Louis (“Lou”) DeMont Albright, 81, of Ithaca, NY passed away March 26, 2022. Lou was born December 31, 1940 in Ithaca NY, to Richard and Catherine Albright, and grew up in Newfield NY, graduating from Newfield High School in 1958. He attended Cornell University, receiving a Bachelor of Science in Agricultural Engineering (1963), Master of Science in Food Science (1965) and PhD in Agricultural Engineering (1972). He served in the US Army from 1965 to 1968.  After receiving his PhD, he took a tenure-track position at UC Davis, before returning to Cornell in 1974, where he taught until retiring in 2010. In 1994 he was named a Fellow of the American Society of Agricultural Engineers. He was a dedicated researcher, teacher and advisor, receiving numerous teaching awards, including Cornell’s Weiss Presidential Fellowship.  He is survived by his wife Marilyn, sister Janice, son Adam and daughter Amy, and step-daughters Darla and Rhonda. In addition to family and research, he had a lifelong devotion to nature and the outdoors, and enjoyed bonsai and stonecraft.

A small service will be held at Woodlawn Cemetery in Newfield, NY at 1pm Friday, April 22. The family suggests that those who would like to make a donation in Lou’s memory kindly consider the Michael J. Fox Foundation for Parkinson’s Research at www.michaeljfox.org.

Controlled Environment Agriculture (CEA) is an advanced and intensive form of hydroponically-based agriculture where plants grow within a controlled environment to optimize horticultural practices.

CEA techniques are not simpler than older systems for growing plants. Indeed, they demand sound knowledge of chemistry, horticulture, engineering, plant physiology, plant pathology, computers and entomology. A wide range of skills as well as a natural inclination to attend to details are necessary for a person to operate a successful CEA production in either a research or commercial setting.

Importance

Today’s consumers increasingly demand a diet that includes fresh, high-quality vegetables free of pesticides and other agricultural chemicals. Local production is also a major factor when fresh vegetables are purchased. In many regions of the United States and the world, climate makes it impossible to meet this need year-round with only local produce. Produce imported into the United States may be from other regions of the country (California, Florida, and Texas are major exporting states) and from other countries (primarily Mexico, Netherlands, and Israel).

When fresh produce is transported great distances there can be a significant loss of quality. Furthermore, energy requirements for transport can be significant. Local production in CEA facilities can also require significant energy inputs for heating, venting, and possibly supplemental lighting. Studies have suggested the (non-solar) energy required to grow and transport fresh produce at least 1000 miles is equivalent to the energy required for local production within CEA facilities in cold and cloudy climates such as the Northeast and upper Midwest.

Transportation relies on liquid fuels, the price of which is predicted to rise faster than the general inflation rate. Production in CEA facilities relies on electricity and natural gas, the prices of which are predicted to rise no faster than inflation. These factors suggest CEA production of fresh vegetables can become a significantly greater component of commercial agriculture in the coming decades.

Benefits to Consumers

Well-managed, local CEA operations can provide fresh produce (as well as flowers or pharmaceutical plants) of high quality and free of agriculture chemicals. Furthermore, CEA facilities can be closed in terms of discharging liquids either to surface or ground waters. CEA facilities can also be located in urbanized areas, thus not requiring the conversion of open or agricultural land to greenhouses. CEA facilities add to local tax bases and bring net income to a community.

Benefits to Agriculture

Certain sectors of the agricultural industry face increasingly difficult economic outlooks. This is especially true of the dairy industry. Diversification is one means to improve the economic stability of small farmers and CEA is an option to diversify. Furthermore, many family farms can not be divided among two or more children wishing to remain in agriculture. Adding a robust CEA facility provides the opportunity for more than one child to remain.

Benefits to Utilities

The two most important environmental variables for growing plants are temperature and light. Both parameters must be controlled to be uniform from one location to another in a greenhouse, and consistent from day to day. The only method available to achieve consistency is to use supplemental lighting. Where the climate is cloudy, electricity needed yearly for suitable lighting can be as much as one hundred kilowatt-hours per square foot of lighted area. This load is primarily during off-peak hours and can be interrupted for short periods. These features should make CEA electricity loads highly attractive to many local utilities.

