behe and Meister Media on this project. We are
trying to understand now what Generation Y and Millennials will be interested
in the years to come. When they get to the age when they are buying their first
major home or having children, we don’t know what they are going to be
interested in then. We don’t think that we can make an assumption that they are
only going to be interested in technology and they’re never going to be
interested in the nature side of life.
We are conducting focus groups and other research
including one-on-one interviews with younger people to learn about their
shopping habits and interests. What are they interested in at that age level
and how they want to be engaged.
Young people are interested in nature. This generation
cares about the environment. But what are they going to buy and use, we really
don’t know yet. We can’t make assumptions. We are just starting now to research
and understand and prepare for that when that generation is prepared to buy
more than just music and iPhones.
We are not only trying to help by doing this research,
but we are also trying to get individual businesses to be more successful.
We’re trying to help owners to better manage their people, dollars and their
products.

For more:
AmericanHort, (614) 487-1117; hello@AmericanHort.org; http://americanhort.org.

David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.com.

Visit our corporate website at https://hortamericas.com

Monitoring Irrigation Water Quality

Testing your irrigation water quality is important and
should be done regularly.  Frequency of water
samples is dependent on several factors. Growers should test their irrigation
water at least twice a year if producing crops year round.  I know one grower that tests their water
weekly!  At Hort Americas we are becoming
inundated with fertilizer requests and nutritional recommendations.  The first question we’ll ask is “Do you have
results from a recent irrigation water quality test?” If the answer is yes,
great, please forward a copy of the results to us.  If the answer is no, please have your irrigation
water quality tested.  Next question,
“How do you sample your irrigation water?” Collecting water samples correctly
is important to ensure the results are accurate. 

If you are not testing your irrigation water, why
not!?!  That is one of the first things
you should do before a single seed is sown. Why? Well, if you don’t measure it,
you can’t manage it.  On one hand, you
could be undervaluing your irrigation water by adding unnecessary soluble nutrients.
On the other hand, your irrigation water may be unsuitable for crop production
and/or require additional treatment before use. What do I mean?  The irrigation water chemistry made need to
be treated to remove or correct nutritional issues. Or, your irrigation water
may have unwanted sediments that must first be filtered.  Entire books are written on irrigation, so we
cannot cover everything in one edition of an e-newsletter.  For now, let’s first focus on collecting the irrigation
water sample.  As you recall, last month
I shared some videos on growing winter salad greens created by Dr. Brian Krug
from the University of New Hampshire.  Once
again, Dr. Krug has composed both a valuable how-to article and a video to help
you correctly collect an irrigation water sample. 
Check out this article from October, 2012 or, watch another
FloriCAST video by Dr. Brian Krug.
Irrigation Water
Sampling Summary:
·        
Have the right tools e.g. hose or spigot,
bucket, collection bottle, paper towels, submission form, envelope etc.
·        
Flush the water line/hose for at least 3 to 5
minutes
·        
Fill collection bucket
·        
Use a clean collection bottle/container (at
least 8 ounces)
·        
Submerge and fill the collection bottle and cap
under water (no head space)
·        
Complete a submission form (if provided by
testing lab)
·        
Dry and label the collection bottle accordingly
·        
Deliver the envelope to the testing lab
·        
Wait for results
·        
Send Hort Americas a copy of your results J
For more information on irrigation water quality you may
want to read the following extension publications.  Many state extension agencies have produced
similar articles. These are simply two examples of such articles.  Check with your local extension specialist as
they may have more information relevant to your geographic location.

You may also want to
visit the Water Education Alliance for Horticulture. The Water Education Alliance for Horticulture is a team
of researchers and industry experts led by the University of Florida.  Their mission is to “help growers conserve
irrigation water and manage water quality issues.”

Written by Dr. Johann Buck, Technical Service Manger at Hort Americas 
Posted by Maria Luitjohan  

Visit our corporate website at https://hortamericas.com

Trialing supplemental lights in Hawaii

Although most people wouldn’t think that supplemental
lights would be needed to grow plants on the Hawaiian Islands, they may be able
to provide growers with a consistent, quality light source. University of
Hawaii graduate student Robert Saito is comparing the growth of pak choi
(Chinese cabbage) under T5 fluorescent lamps and Philips GreenPower LED
Production Module Deep Red/Blue 120 fixtures.

University of Hawaii research is comparing the growth of pak
choi (Chinese cabbage) under fluorescent lamps and LED lights.

“Some parts of Hawaii don’t have high light levels,”
Saito said. “There is also Kilauea volcano on the Big Island that’s been increasingly active since 2008. It
is spewing all kinds of emissions into the air, which can impact the quality of
plants grown outdoors. Field growers may be able to benefit from growing their
plants using supplemental lights in greenhouses or other indoor growing facilities.”

