Cornell University is expected to play a major role in the continuing development of the industrial hemp industry in the United States. USDA’s Agriculture Research Service (USDA-ARS) has received $500,000 in federal funding to create the nation’s only industrial hemp germplasm repository or seed bank co-located at Cornell AgriTech in Geneva, N.Y.
Cornell University scientists have developed a computer program, Environmental Monitoring With an Agent-Based Model of listeria EnABLe, to simulate the most likely locations in processing facilities where the food-borne pathogen listeria monocytogenes might be found. Food-borne listeria infects about 1,600 people in the United States each year with about one in five of those infections ending in death.
Continue reading Cornell University computer program helps identify food-borne pathogens
Downy mildew is a major disease on both ornamental and food crops. Whether these crops are grown outdoors or in a controlled environment, environmental conditions, generally cool to moderate temperatures and high humidity, are favorable to downy mildew development. Warm temperatures and high humidity are conducive to powdery mildew development.
Continue reading Controlling basil downy mildew might be as simple as turning on a light
When Hort Americas in Bedford, Texas, started operating as a wholesale horticulture distributor in March 2009, the company had no existing customer base.
Continue reading GLASE consortium aims to improve greenhouse energy efficiency
Most greenhouse growers know the benefits of scouting their crops for pest insects and mites. Scouting can help to identify and minimize pest outbreaks, reduce plant damage and crop losses and save on pesticide and biological control costs.
Continue reading Looking for a better, easier way to do greenhouse IPM?
Hort Americas has retrofitted a 12,000-square-foot greenhouse in Dallas, Texas, for the purpose of studying edible crop production in a variety of hydroponic production systems. The greenhouse is also being used to demonstrate products offered in the company’s online catalog.
Tyler Baras, who is the company’s special projects manager, is overseeing the trialing of leafy greens and herbs in five different production systems.
“We’ve got a deep water culture or raft system using Hort Americas’ fertilizer blend with calcium nitrate and magnesium sulfate,” Baras said. “We are using that same nutrient mix in a nutrient film technique (NFT) system and a capillary mat system.
“I’m using Terra Genesis organic fertilizer in a vertical grow tower. I’m also using the same organic fertilizer for all of the seedling propagation in a flood-and-drain vertical rack.”
Photos courtesy of Tyler Baras, Hort Americas
Baras said the fertilizer recipe he is using in the deep water culture and NFT systems is based on general recommendations from Cornell University and the University of Arizona for leafy greens crop production.
The deep water culture system has been running for three months. The water reservoir for the system is 8,000 gallons.
“Even if water evaporates, since it is such a large body of water, the electrical conductivity (EC) doesn’t really move much,” Baras said. “The EC has been very stable during the three months it has been operating. The reading has barely moved.”
The first trial with the NFT system, which has a reservoir of about 140 gallons, lasted for three months.
“Every week I added an additional 40 gallons of water on average to the NFT reservoir,” Baras said. “The water is evaporating and the salts are accumulating a lot faster in the NFT reservoir than in the deep water culture system. Because the NFT system has a smaller water reservoir, the quicker evaporation rate and the water replacement in the reservoir, has caused the EC to shift a lot more.”
Baras said even with the changes in nutrient levels all of the plants have been performing well.
“I haven’t seen any nutrient deficiencies or toxicities even as the fertilizer recipe has shifted over time. We have been trialing a wide range of crops, including butterhead and romaine lettuces, kale, spring mixes and basil. I’m trialing a lot of crops to figure out when these crops start to be impacted by possibly too much salt accumulation. I haven’t seen anything yet that is alarming.
“One of the things that I have seen over the years working with fertilizers is how wide the acceptable range is for plants to grow well. Between the NFT and deep water culture, the NFT is using half the nitrogen and the plants are performing very similarly. There are recommendations for EC, but none of these fertilizer levels are set. I have some systems that have 20 parts per million phosphorus and some that have 50 ppm and the plants look the same. Most general recommendations say 40-50 ppm. I’ll have some solutions that have 3 ppm iron and others that have 6 ppm iron. It is interesting to see how wide the range is for a lot of these nutrients and the crops are performing the same.”
Baras said he has seen a slowing of plant growth in the NFT system.
“I’m not seeing any deficiencies or toxicities, but the crops have slowed down about a week over the deep water culture,” he said. “Depending on the crop, it’s taking a week longer to reach either the plants’ salable weight or height.
“The slowing in growth could be related to the nutrients. This could be useful information for growers. If they are checking the EC, which may have been 2.3 when a crop was started, if there is a slowing of growth, growers may want to have a water test done. The test could show that the amount of nutrients might be changing.”
During the three months that Baras had been running the NFT system he never flushed the system.