A Brief History of CEA

CEA, or Controlled Environment Agriculture is a combination of horticultural and engineering techniques that optimize crop production, crop quality, and production efficiency (Albright, 1990). Dalrymple (1973) found the earliest known CEA production in recorded history was mandated by the Roman Emperor, Tiberius Caesar (between 14 – 37 A.D.). Caesar’s doctor told him he needed a cucumber a day for good health. So, movable plant beds were placed outside during favorable weather, and brought indoors during unfavorable weather. During winter, on sunny days, the beds were covered with a frame glazed with transparent stone (mica) and brought outdoors.

Greenhouse production of food (again cucumbers) is next recorded in 1597. In the 1500’s lantern covers were placed over small areas of ground and used to force vegetables. By 1670 greenhouse structures similar to those used today were described. These early European greenhouses utilized wood frames with either glass or oiled paper (Dalrymple, 1973).

In the United States, greenhouses were present near the time of the American Revolution. This included George Washington’s conservatory at Mount Vernon, which was built in 1780. The heat source for early American greenhouses was usually from heat produced by the decomposition of manure (Dalrymple, 1973). By 1900, most greenhouse heat came from heated-water systems. Efficient boilers and improved heating systems were developed by the turn of the 20th century (Langhans, 1990). However, a critical component to year-round success was still missing.

In 1887, growers in the United States were advised in The American Florist to refrain from growing tomatoes in greenhouses until April, because “You can’t make sunshine” (Starr, 1887). Making “sunshine” had become possible with the invention of the incandescent lamp by Thomas Edison in 1879, but widespread use of electric lamps did not occur until the early 1900’s after many small power plants and generators were in place (World Book Encyclopedia, 1997).

The first scientific experimentation on the influence of supplemental light on a greenhouse crop was performed at Cornell University by Liberty Hyde Bailey in 1889 (Dalrymple, 1973; Bailey, 1891). The practice was termed “Electro-culture”, and was documented as significantly improving crop production, but was not considered economically feasible for food production. Even today, only crops with relatively high monetary value (e.g., spinach, raspberries, tomato, specialty lettuce crops) can justify the additional production cost from the use of supplemental electric light. In the 1960’s, work at the ARS Phyto-Engineering Laboratory, USDA in Beltsville, MD showed significant increases in lettuce, tomato and cucumber seedling growth through the use of plant growth chambers (Krizek, 1968).

From the mid 1980’s through the late 1990’s, NASA conducted plant growth chamber research in the Kennedy Space Center Biomass Production Chamber, providing state of the art levels of environmental control and monitoring of food crop production in this Martian Base prototype facility. Plant research in the NASA Biomass Production Chamber has provided evidence that the nutritive value of food crops can be as good or better than field grown crops (Wheeler et al, 1996; Wheeler et al, 1997). Other researchers have noted the increased nutritional benefits of CEA crops (McKeehen et al, 1996; Mitchell et al., 1996; Nielson et al., 1995; Johnson, 2000).

In 1999, the Cornell University CEA Program broke ground on the first commercial scale CEA prototype lettuce production facility in Ithaca, New York. The facility has a production capacity of 1245 heads of high-quality lettuce per day. The prototype facility represents the transition stage from CEA Research to commercial scale production.

Cornell CEA today

Cornell’s current CEA collaborations are housed in the Horticulture Section of the School of Integrative Plant Science in the College of Agriculture and Life Sciences, under the leadership of Neil Mattson. One major effort has been the formation of GLASE—the Greenhouse Lighting and Systems Engineering Consortium

The GLASE Consortium was established in 2017 by Cornell University and Rensselaer Polytechnic Institute, and is supported by the New York State Energy Research and Development Authority (NYSERDA) and by industry partners. GLASE develops advanced greenhouse lighting and control systems tailored to the needs of specific greenhouse and indoors cultivated crops. The consortium’s work extends to all areas of the CEA lighting environment, integrating advances in LED light engineering, carbon dioxide enrichment, and lighting control systems.

