Hydroponic Lettuce Production in Phenolic Foam

David Kuack and Vijay Rapaka
growing substrate materials that have been used for hydroponic crop production
include rockwool, perlite, vermiculite, expanded clay and pea gravel. Phenolic
foam is a relatively new inorganic substrate that offers many desirable
production properties.
Phenolic foam
Oasis Horticube Growing Medium is a sterile phenolic foam. Like rockwool,
Horticubes have no cation exchange capacity, no
buffering capacity and no initial fertilizer charge.
Horticubes come in a variety of sizes, including: 1-inch Thin-Cut
(276 cubes/sheet), 1-inch (162 cubes/sheet), 1¼-inch (104 cubes/sheet) and 1½-inch
(50 cubes/sheet). All of the sheets measure 10- by 20-inches and fit into
standard 1020 trays. Each sheet is pre-scored on the bottom and top to allow
for easy separation of the cubes at transplant.
The 1-inch Thin-Cut Horticube was developed primarily for
hydroponic lettuce production. This high density configuration accommodates 276
seeds in a standard 1020 tray. Each cube is pre-punched with a dibble hole that
is uniform in depth and has center to center spacing. This allows for the use
of automated seed sowing equipment. Horticubes work equally well with both nutrient
film technique (NFT) and a raft (float) growing system.
Using the North Carolina State University porometer, the 1-inch
Thin-Cut Horticube has a water-holding capacity of 80 percent and air porosity
of 20 percent. A comparable rockwool product, which has grooves at the bottom
of the sheet, has a water-holding capacity of 60 percent and air porosity of 40
Sowing the seed
Horticubes can be seeded dry and do not need to be watered prior
to sowing the seed. Seed can be sown using a vacuum seeder or manually by
placing the seed in the dibble holes. The specially designed hole is tapered to
ensure the seed sets properly in each cube.
After the seed is sown irrigation can be done manually with a hose
and water breaker (i.e., wide fan nozzle) or automatically by passing the
Horticube sheets through a watering tunnel. The sheets should be thoroughly
A single Horticube sheet holds about 4 liters (1 gallon) of water.
However, it takes more than 4 liters of water to ensure total saturation of the
foam because of water channeling through the dibble holes and grooves on the Horticube
sheet. To ensure thorough saturation about 10 liters (2.6 gallons) should be
applied so that the water pours through the bottom of the sheet. As rule of
thumb, water each sheet for 2 minutes at regular tap water pressure.
If the seedlings are going to be irrigated/fertigated by overhead
irrigation, place the Horticube sheets in solid bottom trays with drain holes. Never
use a solid bottom tray without drain holes. If sub-irrigation is going to be
used, place the Horticube sheets in trays that have solid sides and web bottoms.
Like rockwool, the Horticube sheets can be rewetted. Both of these
media should not be allowed to go completely dry between waterings.
Once the Horticubes are thoroughly saturated, the cubes should
stay moist during the course of germination.
Lettuce seed sown in Horticubes does not have to be topdressed
with vermiculite. The seed also does not require a dark treatment for germination.
The best germination usually occurs when the Horticube temperature is below
70°F. The seed usually germinates in two to three days.
and fertilizing seedlings
Generally lettuce seedlings in Horticubes do not require misting
or watering during germination. However, on bright hot summer days consider a
brief misting (5 seconds once a day) on Day 2 and Day 3. Apply clear tap water
with no fertilizer.
Once the lettuce seed has germinated the mist frequency needs to
be adjusted. A typical misting program consists of starting from Day 4 to Day
7, three times a day for 10 seconds. From Day 7 to finish, mist four times a
day for 10 seconds. If the seedlings are going to be either hand-watered or on
a sub-irrigation system, irrigate only once a day.
Start fertilizing the seedlings on Day 4. All of the different
nutrient formulations developed for lettuce production will work with
Horticubes. Growers should customize their specific formulations depending on
water supply, lettuce cultivars, production system, climate and season. The
nutrient solution pH should range from 5.5 to 6. The recommended electrical
conductivity during propagation is 1.0 mS/cm. The recommended electrical
conductivity during production is 1.2 to 2.2 mS/cm.
Lettuce seedlings should be ready to transplant 10 to 14 days
after sowing depending on seasonal climate conditions. During summer months it
takes about 10 days from sowing to transplant and during winter months it takes
about14 days. The criteria for transplant are development of two true leaves
and root penetration through the bottom of the Horticubes.
At transplant the pre-scored sheets can be easily separated into
individual cubes. The easiest way is to break the individual cubes from the top
down along the scoring.
and harvest
Lettuce seedlings in Horticubes transplanted into a NFT or raft
system perform equally well. During production the recommended electrical
conductivity of the nutrient solution should be 1.2 to 2.2 mS/cm. With a NFT
system the water flow rate should be 1 to 1.2 liters per minute. Analysis of
the nutrient solution should be done on a regular basis in order to make
formulation adjustments.
Hydroponically-grown lettuce produced in Horticubes can be harvested
with the root system intact. Leaving the root system intact can help to extend
the shelf life of the lettuce.
For more: Smithers-Oasis
North America; (800) 321-8286; www.oasisgrower.com or Hort Americas, LLC at +1 469 532 2383.
Kuack is a freelance technical writer in Fort Worth, Texas, dkuack@gmail.com.
Dr. Vijay Rapaka is Manager—Grower Research, Smithers-Oasis Co., Kent, Ohio, vrapaka@smithersoasis.com.