Saito is conducting three production trials growing pak
choi in an OMRI-certified peat-based growing medium.

Most people probably think Hawaii receives plenty of sunlight
for outdoor crop production. University of Hawaii graduate
student Robert Saito is trying to determine if indoor vegetable
growers could benefit from using supplemental lights.      

“The entire experiment is being done indoors,” Saito
said. “The plants are on a 14-hour photoperiod. The focus of my experiments is
on the benefits of using supplemental lighting. I have been looking at what are
the differences and similarities of growing pak choi under fluorescent lamps
and LEDs.”
For more:
Robert Saito, University of Hawaii, College of Tropical Agriculture and Human
Resources, Manoa, Hawaii; rjnsaito@hawaii.edu.

Visit our corporate website at https://hortamericas.com

Specialty Greens produces better crops with grow lights

Specialty Greens in Lafayette, Calif., is hydroponically
producing gourmet lettuces, herbs, chard, spinach, kale and microgreens. Owner Patty
Phaneuf has been working with Hort Americas to study the effects supplemental
production lighting can have on her lettuce and herb crops. She is using Philips
Green Power LED Production Modules Deep Red/Blue 120cm and T-5 fluorescent
lamps. T-5s produce light that is high in the blue light spectrum (440
nanometers).

Phaneuf said the lettuce grown under the LEDs and
fluorescent lights had accelerated growth and intensified leaf color. Using the
lights enabled her to produce the lettuce within a 30-day crop cycle from seed
to harvest.

Phaneuf was so pleased with the lettuce production
results that she is planning to expand the lighting trials. She is working with
Hort Americas to increase the amount of blue light given off by the LED
Production Modules so that she can eliminate having to use the fluorescent
lights.
 

 

For more:
Specialty Greens, www.specialtygreens.com.

Experiment information provided by Patty Phaneuf at
Specialty Greens. Posted by Maria Luitjohan at Hort Americas,
www.hortamericas.com.

Visit our corporate website at https://hortamericas.com

Creating the ”perfect” vegetable plants through grafting

Controlled-environment growers have long known the
benefits of grafted plants. Field growers are quickly learning them too.

By David Kuack

Plant grafting of plants has been done for thousands of
years. Preparing and using grafted vegetable plants is common in Asia, Europe
and other regions and is gaining use in North American production systems. North
American greenhouse and high tunnel growers were the first to use grafting most
routinely, but field vegetable growers are showing increased interest in the
benefits grafting has to offer.

Grafting joins the root system of one variety to the
shoot of another variety to create one “hybrid” plant. The plant used for its
roots is called the rootstock. The plant used for its stems and leaves to
produce marketable fruit is the scion.

Matt Kleinhenz, professor and extension vegetable
specialist at Ohio State University-OARDC in Wooster, Ohio, said the number of
vegetable crops that are being grafted is steadily climbing.

“Currently the core crops include tomato, watermelon,
cantaloupe, pepper, cucumber and eggplant,” Kleinhenz said. “These crops are
grafted for various reasons, including their financial value and because their
production can be limited by issues that grafting can address.”

 
Advantages of
grafted plants
Kleinhenz said there are a number of potential benefits
provided by grafting. These benefits apply to both the person who creates the
grafted plants and the one using them.

“The broadest description of the benefits of grafting may
be that it makes better use of genetics in production,” he said. “Single commercial
fruiting varieties are often hybrids. When developing them, the breeder attempts
to incorporate most or all of the traits that matter into each one. That
process is resource demanding. It takes time and money. It’s technically
challenging and it always involves compromise. Each and every variety is
imperfect in some way. A variety may be better than its predecessors, but it is
still imperfect in some way.”

Kleinhenz said there a number of ways in which hybrid varieties
can be imperfect. They can be less resistant to soil-borne diseases or
deleterious nematodes. They can use water or nutrients inefficiently. They can
be susceptible to various forms of abiotic (nonliving) stresses including cold,
heat or salinity.

“Instead of incorporating all of the desirable traits
into one variety, grafting creates an instant combination of two varieties,” he
said. “The attributes of the two varieties are specifically chosen, but there
is no attempt to blend them into one particular genotype, as in traditional
hybrid development. Instead, grafting provides the best of both varieties by
splicing them together. Through that splicing a new “physical” hybrid is
created for use in that production season only.”
Grafting provides the best of two plant varieties by splicing
them together.
Photos courtesy of Matt Kleinhenz, Ohio State University-OARDC

Kleinhenz said traditional development of a standard
hybrid must overcome barriers to the crossing of the parents, the movement of
traits from one plant to another and the possibility that bad traits tag along.