The public-private collaboration merges leading-edge academic research with the marketplace expertise of industry practitioners. GLASE partners are CEA growers, horticulturists, produce buyers, plant physiologists, lighting manufacturers, and agriculture engineers—all committed to pioneering and commercializing breakthrough greenhouse technology.

For more information on controlled environment agriculture you can post questions below or contact Professor Neil Mattson or Erico Mattos at Cornell University.

What are the critical skill sets, and how can we create a larger pipeline of individuals trained in these skills so that they can contribute to CEA business success?

At Cornell University, a group led by Professor Anu Rangarajan (Director, Small Farms Program) seeks to provide answers as part of a National Science Foundation-funded research project on CEA Viability in Metro Areas.

Rangarajan’s team has conducted extensive research to date in order to understand the workforce needs of the hydroponics industry, including greenhouses and indoor vertical farms—and the research continues.

With the long-term goal of creating robust curricula for training CEA employees in mind, a team from Cornell University conducted many in-depth interviews with professional CEA growers in 2018 and 2019.

The team then organized a workshop, in consultation with The Ohio State and Agritecture Consulting, that invited a focus group of CEA operations managers to model in detail the diverse activities that they perform on the job.

The resulting chart is a detailed, peer-reviewed list of duties (responsibilities) and tasks (activities, skills) that describe the work of the expert Indoor Farm Operations Manager.

The chart is currently being reviewed by peer growers worldwide, who are asked to verify how important each skill is, and how frequently it is conducted.

Based on this input, the Indoor Farm Operations Manager chart will be used as a starting point for prioritizing future CEA training modules. After that, a deeper analysis of key individual skills will be conducted in order to translate the foundational research into a teachable vocational curriculum.

Right now, however, Rangarajan’s team is actively seeking more responses to the verification survey.

“We need your help,” she emphasizes, speaking to professional CEA growers. “We want to learn your priorities for a CEA curriculum that will enhance the skills of current or future employees.”

The survey takes approximately thirty minutes to complete and can be completely anonymously. CEA growers who complete the survey will also be provided with an Amazon gift card for $25 as a token of appreciation, although they must provide their names and email addresses in order to receive this gift.

To take the survey, register here. The Cornell team will send a survey link directly from Qualtrics.

As Rangarajan notes, “Grower input will help us prioritize the core education and training relevant to indoor agriculture,” helping provide the industry with the skilled workforce it will need to scale.

For more information about this study regarding the future of the CEA workforce, please contact project lead Anu Rangarajan (ar47@cornell.edu) or research associate Wythe Marschall (wmarschall@fas.harvard.edu).

Lighting approaches to maximize profits

Date: April 16, 2020
Time: 2 p.m. – 3 p.m. EST
Presented by: Marc van Iersel

Supplemental lighting is often necessary for year-round greenhouse production of ornamentals and vegetables. However, the cost of providing supplemental light is high. It is therefore important that supplemental light is provided in a way that provides the greatest benefits for the crop, at the lowest possible price. To do so, it is important to understand the cost of providing supplemental light as well as how plants use that light. Accurate weather predictions can help minimize the risk of providing more excess light than is required by a specific crop. Learn how to account for these factors to help grow high-quality, profitable crops.

Registration link: https://cornell.zoom.us/webinar/register/WN_GaJLKaKiRQGoiD4Ro7JKeQ

Webinar title: Off-season strawberry production under controlled environments

Date: November 21, 2019

Time: 2 p.m. – 3 p.m. EST

Presented by: Dr. Chieri Kubota

Register now at https://cornell.zoom.us/webinar/register/WN_BW_p9oDyS7Cmx1DllSCLbA

Date: October 25, 2019
Time: 12 p.m. – 1 p.m. EDT
Presented by: Neil Mattson and Jonathan Allred

Click here to register!

Carbon dioxide enrichment has long been known as a tool to boost greenhouse crop yield but the benefits depend on the crop and production environment especially light. In this webinar, Cornell University researchers will discuss:

• The basics of greenhouse CO2 enrichment.
• Current research underway to determine response of tomatoes and strawberries on light and CO2.
• Experimental results from two years of studies on day-neutral strawberry cultivar selection and response to HPS and LED supplemental lighting.