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New Horticultural Video Series in Development

Hort Americas has been extremely busy leading up to the Thanksgiving Holiday Weekend.  And lets just say its the good busy, the fun busy!

Last night we shot our first video which will ultimately become a series of educational and information videos geared towards the commercial horticulture and hydroponic industry.  The first video will focus in on the Philips GreenPower LED Production Module and its possible application in the production of ornamental and hydroponic crops.

The New Videos will focus on LED Grow Lights and will star Ms. Abigail Herring!

Hort Americas is also and excited and proud to be working with many of the industry’s top editors.  We are dedicated and focused on helping to build the industry, which makes us thankful (since it is Thanksgiving) for the work of individuals like Annie White of Ball Publishing.  See a sample of Annie’s work here.

Happy Thanksgiving everyone!

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New from the European Greenhouse Industry

 Hort Americas just returned from an excellent visit to The Netherlands and the 2011 HortiFair.

If you get a chance, make sure to visit our Facebook Page and check out our the Photos provided by Dr. Johann Buck and Mr Gerson van’t Wout.  (See alot of interesting photos on the Horticultural LED Grow Lights.)

Also, for those interested in Philips GreenPower LED Grow Lights…click here to see their new Newsletter.

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LED Horticultural Grow Lights Make Propagation Easier and Faster

