Optimizing Film, Fabric, and Root Zone Heating Combinations in Fall-to-Spring High Tunnel Vegetable Production

An increasing number of growers look to harvest and market vegetables grown in high tunnels fall to spring. Selling freshly harvested material (e.g., leafy, root, and other crops) from roughly October through April appeals to some farmers but it also raises many production-related questions in practice. Many of these questions relate to the use of plastic films, fabric row covers, and supplemental heating (including of the root zone). Questions such as which ones to use, when, for how long, under what conditions, and in what combination are common. The Vegetable Production Systems Lab has completed research in this area for more than fifteen years, cooperating with farmers often and using high tunnels at OARDC in Wooster which range in size, approach (conventional, organic; flat ground, raised beds), and other characteristics. Findings from these experiments have been summarized in publications (including VegNet) and during programs around the Eastern U.S. Our newest experiment was initiated on Sept 23 and includes the 20 wood-framed raised beds shown here, each seeded to either Scarlet Nantes carrot, Outredgeous lettuce, or Ovation greens (Brassica) mix from Johnnys Selected Seeds. This experiment will examine the influence of daily (8 am – 5 pm) root zone heating (accomplished with electric cables placed approx. 7 inches below the soil surface) in combination with vented plastic film row cover on crop development, yield, and quality. Vented plastic film covers all twenty plots (beds) while daily root zone heating occurs in ten of the twenty plots. Root zone heating will be discontinued at six weeks after seeding but the film will remain in place through final harvest in December. These treatments were chosen partly because two findings have been common in previous research. First, crops (e.g., lettuce, Brassica greens, carrot) and varieties have responded very differently to the use of film, fabric, and root zone heating — whether used alone or in various combinations. The same trend appears to be underway given the relative sizes of the crops shown in the pictures below (taken 10/9/21; carrot at top, Ovation Brassica mix in middle, lettuce at bottom). Second, in this experiment, we are very interested in root zone heating as a supplement to the above-ground heating that occurs with film in place and is typically pronounced September to early November and late January through March. Finally, temperature and relative humidity are recorded in each plot every five minutes, allowing us to describe treatment effects on these conditions very reliably. The sensor unit shown in the bottom-most picture below also relays the temperature and relative humidity readings to the “cloud,” allowing us to see the numbers in near real-time. This battery- and solar-powered Hobolink monitoring and reporting system from Onset Computer Corporation has been in place for more than two years and has greatly enhanced the efficiency and effectiveness of our high tunnel ventilation management across the ten tunnels in our program.

 

IR-4 Survey for Specialty Crop Growers

Attention Specialty Crop Growers!

IR-4 (https://www.ir4project.org/) is conducting their biannual Specialty Crop Growers & Extension survey to assess what disease, pest, and weed problems growers have a difficult time managing because they do not have sufficient management tools.

If you aren’t familiar with IR-4, we have included a link to their website above to learn more.

The deadline to complete the survey has been extended to September 1, 2021.

If you are a specialty crop grower or an Extension Educator working with growers, please take the time to complete the survey to provide your insight and experiences. You can find the link at: https://www.ir4project.org/ehc/ehc-registration-support-research/env-hort-grower-needs-2/

Grafted Watermelon Plants: Under What Conditions and Practices Does Using Them Offer the Best Return on Investment?

A lot of research is focused on answering that two-part question for watermelon and other crops (e.g., cucumber, cantaloupe, tomato, pepper). Full answers will emerge as growers and researchers share and integrate their experiences then evolve as circumstances change. Currently, most agree that using grafted plants is most beneficial when a resistant rootstock is selected to help offset the effects of a significant soilborne disease (e.g., Fusarium, Verticillium), regardless of crop. However, rootstocks with additional traits are being tested under other troublesome conditions (e.g., salinity, heat, cold, drought, flood). Growers are encouraged to listen as peers and research-extension and industry personnel share new information on the performance of grafted plants under various conditions. Information will be specific to crop, setting (field, high tunnel), system (conventional, organic), market, farm size, and other key variables.

Soil and other production conditions are not the only factors that influence the value of grafted plants to growers. Practices used to grow the plants are also important. Plant and row spacings (plant populations), irrigation and fertility programs, and planting and harvesting dates may also affect growers’ experiences with grafted plants.