The GLASE Webinar Series features the latest technological innovations and best practices in the controlled environment agriculture (CEA) industry providing the participants an opportunity to discover new solutions and to connect with industry experts. The webinars are free.

July 25 • 2-3 p.m. EDT – REGISTER HERE
Supplemental greenhouse lighting during propagation
Presented by Erik Runkle and Roberto Lopez, Michigan State University

Aug. 22 • 2-3 p.m. EDT – REGISTER HERE
National greenhouse database
Presented by Erico Mattos, GLASE

Sept. 26 • 2-3 p.m. EDT – REGISTER HERE
Humidity control in greenhouses and other indoor plant environments
Presented by Nadia Sabeh, Dr. Greenhouse, Inc

Oct. 24 • 2-3 p.m. EDT – REGISTER HERE
Strawberry and tomato responses to light and CO₂ control
Presented by Neil Mattson and Jonathan Allred, Cornell University

Nov. 21 • 2-3 p.m. EDT – REGISTER HERE
Off-season strawberry production under controlled environments
Presented by Chieri Kubota, Ohio State University

Dec. 2019
LED basics applied to horticulture lighting systems
Presented by Bob Karlicek, Center for. Lighting Enabled Systems and Applications

Jan. 2020
Horticultural lighting systems energy-savings calculations
Presented by Neil Mattson, Cornell University, and A.J. Both, Rutgers University

Feb. 2020
Influence of temperature and daily light integral on culinary herb production
Presented by Roberto Lopez and Kellie Walters, Michigan State University

March 2020
Lighting approaches to maximizing profits
Presented by Marc van Iersel, University of Georgia

Technical Articles 

The GLASE Technical Articles series delivers the latest GLASE research updates. In a series of 10 publications researchers from Cornell University, Rensselaer Polytechnic Institute and Rutgers University will cover a wide range of applied CEA technologies including new LED lighting systems, integrated CEA control systems, measurement standards, energy modeling and commercial case studies. The articles will be published on a monthly basis.

• July 2019 – New horticultural Research LED lights  
• Aug. 2019 – Light and shade system implementation (LASSI)  
• Sept. 2019 – Light measurements and distribution in tall canopy crops
• Oct. 2019 – A new greenhouse light spectral acquisition system
• Nov. 2019 – Plant responses to integrated light and CO₂ control
• Dec. 2020 – Horticultural lighting standards
• Jan. 2020 –  Remote chlorophyll fluorescence  detection system
• Feb. 2020 – Controlled environment agriculture (CEA) energy modeling
• March 2020 – A modified infra red gas analyses for light response curves
• April 2020 – GLASE commercial pilots – A case study

One of the many challenges of tomato (Solanum lycopersicum L.) and kale (Brassica oleracea) greenhouse growers is the management of edema (oedema). Often described as intumescence or enations, edema is an abiotic-induced complication that develops at different levels of intensity
depending on the cultivar and, in some cases, between individual plants.

Symptoms

Edema is often described as a blister or callus-like formation that forms predominately on the bottom of leaves (Figure 1).

This swelling is the result of the epidermal layer on the leaf expanding due to cellular elongation, which eventually burst as cells reach their limits of expansion.

The resulting damage on the bottom-side of the leaf can be characterized by dark brown, tan, or even yellow necrotic tissue on the surface of the leaf that expands past the original location of the blister as a scab-like injury (Figure 2). On the upper side, necrotic spots mark the location of the ruptured intumescence below, while the surrounding tissue is generally
chlorotic (Figure 3). Tissue affected by edema is brittle, with the leaf structure cracking under gentle pressure by the fingers. Extensive edema can severely decrease the leaf’s photosynthetic capability and lead to senescence (Figure 4).