Rooting cuttings in separate propagation room cuts a week off of production schedule
by David Kuack and Jean-Marc Versolato
Minnesota in the winter
is not the ideal place to try to propagate woody ornamental cuttings. Cold
temperatures and low light conditions make rooting cuttings a real challenge. So
when Jean-Marc Versolato at Bailey Nurseries in St.
Paul, began reading about how European growers were
using LED lights to root cuttings it piqued his interest.
who is the company’s IPM manager for the greenhouses, worked with Philips Horticultural
Lighting and Hort Americas to design a separate propagation room not in the
greenhouses to trial the LED lights.
felt that the LED lights were going to be the next improvement in growing,”
Versolato said. “We started in February 2011 and ran a variety of crops under
the lights. We used three Cannon carts tied together side-by-side to form one
large shelf that can hold up to 15 trays. The trial was conducted in a corner
of our germination room.”
said the germination room was the perfect location for the trial. Located
inside a production building, the room provides a constant 70°F and is equipped
with fogging nozzles in the ceiling. The trial propagation area was partitioned
with black plastic to avoid light contamination from the room’s fluorescent
cuttings only received red and blue light from Philips GreenPower LED production modules. The 5-foot modules, which matched the size of the carts, were
located about 16 inches away from the cuttings.
were taken from a variety of plants in the greenhouses, including Spirea, Celastrus,
Physocarpus and Hydrangea. The cuttings were sprayed with indole-3-butyric acid (IBA) to help initiate rooting. The
cuttings were stuck in 38-cell plastic trays (standard 11- x 21-inch)
containing Preforma rooting plugs. The cart shelves held five flats of each
genus for a total of 15 flats.
fogging nozzles filled the entire room with fog. There cuttings received no direct
water misting or spraying.
using the fog we eliminated droplets from forming on the foliage, which greatly
reduced the chance for Botrytis and loss of cuttings,” Versolato said. “Gravity
caused the fog to descend on the cuttings and the fog kept the cuttings turgid.
LED lights generate heat, but nothing like other lights available for growing.
For this reason the Preforma plugs remained moist and we didn’t need to apply
any additional water.”
cuttings rooted in three to four weeks. Versolato said in the greenhouses the
cuttings root in four to five weeks and occasionally take longer for some
Crops on Cannon carts under fog and Philips LED Grow Lights
Trialing other
the initial propagation trial proved successful, Versolato was looking to try
additional crops. During the summer the company purchased tissue-cultured lilac
rooted three flats of micro-cuttings under the LED lights in three weeks,” Versolato
said. “They required very little grower care whatsoever. The environment in the
propagation chamber was controlled by the LED lights and the fogging nozzles. Also,
no fungicide spray applications were made.”
said winter cutting propagation in the greenhouse can be difficult to manage
because of low light levels, the temperature and the humidity. Based on the
successful results of the lilac trial, Versolato said the company plans to root
25 percent of its French lilacs (Syringa
) cuttings in the propagation room.
January and February we will begin to root the micro-cuttings lilacs in the
room,” he said. “We are probably going to root six to seven varieties, putting
a sample of each one of them under the LED lights to see how they perform.
We’re going to do six carts with three shelves each. Each shelf holds five
trays, for a total of 90 flats under the LED lights. This trial will be our
first multi-layer production attempt.”
pleased with the rooting results under LED lights that he has gotten so far,
Versolato said he thinks there are other factors that are instrumental in the
cuttings rooting faster.
cuttings are being rooted in the Preforma plugs instead of greenhouse growing
media,” he said. “The chamber also has very good temperature and humidity
control. All of these factors put together help to shave seven days off of the
rooting schedule.”
said the propagation room will be used for hard to root crops. The room can
hold 40-50 carts.
are not going to be wasting space in the trial area for crops that are easy to
root in the greenhouses,” he said. “We are looking at a list of a dozen
varieties/species that we would root in the room knowing that they are
difficult to root in the greenhouses. Some of the plants that will be trialed
include Rhus typhina ‘Bailtiger’ Tiger Eyes, Amelanchier and Betula.”
the lilac trial, 15 flats of cuttings were lit by five modules of LED lights.
wanted to be sure that we had enough light for all of the flats,” Versolato
said. “For this coming year the lights are not going to be directly above the
plants or mounted on the carts. We want to be able to move the carts in and out
of the propagation room.”
lights will be mounted on a bracket shelving system and located about 16 inches
above and to the side of the cuttings. Versolato said this will make switching and
handling carts a lot faster and easier.
The right recipe
said the red and blue LED lights come in different recipes depending on what a
grower wants the plants to do, whether it’s develop roots, hasten flower initiation
or speed up time to flower.
recipe that we are using is generic and works with just about any plant we are
trying to propagate,” he said. “It would be too difficult to have a different
recipe for every genus and species that we are growing.”
said Philips can provide growers with the information to tweak the light
wavelength recipe to increase or decrease the amount of red light or blue
Dutch growers, who may be producing acres of Anthurium or another mono crop, it
is easy for them to have a specific light recipe for that one crop,” he said. “But
in our situation where we have many different crops, it would take a lot to
come up with a different recipe for each one of them.”
Finished crop on Cannon carts (multilayer production)
under LED grow lights
Finishing plants
is also planning to do another trial finishing plants in the greenhouse under
LED lights.
has different types of LED lights,” he said. “In addition to the light modules
we used for propagation, Philips also has flowering light bulbs that can be
screwed into regular light fixtures. One helps to promote flowering.
is planning to do a small trial with the flowering LED lights to see if they
help with flower bud initiation on impatiens during early season crop
production. He said the first impatiens crop is grown during the short dark
days of the year and the plants are very slow to develop buds.
though the first crop is currently grown under high intensity discharge lights,
Versolato wants to see what impact the addition of LED lights will have on the plants.
want to try some LED bulbs mixed in with the HID to see if they help to improve
bud count,” he said. “The crop would be put out in the greenhouses around Feb.
23. The light level in the greenhouses in Minnesota during February is very low. We’re
planning to trial about three benches with the LED lights.”
For more: Bailey
Nurseries Inc., www.baileynurseries.com. Hort Americas,
www.hortamericas.com. Philips
Horticultural Lighting, www.philips.com/horti
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com. Jean-Marc Versolato is IPM manager, Bailey Nurseries in St. Paul, Minn.
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Tim Blank and our friends at Future Growing, LLC have done it again! Check out this amazing project they did with the city of Chicago and the Ohare Airport.