Industry-research/extension partnerships can help fast-track arriving at answers to where and how grafted plants should be grown for growers to benefit most. We work with plots at OSU and on farms to understand the impacts of in-row spacing, fertility programs, and more on watermelon fruit yield and quality. Grafted and standard (ungrafted) plants are included in each experiment. Results from a multi-year study in Wooster through 2020 are summarized in a short video at https://go.osu.edu/vegeprosystemslab. Overall, fruit number and total weight have been significantly greater in grafted plots and at an in-row spacing of five versus four feet (between-row spacing of six feet in all cases). The results suggest growers can reduce plant populations but increase yield meaningfully – i.e., reduce plant costs while increasing income potential. Importantly, evidence of Fusarium in this experiment has been absent or minimal in all previous years. As explained and shown in the panels below, Fusarium is affecting the experiment significantly in 2021. Standard (ungrafted) Fascination and Sweet Dawn plants are very weak or dead while grafted versions of both (Carnivor, Pelops as rootstocks) remain healthy and vigorous. Harvest will begin soon and fruit yield data will be available by season’s end. Please contact me if you would like more information on this experiment or grafting.

Notes from the Pumpkin Patch

Pumpkin Field Day – August 26

Pumpkin field day flyer

We are less than 13 days away from the 2021 in-person pumpkin field day on August 26 at the Western Ag Research Station (7721 S. Charleston Pike, S. Charleston). We will have two hours of presentations plus time for growers to roam the plots and see what interests them, including the powdery mildew fungicide trial, pumpkin and squash hybrid trial, and weed control plots.

The field day starts promptly at 5:30 PM where we will have Dr. Aaron Wilson from OSU talking about weather impacts on pumpkin production and Tony Dobbels reviewing a weed screen plot with 10 herbicide treatment combinations of Reflex, Sandea, Dual Magnum and Strategy. For diseases, we were very fortunate to pry Dr. Dan Egel from Purdue University to speak about disease control in pumpkins. Jim Jasinski will briefly cover the pumpkin and squash trial and powdery mildew fungicide trial. After the presentations the participants will be allowed to move around the plots. The field day will end at 7:30 PM.

Pre-registration is a must for this event so please use this link.
https://osu.az1.qualtrics.com/jfe/form/SV_7WnQLmG3bcyQWc6

Cut-off for pre-registration will be Aug. 24. No walk in registration will be possible. Social distancing and mask wearing might be required for the outdoor event so come prepared. No beverages will be provided so bring your own.

Weed Control Video on IPM YouTube

Tony Dobbels talks about weed control in pumpkins and squash

For growers who are unsatisfied with their early and mid-season weed control in pumpkin and squash,  take 15 minutes and check out this new pre-emergent herbicide video narrated by Tony Dobbels, Department of Horticulture and Crop Science. In the video, Tony reviews 10 herbicide treatments and combinations of  Sandea, Dual Magnum, Strategy and Reflex (currently under a 24c label) and gives his thoughts on their level of control and fit for overall pumpkin and squash production. Watch the video here: https://youtu.be/NmSX4FqK7T4

Powdery Mildew Beginning to Roll
After what seemed like a slower than average start to the powdery mildew season (at least at the research station), leaves in the untreated checks have been climbing to between 50-75% coverage. Be sure to treat on a 7-10 days schedule and use proper FRAC number rotation to reduce the incidence of fungicide insensitivity. Sally Miller’s article on July 10 (https://u.osu.edu/vegnetnews/2021/07/10/addendum-more-powdery-mildew-fungicides-for-cucurbits/) is a great resource to what has been working lately in Ohio and is a must read as we approach the mid point of the disease management season.

Pumpkin Insects Report
For the most part squash vine borer has died down for the season. I saw some extensive damage in the Hardin County crop walk a few weeks back in zucchini but haven’t seen it in any of my pumpkin or squash plantings at the station, although I have been actively catching adults until about two weeks ago.

Cucumber beetles are still hanging out in the flowers but as we approach 100% orange in some of our trials, fewer and fewer flowers are being produced so I expect a switch soon to possible rind feeding. If you are in a similar situation, keep an eye on flower production and where the beetles are actively feeding to avoid rind damage which could lower market quality.

Mating squash bugs.

So that leaves squash bugs as the only insect I see at the station beginning to increase fairly steadily, with many egg masses being detected on leaves, followed by gray nymphs typically aggregated together and eventually larger brown adults. These pests have sucking mouth parts and can feed extensively on the petioles, vines and fruit, sometimes causing collapse. If there are over one egg mass per planting, treatment of the emerged nymphs is easier than waiting for them to become adults. Only treat if necessary to avoid aphid explosions with their accompanying honey dew and black sooty mold on leaves and fruit.