Causes

The cause of edema can be linked to a variety of environmental conditions. The long-standing suggested cause of intumescence is the buildup of excess
moisture in the root medium paired with conditions favorable to low transpiration (i.e. high humidity). In a study conducted by Kansas State in 20091, it was concluded that the water content of the root zone may influence the development of edema in tomatoes. Other research has pointed to light quality (lack of ultraviolet light) being a driving force behind the development of edema in Northern greenhouse tomato production. Due to largely overcast, low light conditions during winter months, most of the lighting provided to tomato crops in greenhouse operations are supplied by high pressure sodium (HPS) fixtures. While these units produce significant amounts of light in the yellow/red spectrum (550 – 650 nm), they lack in short wavelength energy (300 – 400 nm) (Figure 7). This shortwave energy is also lost in greenhouses constructed with glass glazing which has relatively low transmissivity of UV light as compared with polyethylene glazing.

In the same study by Kansas State, it was found that UVB helps prevent the formation of intumescence. In another experiment, conducted at the University of Arizona2, using small doses of end-of-day far red (EOD-FR) and a 75% blue light ratio led to a decrease of intumescence injury from 62-70% of leaves being symptomatic to only 5%. Work at Michigan State University3, found dramatically reduced edema symptoms when light with
50:50 Blue:Red ratio was used as compared with 100% Red light.

Edema of Kale

In kale, sudden increases in humidity can cause edema, often coinciding with outdoor weather like rain. Edema can be especially impactful on kale crops as the superficial appearance of leaves affects their marketability (Figures 5 and 6). Maintaining a low relatively humidity within greenhouse environments and changing management strategies to better cope with outdoor weather will help prevent edema in kale. This may include increasing shading within a greenhouse to reduce use of cooling pads to help manage humidity. Changes to irrigation timing and application or spacing plants further apart may also help to reduce humidity.

Solutions

Controlling the impact of edema should be done on a case-by-case basis for each operation and based on likely causes. As mentioned before, the severity of intumescence on tomatoes is largely dependent on the susceptibility of the cultivar and individual plants. If the crop is experiencing major leaf senescence and poor yields, it may justify the cost to invest in preventative measures. Most modern lighting fixtures with digital ballasts can run both high pressure sodium and metal halide (MH) bulbs. For older magnetic ballasts, conversion bulbs can be purchased that also allow you to utilize MH bulbs in an HPS fixture. While somewhat less efficient and shorter lived, the benefit of metal halide is it provides more of a “full-spectrum” light output, with significantly more short wavelength energy (Figures 7 and 8). This strategy combining HPS and metal halide could reduce the onset of edema-like symptoms. While a considerably costlier investment, LED fixtures offer the greatest flexibility in light quality. As prices decrease and efficiency increases, LED technology may offer the solution to improved yields through the reduction in intumescence frequency.

For many other growers, the prevalence of edema may not justify the investment of retrofitting an entire greenhouse. One preventative measure that can be taken to reduce the risk of edema is ensuring the proper environmental conditions of a greenhouse. This includes the ventilation of excessive humidity, proper use of supplemental lighting during periods of low ambient lighting, and irrigation management (to avoid saturating the root zone). It may also be beneficial to experiment with a variety of cultivars to screen for edema-like symptoms or work with a seed distributor on selecting cultivars that are less sensitive to edema. No matter the situation, it is advantageous to develop an action threshold to determine at what level of prevalence should you address the issue of edema in your operation.

Citations

¹Rudd, N. (2009). Environmental Factors Influencing the Physiological Disorders of Edema on Ivy Geranium (Pelargonium Peltatum) and Intumescences on Tomato (Solanum Lycopersicum) (Masters of Science). Kansas State University.

²Eguchi, T., Hernández, R. and Kubota, C., 2016. Far-red and blue light synergistically mitigate intumescence injury of tomato plants grown under ultraviolet-deficit light environment. HortScience, 51(6), pp.712-719.