“All that I’ve done with the NFT system is add water and additional fertilizer to maintain a targeted EC,” he said. “One of the goals of the trials is to see what ions are accumulating in the system and to see how long I can run the system before it has to be flushed. When I started the target EC was 2.2-2.3. I still achieved the target EC at three months, but the composition of what was actually in the water changed.
“Originally the NFT fertilizer solution contained about 185 parts per million nitrogen. At the end of the trial the EC was the same but there was only 108 ppm nitrogen in the solution. The calcium concentration was originally 250 ppm and ended at 338 ppm. Sulphur was originally at 80 ppm and rose to 250 ppm. Nutrients have accumulated as the water evaporated. Solely going by the EC meter reading doesn’t tell the full story of what is in that water. The EC of the fertilizer solution that I started with is the same as the EC for the fertilizer solution three months later. The difference is the ions that are making up that ending EC.”
Baras is growing a variety of cut herbs in vertical grow towers. The plants are fertilized with Terra Genesis, a molasses-based organic fertilizer. He said Hort Americas has been hearing from tower growers who are interested in trying to grow organically.
“What we are seeing is the organic fertilizer solution can change a lot over time,” he said. “The fertilizer tank solution matures as time goes on. With the organic fertilizer, the nutrients tend to balance out as the solution is run longer.
“Our city water contains calcium and some magnesium. These elements are actually the nutrients that the organic fertilizer is slightly low in. So as I run the system longer, through the addition of city water, I actually start to see an accumulation of both calcium and magnesium, which actually helps balance out the total fertilizer recipe. The balance of the nutrients has improved over time.
The pH was fairly unstable as it seemed to be going through several biological waves. It was moving rapidly between high and low. As I run the tank solution longer the total alkalinity has increased, which has stabilized it. The biological activity has also started to stabilize. The pH has stabilized in the upper 5 range. For the plants grown organically I have seen deficiencies pop up. The deficiencies were reduced as the fertilizer tank solution ran longer. The deficiencies appear to have balanced out.”
Baras said one noticeable difference between the NFT, deep water and vertical grow towers is how much slower the plants grow in the towers.
“I don’t know what to contribute the slower growth to yet,” he said. “It could be trying to determine the best fertilizer rate for the fertilizer. It could be the crop selection, because most of the crops in the towers are different from what I’m growing in the NFT and deep water culture.
“I’m going to start a deep water culture and NFT trial using organic fertilizer. I’ll have three different organic production systems running simultaneously so I will be able to compare the plant growth in each system. I’ll also be able to compare the growth of the same crops grown with organic or conventional fertilizers.”
Baras said one of the issues that can arise with using organic fertilizer is the development of biofilm in the irrigation lines that can cause emitters to clog.
“I am incorporating a product called TerraBella, which contains beneficial microbes,” he said. “These microbes help mobilize certain nutrients, like phosphorus, which can promote the formation of biofilms. This biofilm buildup is usually more of a problem with high water temperatures.
“About every six weeks I add a booster application of the beneficial microbes depending on the production system. The deep water culture system has a larger reservoir so I am not replacing evaporated water as often. For the other productions systems, like the NFT and grow towers, where I am replacing the water, I am incorporating the beneficials more often. For these systems, the fresh city water that is added dilutes the fertilizer solution. Also, there is chlorine in the city water that possibly could negatively impact some of the beneficial microbes.
For more: Hort Americas, (469) 532-2383; https://hortamericas.com.
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.
The increasing demand for locally-grown vegetables is causing more field vegetable growers, ornamental plant growers and new growers to look at trying to satisfy this market. Cornell University horticulture professor Neil Mattson said he works with all three types of growers.
“I see both vegetable field growers and ornamental greenhouse growers trying to produce lettuce and leafy greens year round,” he said. “Both are quite common. Field vegetable growers are looking for a crop that can generate year-round cash flow. Ornamental growers are looking to fill their greenhouses in the off-season. A lot of ornamental growers no longer produce poinsettias in the fall or spring bulb crops and spring plant propagation that they would normally do in the winter. Growers could have as much as a six-month window when their facilities are not being used.”
Mattson said ornamental growers tend to better understand what it takes to grow a year-round crop.
“Ornamental growers tend to be aware of differences in crops and the problems that can arise,” he said. “They also understand the concept that there is much less light in the winter so they may have to consider using supplemental light. Ornamental growers are usually aware of the high cost of heating a greenhouse year round, especially during the winter.
“In general, field vegetable growers who have greenhouses, may only be using those structures in the spring to produce their transplants. That means they may be used to heating a couple months each year.”
During this year’s Cultivate’16 conference and trade show in Columbus, Ohio, Mattson did a presentation on the year-round production of leafy greens using controlled environment agriculture (CEA). The main environmental conditions growers need to monitor and control include light, temperature and relative humidity.