Completed in September, we wanted to wait till we had a chance to visit it. So check out the video and then the photos from our visit.

View more videos at: http://nbcchicago.com.
Urban Agriculture and Hydroponics


From Leafy Greens to Herbs to Veggies and Edible Flowers

Farming of the Future

 Please email us with any additional questions on this project or other hydroponic projects around the world.

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Kimitec Launches its North American Website

Its finally up and live! Kimitec.com is the perfect place to go to learn about the latest trials on this organic and non-organic line of fertilizers.  From Amifort to Tundamix, the Kimitec Group (along with the support of American Clay Works in North America) continue to focus increased yield, plant health and vigor.  Please follow this link to learn more about Kimitec Trials in hydroponics, commercial greenhouses and general agriculture.

Visit Hort Americas for additional technical information and to buy your Kimitec today.

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Hort Americas Teams up with Priva for Hydroponic Greenhouse Control Systems

Hort Americas is proud to announce our relationship with PRIVA North America (http://www.priva.ca/en).

“Priva creates innovative solutions for
climate control and process management that make minimal use of
scarce natural resources, such as energy and
water.”  For commercial hydroponic vegetable growers, vertical farmers, urban agriculturalist and greenhouse growers this includes (but does not limit) tools and management strategies for greenhouse/warehouse climate, fertilization, water (incl irrigation), labor, harvest as well other process and processing issues.

Check out this video to learn more about the history of Priva and how they may help your controlled environment agriculture production facility, vertical farm or hydroponic greenhouse.

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Horticoop online magazine BLAD (e-Leaf)

Horticoop B.V. has released the fourth issue of the magazine BLAD or e-Leaf in English.  Check it out!

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Hort Americas is now Certified to Provide Philips LEDs

Hort Americas recently finished its last round of training on Philips GreenPower Horticultural (Hydroponic) LED Product Portfolio. 

This training not only included intense product training, but it also included training on LED applications for:

1.)  Hydroponic Production of Greenhouse Vegetable Crops like Tomatoes, Peppers and Cucumbers
2.)  Hydroponic Production of Greenhouse Leafy Green and Herb Crops
3.)  Greenhouse Ornamentals
4.)  Seed Production
5.)  Tissue Culture
6.)  Growth Chambers and Grow Rooms
7.)  Needs of Research Facilities and Universities
8.)  Multi-layer Production
9.)  Vertical Farming
10.)  Urban Agriculture in Controlled Environments

Next step will be UL certification for the complete line of Philips GreenPower LEDs which are currently being trialed and commercially used in a wide variety of growing facilities around the world.