“In grafting, two varieties must be compatible to be
grafted,” he said. “Grafting allows for the bypassing of difficult and
time-consuming steps that are required to create a superior variety that is
good from top to bottom. For this reason, grafting may increase both the range
of traits available to growers and the speed into which they come onto the
farm.”

Kleinhenz said in those systems that rely heavily on
grafting, scion varieties are bred to produce high quality fruit and rootstock
varieties are bred to power the scion. The scion does not need to resist or
tolerate soil-borne stresses and the rootstock does not have to produce
marketable fruit.

He said grafting combines two excellent varieties in a
matter of seconds. However, an average of two to three weeks may be required to
prepare the seedlings to be grafted and to allow newly grafted plants to heal
before transplanting them.
An average of two to three weeks may be required for newly
grafted plants to heal before they are ready to transplant.
Grafting potential

“Grafted plants are primarily used to limit losses due to
soil-borne diseases and deleterious nematodes,” Kleinhenz said. “Grafted plants
have shown the ability to limit losses caused by organisms that attack the root
system or the lowest shoots just above the soil line. Grafted plants are not
widely used to combat foliar or fruit diseases such as late blight of tomato
that essentially attack the shoot well above the soil line. Foliar disease
management is still primarily the responsibility of the scion.”

Kleinhenz said grafted plants have also performed well under
less than ideal growing conditions.

“Tests completed where soil salinity was high, where soil
moisture was excessive, and when soil temperatures were low have demonstrated
the high potential of grafted plants,” he said. “Grafted plants have also
out-yielded ungrafted ones when conditions were good and they have been able to
use water and fertilizer inputs more efficiently. Researchers and farmers are
testing the performance of grafted plants worldwide under many conditions to
discover where and when using them makes the most sense.”
The performance of grafted plants is being tested under many
conditions worldwide to discover where and when using them
makes the most sense.

Kleinhenz said the preparation and use of grafted plants
is market-driven.

“If users see the benefits, suppliers will offer them,”
he said. “Potential suppliers will be reluctant to prepare large quantities of
grafted plants until they are confident people will buy them.

“I recommend that potential users try them. Local
suppliers and extension personnel can assist in getting started. Growers can
also prepare their own grafted plants with just a little practice. Hands-on and
free web-based training guides are widely available.”

Playing catch up

The use of grafted vegetable plants in soil-based
production systems is much more common outside North America.

“The current cost of grafted plants, unfamiliarity with
the full benefits of using them, not being sure how to use them and their
occasionally inconsistent performance may explain the situation,” Kleinhenz said.
“Early adopters are already fairly convinced. Others are taking a more
wait-and-see approach. Adoption curves for new practices and technologies tend
to be similar. The benefits have to be clear, consistent and compelling to a
core group of growers. Then, word spreads.”

Kleinhenz said even though grafting is not new, until
recently there have been limited resources available in North America for
widespread and intense evaluation.

“The demand for alternative disease management strategies
and vigorous and resource-efficient crops is high,” he said. “New rootstock
varieties are available. More and more people have at least heard of grafting,
grafted plants themselves and/or grown grafted plants. And, the pool of
research-based information to aid growers is expanding.”

For more: Matt
Kleinhenz, Ohio State University-OARDC, Vegetable Production Systems
Laboratory; kleinhenz.1@osu.edu; http://hcs.osu.edu/vpslab.

David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.com.
 

Learning how to graft
The “Grafting Guide,”
available from Ohio State University-OARDC, offers a detailed, easy-to-follow
look at the entire process of grafting. It would be of interest to both
inexperienced and experienced grafters.
This comprehensive pictorial guide discusses the splice-and-cleft
graft method for tomato and pepper. It provides information on selecting
rootstocks and how to evaluate the suitability of grafted plants for use in
field and high tunnel production.
Included in the guide are a tomato rootstock table, seeding
calculator, stem diameter chart, seed treatment fact sheet, healing chamber
design and other reference materials. New additions to the guide will be
prepared as experience and research-based information become available.

Grafting symposium scheduled for Nov. 6

The 2nd annual Vegetable Grafting Symposium will be held Nov. 6, 2013, in San Diego, Calif. The event is being convened by
a USDA Specialty Crop Research Initiative-Supported University-USDA-Industry
Team hosted by the Annual International Research Conference on Methyl Bromide
Alternatives and Emissions Reductions.