Mattson said in the northern half of the United States light availability during the winter months is the most difficult environmental issue to deal with when growing plants year round.
“The target light level for lettuce production is 17 moles of light per square meter per day (daily light integral, mol/m2/d) for optimal growth,” he said. “In most parts of the country achieving that target usually isn’t an issue during the summer. In the winter, in the northern part of the country, light levels can be 5 mol/m2/d on average and even 1-3 mol/m2/d is common. That is three to five times less light than what is needed for optimum lettuce growth during the winter.”
Photos courtesy of Neil Mattson, Cornell Univ.
Mattson said supplemental light, using LEDs or high pressure sodium lamps (See the Lamps Needed Calculator, can be provided to deliver higher light levels to increase lettuce biomass. But going above 17 mol/m2/d can cause growers to have issues with tip burn.
“In the case of head lettuce, a grower can go from seed to harvested head (5-6 ounces) in 35 days if there is 17 mol/m2/d. If there is only 8.5 mol/m2/d, it takes the plants twice as long to produce that same biomass.
“For baby leaf greens, if they are seeded and transplanted and grown on for two weeks before harvesting and only receive 8.5 moles of light, the plants will only produce half the yield. If a grower normally harvests 10 ounces per square foot and there is only half the light, the plants will produce only 5 ounces per square foot.”
Mattson said a rule of thumb for New York is a grower can light a 1-acre greenhouse and produce the same yields as not lighting a 3-acre greenhouse to produce the same yields during the winter months.
Lettuce and many other leafy greens are cold tolerant. Mattson said a lot of growers want to grow them cold.
“The Cornell CEA research group proposes that these crops be grown at fairly warm temperatures so that they have the faster 35-day crop cycle,” he said. “This is based on having 17 mol/m2/d and a daily average temperature of 70ºF-75ºF during the day and 65ºF at night.
“During the winter the issue with temperature is paying to heat the greenhouse. It’s easy to control the temperature, growers just have to be willing to crank up the thermostat.”
Mattson said temperature can be really hard to control in southern climates in the U.S.
“Under hot conditions, temperatures in the 80s and 90s, head lettuce is going to bolt prematurely,” he said. “It can be difficult to drop the day temperature low enough to avoid early bolting.”
Beyond trying to reduce the air temperature, research done by the Cornell CEA group has shown that lowering the root zone temperature to 74ºF or less using chilled water can help prevent premature bolting.
“Chilling the root zone temperature allows growers to grow using warmer air temperatures by having the cooler water temperature,” Mattson said. “This is an effective way to chill the plants even when the air temperatures reach the 80s and 90s.”
Mattson said the biggest issue with warmer air temperatures occurs with lettuce and spinach. Warmer temperature and long day conditions can both cause spinach to experience premature bolting. Mattson said warmer temperatures can also promote Pythium root rot on spinach. Spinach is much more susceptible to this water mold than lettuce or other leafy greens.
“Chilling the root zone temperature can help to prevent the disease organism from developing as quickly as at warmer temperatures,” Mattson said. “If the root zone temperature can be kept cool, it won’t completely avoid the Pythium issue, but it will help control it.”
The Cornell CEA group found that the optimum root zone temperature for spinach was 64ºF-65ºF. At this temperature Pythium was deterred, but there was no crop delay. If the root zone temperature is lowered to 62ºF, plant growth is slowed.
Mattson said the relative humidity for lettuce and leafy greens should be between 50-70 percent. He said the lower humidity helps to limit pathogen issues.
“High humidity favors powdery mildew and Botrytis,” he said. “High humidity also favors the physiological disorder tip burn. Tip burn is caused by a calcium deficiency. The higher the relative humidity the less transpiration occurs in the plant resulting in the plant not taking up an adequate amount of calcium.”
Mattson said a relative humidity lower than 50 percent can cause an outer leaf edge burn, which is a physiological disorder.
“This is a different disorder than tip burn caused by calcium deficiency,” Mattson said. “The outer leaves develop lesions where the veins end on the edge of the leaves. The lesions occur where the sap exudes out of the veins and then is reabsorbed by the plant and there is a kind of salt buildup.”
Although fertilization and water quality are not environmental parameters, growers can have issues with both if they don’t monitor them. Lettuce and leafy greens are not particularly heavy feeders compared to other greenhouse vegetables like tomatoes and other vine crops. Mattson said lettuce and leafy greens are relatively forgiving crops when it comes to fertilization.
“Growers need to monitor the nutrient solution every day in regards to pH and electrical conductivity (EC),” he said. “The reason for testing the nutrient solution at least daily is because in hydroponics the nutrient solution pH can change by one or two units in a day.”