³Wollaeger, H., & Runkle, E. (2014). Does light quality impact the development of edema? Retrieved from https://www.canr.msu.edu/news/does_light_quality_impact_the_development_of_edema

e-GROAlert
www.e-gro.org
CONTRIBUTORS
Dr. Nora Catlin, FloricultureSpecialist
Cornell Cooperative Extension, Suffolk County, nora.catlin@cornell.edu
Dr. Chris Currey, Assistant Professor of Floriculture
Iowa State University, ccurrey@iastate.edu
Dr. Ryan Dickson, Greenhouse Horticulture and
Controlled-Environment Agriculture, University of Arkansas, ryand@uark.edu
Nick Flax, Commercial Horticulture Educator
Penn State Extension, nzf123@psu.edu
Thomas Ford, Commercial Horticulture Educator, Penn State Extension, tgf2@psu.edu
Dan Gilrein, Entomology Specialist, Cornell Cooperative Extension
Suffolk County, dog1@cornell.edu
Dr. Joyce Latimer, Floriculture Extension & Research
Virginia Tech, jlatime@vt.edu
HeidiLindberg, Floriculture Extension Educator
Michigan State University, wolleage@anr.msu.edu
Dr. Roberto Lopez, Floriculture Extension & Research
Michigan State University, rglopez@msu.edu
Dr. Neil Mattson, Greenhouse Research & Extension
Cornell University, neil.mattson@cornell.edu
Dr. W. Garrett Owen, Floriculture Outreach Specialist
Michigan State University, wgowen@msu.edu
Dr. Rosa E. Raudales, Greenhouse Extension Specialist
University of Connecticut, rosa.raudales@uconn.edu
Dr. Beth Scheckelhoff, Extension Educator – GreenhouseSystems
The Ohio State University, scheckelhoff.11@osu.edu
Dr. Paul Thomas, Floriculture Extension & Research
University of Georgia, pathomas@uga.edu
Dr. Ariana Torres-Bravo, Horticulture/ Ag. Economics
PurdueUniversity, torres2@purdue.edu
Dr. Brian Whipker, Floriculture Extension & Research
NC State University, bwhipker@ncsu.edu
Dr. Jean Williams-Woodward, Ornamental Extension Plant Pathologist
University of Georgia, jwoodwar@uga.edu
Copyright ©2019
Where trade names, proprietary products, or specific equipment are listed, no discrimination is intended and no endorsement, guarantee or warranty is implied by the authors, universities or associations.

Join us on Tuesday, March 12, and explore additional tools for expanding farm revenue through vertical farming innovations.

Virginia Tech and Virginia Cooperative Extension invite you to register at http://bit.ly/Register-2019-Vertical-Farming  for the 2019 Virginia Innovation in Greenhouse and Vertical Farming Conference

Tuesday, March 12, 2019

Virginia Farm Bureau
12580 West Creek Parkway; Richmond, Virginia

Keynote Speaker
Neil Mattson, Ph.D., Cornell University

Special Guest Speaker
Chris Higgins, Hort Americas

In addition, you will hear from:

• Jerry Conner, Four Oaks Farms
• Travis Higginbothan, Fluence Bioengineering
• John McMahon, Schulyer Greens
• Ryan Pierce, Fresh Impact Farms

Join academic and industry experts in exploring the latest advances in vertical farming, greenhouse technology, sensor technology, lighting, and automation.  Hear from technical experts and Virginia producers who have been successful in incorporating controlled environment agriculture into their business models.

Register by visiting http://bit.ly/Register-2019-Vertical-Farming before Thursday, February 28.

Cornell University researchers developed a “fast crop” production schedule for greenhouse lettuce. But growers may have to alter cultural practices to avoid tipburn caused by calcium deficiency.

Tipburn is a physiological disorder of greenhouse-grown lettuce that can be a problem for growers who are trying to produce their crops in a short period of time. Tipburn can have a significant impact on the salability of a lettuce crop. The same disorder can manifest itself in tomato crops as blossom end rot.

“A challenge for greenhouse growers trying to produce their lettuce crops as fast as possible is ensuring that all of the nutrients are distributed to all the different parts of the plant in the right quantities,” said A.J. Both, associate extension specialist at Rutgers University. “In the case of lettuce, what sometimes happens is calcium cannot be transported fast enough in sufficient quantities to the quickly developing young leaf tissue. The plants’ cell walls cannot form properly and the cells collapse. This happens in the inner hearts of the lettuce heads.