PlantLab along with many other forward thinkers is working with LEDs.
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Kimitec Organic Fertilizers, perfect for Hydroponically Grown Greenhouse Crops

Not alot of time for a post today, but wanted to put a teaser out there that we are looking at an organic fertilizer that should fit well with Hydroponically Grown Greenhouse Greens, Herbs and Veggies.

Email infohortamericas@gmail.com for details or check out our facebook page for images http://www.facebook.com/pages/Hort-Americas/133476796695370#!/pages/Hort-Americas/133476796695370

Hope everyone is having a good summer!

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LED lighting promising for better light distribution and light as a control


LED lighting promising for better light distribution and light as a control

Most opportunities for LED lighting are in the preliminary application as a control light for better light distribution. This emerged from a meeting of the business platform light on July 7 at the Horticulture. The purpose of the meeting was the latest results from research, both in the floriculture and vegetable cultivation, to share and discuss.

The presentations and discussions with the 40 present researchers, consultants, suppliers and growers, showed that the replacement of SON-T by LED lighting is expected to have a few years away. This by the high costs and too little energy. And while the heat of a SON-T lamp added value, there is no need to replace it with LEDs. On the cost and energy efficiency of the lamp is however working hard by the suppliers.

But there are opportunities to control light and better light distribution over the crop with LEDs. Examples that were discussed were as LED control light in carnation to replace the bulb and LED in a more low-growing tulip. This requires a lot of interest from practice. The price of LED bulbs is still a bottleneck.

Led by as additional exposure with SON-T used between the crops, like tomatoes, is also an added value given. This additional production by the improved light utilization of the crop. The discussion showed that new research is to focus on the above opportunities, but one must closely reflect the practical results that also picked up more easily.

The meeting is with LTO Grow Service, Ministry EL & I Product Board for Horticulture and organized within the framework of the Platform of Light program Greenhouse as Energy Source and is a continuation of previous meetings. This is the innovation and action to significantly reduce CO2 emissions and greatly reduced dependence on fossil energy for the greenhouse in 2020.

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Lettuce Cultivation Using GreenPower LEDs

Urban farming using multilayer production continues to expand in Europe.  What does this mean for urban farmers in the U.S.?

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Update: Veranda O

Earlier this year Veranda O, a biopesticide, was labeled for commercial greenhouse use for food crops.  Recently, there have been some updates to the label and the product’s efficacy which we want to share with you.
Thielaviopsis (Black Root Rot) is now included as a pathogen controlled by Veranda O. 
Thus, the top three pathogens controlled are:
  • Botrytis
  • Rhizoctonia
  • Thielaviopsis
NOTE: Downy mildew control is minimal to ineffective (Straight from OHP).  
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Virtual Grower: A Decision Support Tool

Virtual Grower is a decision support tool for greenhouse growers. Users can build a greenhouse with a variety of materials for roofs and sidewalls, design the greenhouse style, schedule temperature set points throughout the year, and predict heating costs for over 230 sites within the US. Different heating and scheduling scenarios can be predicted with few inputs.

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LEDs and New Opportunities

We at Hort Americas continue to be amazed at what opportunities LEDs may allow for. We know and understand that it is still early in product development, but we also believe it is the way of the future.

We continue to be excited about our relationship with Philips and the opportunity to sell and market their Green Power LEDs (including the Philips Green Power Research Module, Green Power Production Module and the Green Power Flowering Lamp.

Check out this video from 2008. Even back then researchers were starting to see the possibilities…and trust us, these concepts are already working in parts of the world today!

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Pesticide Cheat Sheet

At Hort Americas we continue to add to our plant care product lineup. Therefore, we thought it would benefit our customers to have a reference chart or “cheat sheet”. Please click, download, and/or print this chart for your use. Contact us with any questions or comments.

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