Mattson said for container crops like petunia and geranium, pH does not usually change by more than one unit in a week. He said container growers may check the pH every week, and some may only do it every two weeks. But for hydroponics a grower needs to stay on top of changes in pH.
In addition to daily pH and EC monitoring, Mattson said a detailed elemental analysis of the nutrient solution is important.
“Periodically, about every four weeks, growers should send a sample of their nutrient solution to a testing lab to determine if the plants are absorbing nutrients in the proportions the growers expect,” he said. “Certain elements in the solution may decline over time and a grower may have to add more of these elements and less of others.”
Mattson said some systems, like CropKing’s Fertroller, have automated sensors which measure pH and EC in line so it’s a real time measurement. The controller makes the necessary adjustments.
“Typically if a grower is putting high alkalinity water into the system, the pH tends to creep up over time, so the controller automatically adds acid to reach a target pH,” he said. “Likewise, the machine does that with EC too. If the EC is going down because the plants are taking up nutrients, the controller adds fertilizer stock solution to reach a target EC.”
Mattson said iron deficiency due to high pH is the most common nutrient disorder he sees on lettuce and leafy greens. Occasionally magnesium deficiency occurs because the water source contains enough calcium, but not enough magnesium.
“Many fertilizers don’t include calcium and magnesium, so growers can run into issues with magnesium deficiency,” he said. “Basil tends to have a high need for magnesium. We usually recommend basil be provided twice as much magnesium as lettuce.”
Mattson said growers should test their water more frequently to determine if there have been any changes in the alkalinity of the water, including calcium, magnesium and sodium concentrations.
“In the Northeast this summer, we are experiencing a drought,” he said. “I’ve heard from growers who say the EC of their water is going up, which implies that some salt levels are going up. But we don’t know specifically which salts and that would be useful to know what specifically is changing.
“It really depends on their water quality. In particular, EC, alkalinity and whether there are any nutrients in high concentrations, like sodium, can be an issue. It really comes down to how long they are trying to capture and reuse the water. In our Cornell system we have traditionally grown in floating ponds. We use that same water cycle after cycle for several years. We can continually use the same water because we start with deionized water. However, even if the water has fairly low salt levels, using the same water will result in the accumulation of sodium to harmful levels over time.”
For more:
Neil Mattson, Cornell University
School of Integrative Plant Science, Horticulture Section
49D Plant Science
Ithaca, NY 14853
(607) 255-0621
nsm47@cornell.edu
https://hort.cals.cornell.edu/people/neil-mattson
http://www.cornellcea.com
http://www.greenhouse.cornell.edu
Cornell Controlled Environment Agriculture “Hydroponic Lettuce Handbook”
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.
If you missed the e-GRO webinar “Managing Nutrient Solutions for Hydroponic Leafy Greens and Herbs” on Jan. 22, 2016, which was sponsored by Hort Americas, you can still view the webinar on YouTube.
Hydroponic greens and herbs are produced in systems with recirculating nutrient solutions. In order to maintain productive and quality crops, it is important to know how to properly maintain the nutrient solutions. Dr. Chris Currey at Iowa State University and Dr. Neil Mattson at Cornell University discuss strategies for managing pH and EC, formulating nutrient solutions and identifying common nutrient disorders.
Part 1: Common production systems, pH and EC management
Presented by Dr. Chris Currey, Iowa State University
Part 2: Nutrient solution recipes, common nutrient disorders
Present by Dr. Neil Mattson, Cornell University
Maintaining the proper soluble salts (electrical conductivity) level and pH are critical in hydroponic systems like nutrient film technique and floating rafts. While monitoring these properties are important, growers should not overlook the importance that temperature, oxygen level and microbial activity play in the growth of plants in these production systems.
“It’s not as much about maintaining root health as it is about managing the conditions in the rhizosphere, which is the region around the plant roots,” said Rosa Raudales, assistant professor of horticulture and greenhouse extension specialist at the University of Connecticut. “The area around the roots undergoes a lot of biological and chemical activity. Microorganisms in the rhizosphere feed on the exudate of the roots. Managing the rhizosphere and the conditions in the nutrient solution are critical to maintaining plant health.”
Photo courtesy of Rosa Raudales, Univ. of Conn.
While providing the proper air temperature in a greenhouse or controlled environment agriculture system is important, maintaining the optimum root temperature can have a bigger impact on the health and production time of a crop.
“If higher temperatures are maintained in the root zone then the plants are going to lose a lot of energy,” Raudales said. “Temperatures above the optimum in the root zone affect the cell membrane integrity of the roots. A disruption of the cell membranes affects the function of the roots resulting in less nutrient uptake, which affects crop cycles and yields.