“When the young leaves start to push out and grow larger these brown leaf edges appear. This is referred to as tipburn. Research showed that it is a calcium deficiency that causes tipburn.”

Both said Cornell University researchers encountered this disorder when they were developing a fast crop greenhouse production system for finishing lettuce in 35 days.

“This is a very fast crop—five weeks from seed for a 5-ounce head of lettuce,” he said. “The time between seeding and transplanting takes 11 days. The remaining 24 days the plants are in the greenhouse.

“The five-week production cycle is not the way most commercial operations grow their lettuce. Growers usually allow the growth rate to fluctuate depending on the amount of natural light the plants receive. In the summer when light levels are higher, growers can finish a crop in five to six weeks. But in the winter when natural light levels are lower, the crops take longer, as much as double the production time that occurs during the summer. If a lettuce crop can be grown at a slower rate, tipburn may not be an issue. At a slower growth rate, the nutrient uptake rate can better keep up with the plants’ demand.

“In the Cornell fast crop system supplemental lighting is used to ensure every crop finishes in five weeks. If the plants are pushed with supplemental light allowing this fast growth rate to occur, then tipburn can show up very quickly. A growing strategy was needed that allowed for a fast growth rate, but prevented tipburn from occurring.”

Both said the damage to the young leaves caused by calcium deficiency can happen within days. It may take a few more days after the damage occurs for growers to observe the symptoms.

“When the conditions for this disorder are right and there is not enough transport of calcium, the damage can start within a day,” he said. “Depending on how long the deficiency lasts will determine how severe the tipburn symptoms will be.”

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Increasing plant transpiration rates

Both said researchers and growers have found that the rate of nutrient uptake, including calcium, can be increased by stimulating plant transpiration.

“Increasing the rate of air turbulence around the leaves leads to a higher level of transpiration from the leaves,” he said. “As a result, there is a higher rate of water uptake from the roots and translocation of the nutrients, including calcium, from the roots to the developing leaves.”

Both said different methods have been tried to raise the transpiration rate in plants in order to increase calcium uptake into the leaves.

“One of the solutions mentioned in research literature is to hang a small plastic tube above each head of lettuce and blow air through it so that air is delivered onto each individual head,” he said. “This might be feasible for a small growing operation, but for a large greenhouse with thousands of heads of lettuce that would be very difficult to do.”

Working with Cornell University researchers, Both turned typical greenhouse horizontal airflow fans 90 degrees so that the air from the fans was directed downward onto the crop, resulting in an increased transpiration rate of the plants.

“We used regular horizontal airflow fans and mounted them on a different bracket so that instead of moving air horizontally, they were moving air straight down,” he said. “If the fans were placed in a uniform pattern above the crop so that most of the plants received the air flow, we saw good results in preventing tipburn.”

Both said determining how many horizontal air flow fans need to be installed to raise the plants’ transpiration rate will require some trial and error. Traditional ceiling-type fans can also be used to create sufficient vertical air flow.

“The set up works, but on occasion conditions exist that despite our best efforts to increase air flow around the plant canopy, we still saw tipburn symptoms,” he said. “We were able to prevent tipburn under most conditions, but not all the time. There really wasn’t a satisfactory explanation for why sometimes we were able to prevent tipburn and other times it occurred.

“Although we have limited scientific data to back this up, the further away from the center of the fans there would be less air flow and the air movement may not be enough to sufficiently raise the transpiration rate to overcome tipburn. But where that location is in a particular greenhouse will require some experimentation with where the fans are placed, the distance between the fans and the plant canopy and how many fans are installed.”

Both said the fan set up was trialed with lettuce crops grown in troughs and in a floating production system.

“We have used the fans with both types of production systems and they worked equally well in preventing tipburn,” he said. “In a floating system, plants often experience a variety of conditions because the plants are usually pushed through the entire system from the seedling stage to the harvesting stage. In the case of troughs, the plants are usually stationary, but there could be more air movement between the plant rows because troughs are typically elevated. In either system, there is usually more air movement around the plants when they are smaller in size. Tipburn often becomes an issue when the plants have reached a larger size.”