The symposium’s objectives include:

1. Summarizing the current status and expected future of
grafting as a technology for enhancing U.S. vegetable production systems
related to profit, resource efficiency and sustainability.
2. Increase the understanding of challenges and
opportunities associated with preparing and using grafted vegetable plants.
3. Strengthen and diversify partnerships required to
widen the application of vegetable grafting as cornerstone technology.
4. Describe the USDA-Industry Team’s goals and approaches.

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Updated: LED Grow Lights used in Leafy Green Trials

Specialty Greens
experiment is going well. In the first eight-ten days, Specialty Greens saw
little difference between the LED lights and the T-5 lights, but as we
approached the two week mark Specialty Greens began to see significant differences,
as seen in the photos. There does not seem to be an appreciable difference
between the two LED light set up and the three light set up. The main
difference I am noticing is that there is a bit less color in the leaves of
lettuce produced under the LED lights. There is however, amazing growth and in
looking at the photos of the Mizuna leaves, it’s clear that as a commercial
grower, Specialty Greens could get two, possibly three harvests out in 30 days.
Overall, everything is growing well and if were it not for this experiment, Specialty Greens
would have pulled some of the crops a week ago (e.g., kale, mizuna, some
lettuces).
Chard under Two LEDs
Chard under Three LEDs
 
 
Specialty Greens also decided to compare Hort
Americas LEDs to T-5 lights. In these photos Specialty Greens tried to show the
visible difference between the plants grown under the LED lights (in each photo
they are the larger plants) vs growing under T-5 lights and the incredible
difference between the small (background) and large (foreground) Mizuna leaves
 
Mizuna grown under LEDs on Left, T-5’s on right
 
Mizuna grown under LEDs on Left, T-5’s on right

Also showing the difference in Chard growing under LED
lights (left) vs T-5 lights. (right)

Experiment information provided by Patty Phaneuf from Specialty Greens, and Posted by Maria Luitjohan from Hort Americas.
Visit our corporate website at https://hortamericas.com

LED Grow Lights used in Leafy Green Trials

Philips GreenPower Production Module LED Experiment with
Specialty Greens in Lafayette, CA

Lights: Philips GreenPower Production Modules Deep
Red/Blue 120cm

Objectives: 1.) Can a variety of greens (gourmet
lettuces, high nutrient greens and herbs) be grown under production LED lights
well enough and quickly enough to be commercially viable. The target is a 30
day cycle from seed to harvest.

2.) Would two lights per hydroponic unit (ez clone
cloner) achieve this goal or are three necessary?

Seeded: 9/15/13

Experiment under lights began: 9/26/13
Initial recommendation to hang lights 16-18” above plants produced
leggy and weak seedlings.  Lights
remounted above plants 7-8” Philips GreenPower Production Modules are being run
14 hours/day.  Ambient room temperature
ranges from 70 degrees during the night to 85 degrees during the day. The
nutrient used is DynaGrow at a dilution of 1/2 teaspoon per gallon so about 5-6
teaspoons per cloner. ProTect, an auxiliary nutrient, was used at the same
dilution. An ArtDne recycling timer is being used 24 hours per day at a rate of
1 minute on for every 5 minutes off. There will be one nutrient change during
the experiment after approximately two weeks to refresh the set up and new
nutrient will be applied at the dilution described above.
Specialty Greens is providing growers interested in hydroponics all the they need to grow hydroponically in a 2 ft sq. space!
To
find out more about Specialty Greens Check them out here or like them on Facebook
Here are some photos taken of the Experiment on 9/26/13

Experiment information provided by Patty Phaneuf from Specialty Greens, and Posted by Maria Luitjohan from Hort Americas.
Visit our corporate website at https://hortamericas.com

Using LEDs to manipulate plant growth, characteristics

With the ability to deliver specific light wavelengths
with LED lights, growers, retailers and consumers could eventually manipulate
the scent, color, flavor, postharvest life and other characteristics of
ornamental and edible crops.

By David Kuack

Both ornamental and edible plant growers are using
supplemental lighting. Some use light to control photoperiod. Others use
supplemental light to hasten plant development by increasing the rate of
photosynthesis.

What if you could use light to increase the flavor,
aroma, color intensity, insect and disease resistance and postharvest life of
edible crops? What if you could use light to increase the fragrance, color
intensity, insect and disease resistance, flower timing and postharvest life of
ornamental flowering plants? Sound like science fiction? Read on.

Talking to plants

Kevin Folta, interim chair and associate professor of the
Horticultural Sciences Department at the University of Florida, said the
fundamental idea of using light to manipulate plants is an old one.

“We’ve known for a long time that light can affect
photosynthesis, but we are now starting to understand how light can regulate specific
plant responses,” Folta said. “It’s no big surprise that light could manipulate
something like flavors or any other aspect of plant metabolism.”