“If plants are grown at root temperatures lower than the optimum, the plants grow slower because their metabolism is slower. In the worst case scenario, if freezing temperatures occur then ice crystals could form in the cells resulting in cell leakage and cell disruption.”
Cornell University researchers have conducted studies (http://www.cornellcea.com/attachments/Cornell%20CEA%20Lettuce%20Handbook%20.pdf) to identify the specific temperatures that are ideal for hydroponically-grown vegetables.
“Cornell researchers found the temperature of the nutrient solution had a greater effect than the air temperature,” Raudales said. “Lettuce plants exposed to air temperatures ranging between17ºC (62.6ºF) and 31ºC (87.8ºF) had consistent yields as long as the nutrient solution had a consistent temperature of 24ºC (75.2ºF). This research was done in the 1990s, but it still has application today.
“Cornell researchers did a similar study with spinach and they found the optimum root temperature was 22ºC (72ºF). They tested air temperatures ranging from 16ºC to 33ºC (60.8ºF-91.4ºF) and they found as long as the root temperature was 22ºC, the air temperature could be in that range and plants still produced optimum yields. For tomatoes the optimum root temperature is 25ºC (77ºF).”
Raudales said growers who are producing hydroponic leafy greens like lettuce and spinach have the option of installing a water heater to maintain the optimum root temperatures.
“It is easier and less expensive to heat the nutrient solution than to keep the whole greenhouse warm,” she said. “Heating the greenhouse does not make economic sense, when the research indicates that the temperature of the nutrient solution is a more important factor. If a grower is producing lettuce and spinach, which can tolerate lower air temperatures, it makes sense to run the greenhouses cooler and to install a water heater to adjust the nutrient solution temperature.”
Raudales said the dissolved oxygen level in a hydroponic solution needs to be maintained so respiration can occur in the roots.
“When oxygen levels are low in the root zone, the roots do not take up the nutrients required for growth,” she said. “Low oxygen levels cause increased ethylene production in the roots. If there are higher ethylene levels in the roots then the roots start to mature and die. The more oxygen present, the better the nutrient uptake and the better the root system.”
Raudales said there is also an inverse relationship between the oxygen level and solution temperature.
“If the root zone temperature is high, then the oxygen level is going to go down,” she said. “This is another reason why the root zone temperature is so important. The optimum oxygen level should be greater or equal to 6 parts per million of dissolved oxygen in the root zone. Plants should be able to handle 6-10 ppm without any problems.”
Raudales said growers who are using nutrient film technique systems typically don’t need to do any type of aeration. The movement caused by the flow of the water is usually enough to keep the oxygen level high enough in the solution.
Raudales said growers who are using floating rafts usually incorporate some type of oxygen-generating system.
“There are different ways of oxygenating the water,” she said. “One is aerating the water where air is being pumped into the water. Air is not pure oxygen, but it contains enough oxygen for what is needed in the hydroponic solution.”
Raudales said another reason for maintaining a high oxygen level in the hydroponic solution is the effect it can have on pathogenic fungal zoospores.
“If there is more oxygen, then zoospores don’t survive as well,” she said. “Zoospores don’t want completely anaerobic conditions, but they do better in conditions where there is less oxygen.
Pathogens of concern include Phytophthora, Pythium, Thielaviopsis basicola and Xanthomonas.
“Growers should try to keep the oxygen level high. If there are warmer temperatures, then there are lower oxygen levels. When there are lower oxygen levels the plants are not as healthy and more zoospores tend to survive. This is one of the reasons why there tends to be more disease issues during the summer than during the winter.”
Raudales said growers who are using floating rafts should be measuring the oxygen level regularly. Meters for measuring dissolved oxygen look like pH meters and are simple to operate.
Raudales said beneficial microbes are present naturally in water. Commercial products with beneficial microbes can also be incorporated into the hydroponic solution.
“Growers who are using the floating rafts tend to treat the nutrient solution like gold,” she said.
“They don’t want to replace it because they have a solution which is very high in beneficial microbes. Growers can inoculate the nutrient solution with a commercial biocontrol product or they can allow the good microbes to build up with time.
“As long as growers maintain the other parameters at optimum levels, including root temperature, pH, nutrients and oxygen levels, there typically isn’t a problem with diseases. This is very comparable to what happens with plants grown in substrates. The microbes build up naturally in the water just like in a substrate. These microbes feed on the exudates of the roots.
They need carbon sources that they wouldn’t get just from the nutrient solution. The system has to be clean, but it doesn’t have to be clean to the point of having to start with a fresh solution every time a new crop is planted.”
For more: Rosa Raudales, University of Connecticut, Department of Plant Science and Landscape Architecture; (860) 486-6043; rosa.raudales@uconn.edu; http://www.greenhouse.uconn.edu.