Partnerships, Teamwork, and Persistence Bring New Potato Varieties

Hundreds of new, promising, numbered (unnamed) potato genotypes are evaluated at research station and farm sites each year. Ohio State is one of many institutions involved. In 2021, we are evaluating more than 100 numbered selections from four breeding programs against seven standard industry varieties. The same evaluation techniques we use can be employed by individual vegetable farms.

High-performing varieties are just one of the core raw materials for vegetable production, which also relies on water, mined or manufactured inputs and equipment, and the know-how to use all of them. Whether formal or informal, variety evaluation is essential for individual growers and the vegetable industry. Since now is when differences among varieties of individual crops begin to show themselves on farms and research stations, it’s a good time to discuss traits and processes used to evaluate varieties.

When we evaluate genotypes of potato being considered for naming and release as varieties, we score plant maturity and record total and marketable yield and more than ten tuber characteristics for each entry (e.g., tuber size and shape, skin color and texture, flesh color, eye depth, incidence of internal defects, and specific gravity and chip color). Collaborators in other states evaluate the same genotypes for pest and disease resistance, crop tolerance to heat stress, storage effects on tuber quality, and tuber cooking quality and sensory properties. So, like for other vegetables, developing potato varieties requires teamwork.

Background on the Variety Development Process

Experimental genotypes originate in public-sector breeding programs based at universities and the USDA. In fact, although varieties developed by private companies (e.g., major processors) contribute significantly, the U.S. potato industry (especially the fresh/tablestock and chip sectors) has long relied on varieties developed in the public sector. Public-sector varieties are developed by large teams led by universities, USDA, and/or state industry associations or organizations and account for most of the available varieties, acreage, and value of production.

Whether public or private, variety development teams include breeders/geneticists, agronomists/horticulturalists, plant pathologists, entomologists, food scientists, farmers, processors, and people with expertise in related areas.

Potato varieties are named, released, and made available for commercial use only after years of comprehensive, widespread testing, beginning with just a few plants and concluding at farm scale. Once released, varieties support processing (i.e., chip, fry), fresh market/tablestock, and/or breeding programs. The varieties ‘Atlantic’ (released in 1976), ‘Dark Red Norland’ (1957), ‘Katahdin’ (1932), ‘Kennebec’ (1948), ‘Red LaSoda’ (1953), ‘Superior’ (1962), and ‘Yukon Gold’ (1981) are just a few examples of public-sector varieties that have been planted to many thousands of acres over decades of production. Varieties like these set the bar for and/or are found in the “family trees” of newer, increasingly popular varieties.

Still, markets, production conditions, and industry factors change continuously. Therefore, variety development must be ongoing and once-popular varieties are eventually displaced by new, more farmer-, processor-, and consumer-friendly ones. The process is designed to enhance industry success and consumer satisfaction.

Evaluation is nearly continuous since sites are located throughout the U.S. and the process begins before planting and ends long after harvest. Groups based in the East, Midwest/Upper Midwest, West and Pacific Northwest, and South often coordinate the work. Ohio State and Ohio farmers and processors have participated annually for more than fifty years. We emphasize the evaluation of genotypes originating in eight breeding programs and with potential value in fresh and chip markets and have contributed to the release of multiple varieties used in Ohio and elsewhere.

Sharing Results

Data from our 2021 trials will be summarized in a report available at https://u.osu.edu/vegprolab/technical-reports/ with data from 2020 and previous years available at https://neproject.medius.re/trials/potato/ne1731 and https://neproject.medius.re/. Later, we will join team members from Maine, New York, Pennsylvania, North Carolina, Virginia, Florida, and USDA and industry partners to discuss evaluation outcomes and begin selecting new entries and others to be evaluated again or dropped from the program. With information reflecting variety or experimental selection performance in the field and on the plate, the breeder and team have key information when making the thumb-up/thumb-down decision on each entry.

Still, for all crops, the performance of each variety (or experimental genotype) hinges on how it is managed, the know-how allowing growers to get the most from each variety. Planting and harvest dates, plant populations (spacings), irrigation and fertility programs, etc. influence variety performance and, therefore, whether a grower will select the variety again. So far, potato genotype evaluations at Ohio State have been completed without irrigation and this approach has clearly affected tuber yield and quality. We are rethinking this approach and look forward to speaking with vegetable and potato growers about their use of irrigation.

What are You and Others You Hear from Willing to Pay for New Farming Technology?