Working with other scientists at the university’s
Institute for Plant Innovation, Folta said
initial research indicates red, far red and blue light are the three major
wavelengths that affect volatile accumulation in plants. The researchers have
studied the impact of light wavelengths on strawberries, blueberries, tomatoes
and petunias.

“Volatiles are the chemicals that contribute to the aroma
and flavor that are released,” Folta said. “Volatiles are the chemicals that
are emitted that allow you to smell and taste a piece of fruit. These are the
compounds that are really important in providing flavor to fruit and
vegetables.”

University of Florida associate professor Kevin Folta and other
scientists at the university’s Institute for Plant Innovation are
studying the impact specific light wavelengths can have on
plant characteristics.
Photo by Tyler Jones, UF/IFAS Photography  

 Folta said similar changes could be made to flowering
plants by manipulating the light wavelengths that the plants are exposed to.

“For ornamentals we could affect aromas, colors and
flower timing by changing the light environment—the specific wavelengths,” he
said. “It would be possible to synchronize an entire greenhouse of plants to
flower at the same time just by flipping a switch. By understanding the light
spectrum and how a plant sees it, it could allow us to manipulate how a plant
grows.

“It’s almost like we can talk to the plants. It’s a
language that is essentially a vocabulary of light wavelengths and that we can
use to influence how a plant grows.”

Focused on LEDs

Folta said all of the research being done involves the
use of LED lights.

“LEDs allow us to deliver very precise amounts of
specific wavelengths,” he said. “LEDs allow us to mix the light conditions
precisely. We can pick and choose the light we want to use.”

Folta said one of the ways different light wavelengths
could be used is to customize what the final fruit, vegetable or flower would
look, taste and smell like.

“For example, maybe we could put the plants under blue
light for a few days and then switch to far red and then red. We know that such
sequential treatments allow us to bump up the pigments, then the nutrients and
then the flavors,” he said. “This treatment could change the way we grow, ship
and sell crops, as well as how consumers store them at home.

“All plant traits are a combination of genetics and the
environment. The genetics are already in place to make a quality fruit,
vegetable or flower, so the LEDs allow us to manipulate what’s already there.
We can tweak the environment with the LEDs to alter plant characteristics.
Maybe an LED light would be placed in a box of roses. When a consumer opens the
box there would be this incredible aroma released.”

Folta said the research has tremendous potential for both
edible and ornamental crops.

“This research would probably have happened a longtime
ago, but LED lights were prohibitively expensive,” he said. “Now that the cost
of LEDs and narrow band width lighting is becoming more affordable, we realistically
see LED arrays being used in greenhouses to manipulate the way plants grow.”

Endless potential

Although the initial research has focused on changing the
taste of fruit and vegetables, Folta said the use of light could easily be
expanded to manipulate other plant characteristics.

Kevin Folta said growers may eventually be able to synchronize
an entire greenhouse of plants to flower at the same time just
by flipping a switch for LED lights.
Photo by Tyler Jones, UF/IFAS Photography

“There is an increasing body of research literature that
indicates some of the compounds emitted by plants and their fruit deter insects
or deter fungal growth,” he said. “It may be possible that we could affect
insect and disease resistance. For example, by using LED lights we could change
the metabolic profile of the plant so that poinsettias would be more resistant
to whitefly. This might be done by stopping production of plant compounds that
attract whiteflies, or producing compounds that scare them away or even better
than that may attract a predator of the whitefly.

“What we are doing is manipulating the plant metabolism
or changing it in ways that we don’t necessarily understand 100 percent yet,
but we know we can do it.”

An example of one of the results of the research he
doesn’t completely understand has occurred with strawberry plants.

“In the lab we have exposed strawberry plants to LED
lights and they don’t get spider mites,” he said. “We don’t know if there is
something that the LEDs are doing to change the development of the spider mite.
Or the light maybe doing something to the plant that causes it to produce a
chemical the spider mites don’t like so they choose to go to a different plant.
This is something that we still need to test.”

Folta said most of the previous research that involved
the same type of plant process manipulation involved inserting a gene, spraying
a chemical or other types of treatments that were labor intensive and required
other inputs.

“Now we are looking at basically flipping a switch to
turn on a low energy device,” he said. “Adding value at a low cost would be a
great thing for the horticulture industry.”

For more: Kevin
Folta, University of Florida, Horticultural Sciences Department, (352) 273-4812
office; kfolta@ufl.edu; http://www.hos.ufl.edu/faculty/kmfolta.

David Kuack is a freelance technical writer in Fort
Worth, Texas; dkuack@gmail.com.

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