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.
U.S. Centers for Disease Control and Prevention estimates 48 million people are sickened each year by foodborne pathogens. Of those people about 128,000 are hospitalized and 3,000 die each year.
On Nov. 13, 2015, U.S. Food and Drug Administration finalized three rules of the Food Safety Modernization Act. The purpose of FSMA, according to a FDA press release is to prevent foodborne illness “that, for the first time, establish enforceable safety standards for produce farms and makes importers accountable for verifying that imported food meets U.S. safety standards.” FDA said FSMA’s “final rules will help produce farmers and food importers take steps to prevent problems before they occur.”
“The recent multistate outbreak of Salmonella in imported cucumbers that has killed four Americans, hospitalized 157 and sickened hundreds more, is exactly the kind of outbreak these rules can help prevent,” said Michael Taylor, FDA deputy commissioner for foods and veterinary medicine. “The FDA is working with partners across the government and industry to prevent foodborne outbreaks. The rules will help better protect consumers from foodborne illness and strengthen their confidence that modern preventive practices are in place, no matter where in the world the food is produced.”
The three final rules released by FDA in November are the Produce Safety rule, the Foreign Supplier Verification Programs rule and the Accredited Third-Party Certification rule. FDA has finalized five of the seven major rules that implement the core of FSMA. In September 2015, FDA released the Preventive Controls for Human Food rule, which mandates preventive practices in food processing and storage facilities.
The Produce Safety rule is the one rule that should have the biggest impact on outdoor farmers, greenhouse growers and controlled environment agriculture (CEA) growers. FDA used public comments and input collected during farm visits, meetings and listening sessions to develop a rule it says aims at reducing contamination risk while providing flexibility for farmers and growers.
This rule “establishes science-based standards for growing, harvesting, packing and holding produce that are designed to work effectively for food safety across the wide diversity of produce farms.” The rule’s standards include “requirements for water quality, employee health and hygiene, wild and domesticated animals, biological soil amendments of animal origin such as compost and manure, equipment, tools and buildings.” The rule’s standards have been designed to “help minimize the risk of serious illness or death from consumption of contaminated produce.”
One crop that the rule specifically addresses is the production of sprouts, which have been frequently associated with illness outbreaks. FDA reports that between 1996 and 2014, there were 43 outbreaks, 2,405 illnesses, 171 hospitalizations and three deaths associated with sprouts. Among the outbreaks was the first documented case of Listeria monocytogenes associated with sprouts in the United States. This crop is particularly vulnerable to microbial contamination because of the warm, moist conditions in which they are produced.
The earliest compliance date for the Produce Safety rule for some farms is two year after the effective date of the final rule. There are exemptions to the rule for some producers. These include farms that have an average annual value of produce sold during the previous three-year period of $25,000 or less. Also to be eligible for a qualified exemption, the farm must meet two requirements:
1. The farm must have food sales averaging less than $500,000 per year during the previous three years.
2. The farm’s sales to qualified end-users must exceed sales to all others combined during the previous three years. A qualified end-user is either (a) the consumer of the food or (b) a restaurant or retail food establishment that is located in the same state or the same Indian reservation as the farm or not more than 275 miles away.
Dr. Elizabeth Bihn, director of the Produce Safety Alliance at Cornell University, said prior to FSMA, buyer demand has been the primary driver for implementation of food safety practices. “Consumers are buyers, but they are not protecting a name brand like Kroger or Wegmans or Wal-Mart,” Bihn said. “These companies are protecting their brands. They are going to have much higher stipulations for food safety then the consumers at farmers markets. There is some consumer demand for increased accountability for food safety, but it’s not as big a driver as the retail buyers’ demand. This includes most large food retailers.”
Bihn said greenhouse vegetable growers and CEA growers may receive added pressure from buyers to follow FSMA whether or not they are exempt from it.
“If a buyer tells a grower, “I’m not buying your produce unless you have a third party audit,” and the grower wants that company’s account, then the grower is going to do the audit,” Bihn said. “Legally a grower may be exempt from the regulation, but a buyer may say it doesn’t matter, the grower will still have to meet the regulation. There are still going to be markets that don’t require growers to meet the regulation if their operations are exempt from it. If you are a greenhouse grower who sells to a market that’s not requiring compliance with FSMA and you are exempt from the regulation, you may not have to do anything related to the regulation. Also, I can see third party audits, like the Harmonized GAPs audit, being updated to align with the rules to make sure that growers who have audits done meet the federal regulations as well.”