Technology surrounds us and is often defined as: “the application of scientific knowledge for practical purposes, especially in industry” and “machinery and equipment developed from the application of scientific knowledge.” Whether by definition or experience, it’s clear that vegetable production requires a lot of technology. Hybrid varieties and clean lots of true-to-type seed, seed coatings and treatments, the many crop inputs (e.g., fertilizers, protectants), small and large pieces of machinery and equipment … the list is long and growing. Each technology growers rely on has its own characteristics and pros and cons of use. Therefore, it’s important to be clear on what you are willing to pay for a technology and what others (e.g., advisors, educators) say about it. Helping develop and people to use new technology effectively is a big part of my job. In recent years, I have tested and advised people on high tunnel, grafting, microbe-containing crop biostimulant, and other technologies. So, what growers like and dislike about these and other technologies and are willing to pay for them is important to me, too. Growers and others provide key information, sometimes in scientific reports. A report describing peoples’ perspectives on biodegradable mulch (BDM) caught my attention recently. It is useful in two ways. First, it includes important information on BDM, an emerging technology. Second, it can help guide similar evaluations of other technologies and, perhaps, products.

The report was published by a team of investigators led by Kuan-Ju Chen (University of Guam) and including partners at Washington State University, Colorado State University, and Massey University (New Zealand). The report is available at https://doi.org/10.21273/HORTTECH04518-20 or from Dr. Chen or me by request.

The team’s specific objective was to assess peoples’ willingness to pay (WTP) for BDM characteristics. More broadly, they wanted to understand how ‘green’ technologies affect agricultural production when they are introduced into the market. Using input from farmers, educators, advisors, and others, the team assessed the WTP for adopting BDMs and peoples’ rankings of the relative importance of different BDM characteristics. The input indicated that study participants were willing to pay a statistically significant premium for healthy soil and a lower fraction of plastic residue left in the field after harvest. The data also indicated that farmers and others ranked the attributes of BDMs differently. In this case, attributes included cost, soil health, plastic residue, and consumer premium.

People interested in BDM may wish to examine the report closely or contact me, the authors, or BDM experts about it. People considering investments in a technology (new or old) or advising people on one may wish to review the report as an example of how willingness to pay assessments are completed.

How Do You Maintain the Health – Quality – Productivity of Soils in Your High Tunnel(s)?

Growers are increasingly impacted by and/or interested in learning how to prevent declines in the health, quality, or productivity of soils in their high tunnels. More are experiencing or aware that various biotic and abiotic issues threaten crop yield and quality and farm income. As some have learned, increases in nematode populations, disease inoculum, salinity, nutrient deficiencies/excesses/imbalances, and/or compaction or reductions in soil structure can be troublesome. Thankfully, a comprehensive effort is underway to help understand and address soil health/productivity-related challenges in high tunnel production. Sponsored by the USDA Specialty Crops Research Initiative and coordinated by Dr. Krista Jacobsen of the University of Kentucky, researchers with different expertise and extension specialists are documenting grower concerns and practices and charting a path leading to greater grower success. The OSU and five other universities are also currently involved. Team members recently hosted a focus group of eight growers from the Great Lakes (including Ohio) and will hear from more in other regions soon. Growers in the recent focus group represented a range of experience, size of operation, crops grown, typical number of annual production seasons (1-4), and overall farming approach (conventional, organic). Collectively, they shared concerns with issues referenced earlier and gave special attention to others such as the effects of high tunnel soils going extremely dry fall-to-spring unless watered (with or without also being cropped). Interestingly, this observation and concern lines up with the view shared by Dr. Bruce Hoskins of the University of Maine that high tunnel production is like “irrigated desert production in the west and southwest,” and that “failing to realize or take steps to address potential problems because of this” can be detrimental (see VegNet article Feb. 20, 2021). In any case, the recent conversation with growers was a reminder of: (1) potential causes of declines in (high tunnel) soil productivity (examples are listed below), (2) innovative steps growers and researchers are taking to limit the problem, and (3) benefits of addressing the complex problem through partnerships. It also prompted me to ask myself what I am doing to maintain the productivity of soils in my high tunnels. Maybe it will do the same for you!

The health-quality-productivity of soils used in vegetable production, including in high tunnels, can decline for many reasons. Some major ones are listed below in no particular order.

1. Repeated or excessive use of a potentially narrow range of fertilizers, various chemicals, and other soil amendments.
2. Vegetable plants often having relatively small and shallow root systems (compared to other annual crops) and crops returning relatively little residue to the soil.
3. Short rotations with few crops.
4. Placing frequent pressure on and aggressively disturbing soil, especially when it is wet.
5. In high tunnels, relatively unique and potentially extreme temperature and moisture profiles.

Grower Survey to Assess Herbicide Drift Damage in the North Central U.S.