Maximizing growth with supplemental light

In developing the fast crop production system for lettuce, Cornell researchers used both natural and supplemental light to maximize growth. High pressure sodium lamps were used to provide supplemental light.

“We tried to achieve a daily light integral of 16-17 moles per square meter per day during the entire production cycle,” Both said. “If the 16-17 moles were reached using natural light, then the lamps wouldn’t come on. If it was cloudy and we couldn’t achieve that light level with just natural light, then the HPS lamps came on to provide supplemental light.

“If we stayed at or just below this daily light integral number and provided vertical air flow, we were able, in most cases, to prevent tipburn. If we went above this daily light integral in order to try and push the growth of the plants even further, we were able to grow the plants, but tipburn occurred in many cases even though vertical air flow was used.

“We could have grown the lettuce at a lower light level and prevented tipburn, but it would have taken longer to finish the crop. This is also an economical consideration, because at a lower light level a grower wouldn’t be able to turn as many crops and thus would make less money.”

Substituting supplemental carbon dioxide for light

Another option that was studied to keep plants growing quickly was to use less supplemental light and to increase the amount of carbon dioxide in the greenhouses by a process called carbon dioxide enrichment.

“The grower would reduce the amount of supplemental light and increase the amount of supplemental carbon dioxide,” Both said. “A grower can easily manipulate the carbon dioxide level by releasing pure carbon dioxide gas. Using this technique, a grower might provide a daily light integral of 12-13 moles per square meter per day and increase the carbon dioxide concentration to 1,000-1,200 parts per million (approximately three times the ambient concentration) and would still be able to finish a crop in five weeks.

“A grower could choose whether it would be cheaper to pay for the electricity to run the supplemental lighting system or if it would be cheaper to add supplemental carbon dioxide. In our research, there wasn’t a difference in the amount of tipburn when plants were grown at a lower light level and a higher carbon dioxide level. The vertical air flow system would still need to be used when growing at higher carbon dioxide concentrations and lower supplemental lighting levels.

“I would expect that it would be cheaper for most growers to increase the carbon dioxide concentration than it would be to increase the daily light integral using supplemental lighting. However, if a grower decided to grow the plants at 16-17 moles per square meter per day and increase the carbon dioxide concentration, the plant growth rate would increase, but tipburn would occur sooner.”

For more: A.J. Both, Rutgers University, Department of Environmental Sciences, BioEnvironmental Engineering;

(848) 932-5730; both@aesop.rutgers.edu;

For more information on the production of controlled environment agriculture hydroponic crops, including lettuce, see http://www.cornellcea.com.

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

Tuesday, August 11, 2015

What’s Trending in Horticulture?

Brought to you by Cornell University and New York State Flower Industries

Five reasons Cornell Floriculture Field Day is the must-attend event of summer:

1. New! Cornell Alumni and Friends reception. Come to Ithaca, NY an evening early for the 2015 alumni and friends event at the gorgeous Cornell Plantations visitor center. The event features appetizers, New York wine and jazz.
2. Armitage and Konjoian kickoff the morning program. Dr A will talk about some of his favorite annuals, perennials and veggies for the landscape.  Peter Konjoian will inspire you to consider making the switch to greenhouse vegetables.
3. Edibles featured in trials. New to the annual flower trial beds at Bluegrass Lane are patio vegetables, mixed flower and edibles containers, and a trial of retail potting mixes.
4. Cut flowers in high tunnels. Chris Wien presents on several years of research growing cut flowers in fields and high tunnels. Attendees can also visit the nearby cut flower high tunnel research facility.
5. Cornell Dairy ice cream. The afternoon ends with our annual ice cream social. You’ll have to show up to find out which flavors are featured this year.

Cornell’s Floriculture field day is Tuesday August 11th at the Cornell campus in Ithaca, NY. The alumni event will be held the evening prior. More information and online registration for both events is available at www.greenhouse.cornell.edu

Download the pdf flier and schedule here.

Kathy Pufahl Container Design Competition

held in conjunction with Floriculture Field Day on August 11, 2015