Even before the final rules were released, Bihn said she is receiving increased inquiries from greenhouse growers about food safety. “Greenhouse growers are trying to decide if they are subject to FSMA rules and how the required practices might fit with what they do with their greenhouses,” she said. “They are trying to figure out if they need to be concerned with meeting food safety regulations. They are going to be in the same situation as field farmers and asking the same questions. Are buyers asking the growers to meet the regulations? Greenhouse growers not subject to the regulations could easily get pushed into following the regulations if their buyers tell them in order to do business with them, the growers must follow the regulations.”
Bihn said her job is to help guide produce growers, whether they are field farmers, urban farmers, greenhouse growers or CEA growers, toward implementing food safety practices.
“Initially there may be frustration, hostility and denial,” she said. “All of those things will occur when growers first hear what they have to do. When they finally sit down and start to learn something about food safety and start to ask how can I fix this, then they start to make progress really fast.
“I love farmers who question everything. They don’t understand why doing something is a risk. They tell me I’ve never killed anyone so what’s the problem. That’s the engagement that I need to get them to think about it. They need to get to where they understand all farms can have produce safety risks and admit that they need to learn something about food safety so that they can make adjustments within their operations and put practices in place to reduce the risks.”
Bihn said she has been encouraging Cornell students majoring in horticulture to get a minor in food science. She has also been encouraging students majoring in food science who are interested in produce safety to get a minor in horticultural production.
“There are food science students who have no idea how farms operate,” she said. “Unfortunately this sometimes results in food science professionals offering ideas for problem solving that may not be doable.”
Bihn said that food safety has traditionally been housed with the food science departments and crop production has been housed with the horticulture department.
“It’s time for there to be some cross pollination between these two departments,” she said. “It has been slow to happen. We now have a Masters of Professional Studies degree at Cornell that merges horticulture and food science. There are jobs out there, but they are difficult to fill because there are people who know production or there are people who know food pathogens, but there are very few people who know both.”
Bihn said she has received requests from her horticulture colleagues at Cornell to give guest lectures on food safety and to collaborate on publications about incorporating food safety guidelines into field publications.
“The fruit and vegetable industry as a whole is certainly saying food safety is something that we need to be incorporating,” she said.
For more: Dr. Elizabeth Bihn, Cornell University, Department of Food Science; (315) 787-2625; eab38@cornell.edu.
Produce Safety Alliance, http://www.
National Good Agricultural Practices Program, http://www.gaps.cornell.edu.
David Kuack is a freelance technical writer in Fort Worth, Texas; dkuack@gmail.com.
Continue reading High tunnels enable growers to increase production of high-value berries
Greenhouse lettuce can be a successful container or
hydroponic crop for ornamental plant growers looking to give edibles a try.
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| Ornamental plant growers interested in growing edible crops may want to try lettuce. It can be produced in containers with a growing medium or hydroponically in troughs or a float system (pictured). Photos courtesy of Cornell University |
Mattson said. “Grown as a
container crop, lettuce is relatively similar to petunia. However, lettuce has somewhat
greater calcium needs. Growers can produce a relatively good crop of lettuce in
containers, if they use a complete fertilizer at a moderate strength of 150
parts per million nitrogen.”
Leaf tipburn is a physiological disorder that can occur
when growing greenhouse lettuce. It can greatly impact the salability of a
crop.
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| Calcium tipburn in lettuce is not a result of a lack of calcium supplied to the plants, but an inability of the plants to transport enough calcium to the young leaves. |
Mattson has been able to grow a relatively good crop of
container-grown lettuce using granular organic fertilizers incorporated into
the growing medium.
One strategy that Mattson recommends growers do periodically
is to monitor the electrical conductivity (EC) and pH levels.
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| Monitoring electrical conductivity (EC) can help avoid under fertilizing lettuce plants, which show yellow lower leaves caused by nitrogen deficiency. |
Mattson said light and temperature are going to be the
drivers for how long it takes to finish a lettuce crop. Whether a grower is
producing the crop in containers with growing medium or hydroponically
shouldn’t have any effect on the length of production.
For more: Neil
Mattson, Cornell University, School of Integrative Plant Science; (607)
255-0621; nsm47@cornell.edu.
Visit our corporate website at https://hortamericas.com
Bill Phillimore, executive vice president at Paramount
Farming Co. in Shafter, Calif., spoke at this year’s Seeley Summit which
focused on water. Phillimore, whose company is a producer of a variety of tree
crops, discussed the impact the drought has had on water availability and
trying to operate under severe water restrictions.
 |
|
Bill Phillimore, executive vice president at
Paramount Farming Co., whose responsibilities include water and power issues, knows firsthand the effects drought can have on an agricultural producer. |
Paramount is farming more than 100,000 acres in 2014 with
a combination of citrus, almonds, pistachios and pomegranates.
We have managed to secure sufficient water for these
crops in 2014, but at very considerable expense. In some instances we are
applying less irrigation water than we would optimally prefer.