 

Midwest specialty crop growers are encouraged to participate in the current herbicide drift damage survey. The study seeks to document the frequency, severity, management, and economic impact of drift damage among specialty crop growers in the North Central U.S. Even if you have not experienced drift damage, your input will be helpful in determining risk factors.

If you haven’t already done so, please take the time right now to complete this survey at go.osu.edu/driftsurvey21

The survey should take 5-20 minutes depending on your personal experience with herbicide drift. Results will help document needs for related research, education, or policy review around herbicide drift and drift management.

For more information on the study and resources on managing drift risk, please visit go.osu.edu/ipm-drift.

 

Limiting Bird Damage in Sweet Corn

Bird damage in sweet corn and other specialty crop production can be significant and those affected by it need different types of effective solutions. Some are described in articles and publications such as https://vegetablegrowersnews.com/article/some-tips-to-curb-bird-damage-in-specialty-crops/, https://ag.umass.edu/vegetable/fact-sheets/preventing-bird-damage, and https://rvpadmin.cce.cornell.edu/uploads/doc_691.pdf. Still, the search for additional farm-ready ‘tools in the toolbox’ continues. A team led by the University of Rhode Island is working with growers in the Northeast and other regions to better understand the extent of the problem and success of current control measures. Consider completing their very brief (5-minute) survey at https://uri.co1.qualtrics.com/jfe/form/SV_8qBBeU2HAIwcKYl to help inform and get the most from the team’s work.

 

Grower Survey to Assess Herbicide Drift Damage in the North Central U.S.

A special project group of the North Central Integrated Pest Management (IPM) Center wants to learn about your concerns and experiences with herbicide drift. The group is surveying growers of fruits, vegetables, and other specialty crops in the upper Midwest.

To truly understand the frequency, severity, and economic impact of herbicide drift on specialty crops, we need to hear from growers: growers who have experienced drift damage, growers who can share their concerns around this issue, and even growers who have not dealt with drift but who grow sensitive crops in drift-prone regions. Survey responses are needed to establish herbicide drift as a serious economic and regulatory concern in Ohio and across our region.

Please complete the survey at go.osu.edu/drift21.

Who should take this survey?
The study is for commercial growers of fruits, vegetables, and other specialty crops in IA, IL, IN, KS, MI, MN, MO, ND, NE, OH, SD, or WI. Even if you have never experienced herbicide damage, we would still like to hear from you if you grow specialty crops in one of these states.

Why is this survey necessary?
Dicamba and 2,4-D drift damage has made headlines in recent years, but no study to-date has attempted to quantify the overall impact drift has on the specialty crop industry. While all states have a way for growers to file a drift complaint, the process and requirements are inconsistent and may involve time and information that a grower does not have. In most states, for instance, the source of the drift must be identified. Research has found that dicamba and 2,4-D both have the potential to travel for miles in specific weather conditions, making source identification difficult.

What good will this survey do?
This study is designed to assess the potential and actual frequency of drift damage, along with the severity and economic impact of such damage. The survey includes questions on grower awareness, experience, actions, and decisions related to herbicide drift and drift-risk management. The responses will help establish needs for research on drift mechanisms, prevention, and remediation; and/or the need to review current policy and reporting requirements.

How long will it take?
The survey takes 5-20 minutes to complete, depending on your experience with drift damage.

How will this data be shared?
Summarized survey data will be shared broadly with regulatory agencies, university educators and researchers, agricultural policy makers, grower support organizations, and the general public using news articles, report summaries, and peer-reviewed journal articles. While this study is administered by The Ohio State University, it was planned in partnership with industry experts across the region who will assist with sharing results. Participants may also request a copy of the study summary.

How will my data be used and protected?
Your privacy is important. No individual survey data will be released or shared beyond the limited group of project staff. The survey questions and procedures have been reviewed by the institutional review board at The Ohio State University and are designed to protect your data and identity. Additional details on privacy and confidentiality are provided at the beginning of the survey.

How can I learn more?
The North Central IPM Center’s special project group created a series of fact sheets on herbicide drift especially for specialty crop growers. The series includes: Overview of Dicamba and 2,4-D Drift Issues, Frequently Asked Questions, Preparing for Drift Damage, and Responding to Drift Damage. Fact sheets and more information about our special project group and study are available at go.osu.edu/ipm-drift.

This study is facilitated by The Ohio State University and is funded by the USDA National Institute of Food and Agriculture through agreement 2018-70006-28884.This study is being conducted in cooperation with regional universities and non-profit grower organizations, including Ohio State Extension.