We have never faced water restrictions this severe in
California previously.
Due to our size our water comes from a number of
different sources, including the State Water Project, exchange contractors and
the Kern River. In almost all instances, this water is supplemented by
groundwater which is being particularly heavily used in 2014.
All our property is irrigated with drip or micro
sprinklers as it has been for more than the last 20 years. The drought has not
changed our methods of irrigation because we made the change to more efficient,
practical systems some years ago.
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|
Paramount Farming Co. is farming more than 100,000 acres
this year with a combination of citrus, almonds, pistachios and pomegranates. |
We hope that we have timed the application of water,
especially in those crops where there has been reduced amounts, so that there
has been no negative effect on plants or yields. Although in determining the
schedule we have relied heavily on previous experiments conducted on our
property, this is obviously being done on a far greater scale and thus it is
not currently easy to assess either the long or short term effects.
In Kern County, where we have the majority of our
acreage, we share climate with the rest of the Central Valley in California
with some slightly greater extremes and different soil conditions. All these
environmental factors, which allow dormancy in the winter, but not usually
extreme low temperatures, and hot, dry summers, are particularly suited to the
production of pistachios, almonds, table grapes, carrots and citrus.
Most precipitation in California occurs in the north of the
state while the majority of the usage, both urban and agricultural, occurs
south of the Sacramento-San Joaquin River Delta. One of the greatest challenges
that California has is how to move water through the delta to southern
California without environmental damage.
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|
Applications of reduced amounts of water to Paramount’s crops
are based on experiments conducted at the farm aimed at avoiding any negative effects on the plants or their yields. |
I did express concern during the Seeley Summit that all
trade organizations do an adequate job of representing their members because
they do not always understand all the issues that they are being asked to
address. These organizations often spend too little time consulting their
members, especially when the organizations are covering a broad range of issues.
I do believe that all farmers of whatever size need to be conscious of this
fact and that unfortunately there is no substitute for their personal
involvement.
For more:
Paramount Farming Co., (661) 399-4456; http://www.paramountfarming.com.
Visit our corporate website at https://hortamericas.com.
U.S. university floriculture professors and extension
specialists have collaborated to bring the floriculture industry an extensive
and thorough information resource.
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| The American Society for Horticultural Science presented the developers of the e-GRO website with its Extension Educational Materials Award |
The two-year-old e-GRO: Electronic Grower Resources
Online website was the brainchild of Brian Krug, extension greenhouse and
horticulture specialist at University of New Hampshire, Brian Whipker, extension
floriculture specialist at North Carolina State University, Roberto Lopez,
floriculture extension specialist at Purdue University, and Nora Catlin, floriculture
specialist at Cornell Cooperative Extension of Suffolk County.
Krug said that although there is a tentative schedule as
to what is going to be written about during a specific week, the topic and
author can change depending on what growers may be dealing with. The
newsletters cover a variety of grower-related issues including disease and pest
management and environmental, physiological and nutritional disorders being
observed in commercial greenhouses.
Another part of the website is e-GRO University. This
section was developed by Krug, Whipker, Lopez, Kansas State University
floriculture professor Kim Williams, Kansas State ornamental and horticultural entomologist
Ray Cloyd and Cornell University senior extension associate and plant
pathologist Margery Daughtrey. e-GRO University is the second phase of the
website which includes over 60 videos that cover the basics of greenhouse
production. The videos are divided up into five different sections: greenhouse
management, nutrition management, growth management, insects and mites, and diseases.
e-GRO University has been funded by the Gloeckner Foundation for two years.
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| e-GRO University provides a Greenhouse 101 curriculum that covers basic information for greenhouse management and production. |
“For e-GRO University we developed a Greenhouse 101
curriculum that provides basic information for greenhouse management and
production,” Krug said. “It is information that would be comparable to a
freshmen and sophomore college course program. Our goal was to provide an
educational resource for people who work in the industry who didn’t receive a
formal education in greenhouse production. If you are grower in a greenhouse without
the formal training or education, this program allows a person to get a handle
on some of the basics on nutrition, insects and diseases. A person can choose
to listen to any of the videos, which run 20 minutes or less. Most of the
information is basic concepts so it is not going to be changing.”
Other resources available to visitors of the e-GRO
website include:
2. e-GRO Volume One: Poinsettia
3. e-GRO Alert Volume Two
4. e-GRO Volume Three: Primula
5. e-GRO Alert Volume Four: Sclerotinia
For more:
Brian Krug, (603) 862-0155; brian.krug@unh.edu.
Visit our corporate website at https://hortamericas.com
Continue reading Using Supplemental Lighting in Greenhouse Vegetable Crops
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