Using Each Season and Crop as Preparation for the Next in High Tunnel Production

Tomato production dominates main season, summertime high tunnel use but presents challenges. Like an increasing number of growers, we experiment with ways to maintain high tunnel soil productivity and profit potential for the long-term. Our operating principle is that crop and market diversity are useful and while some crops offer less income potential, their contribution to the success of the farm may not rest entirely in their specific balance sheet. Our posts on 10/28/23, 2/17/24, and 7/27/24 provide additional information and highlight some of our recent and ongoing work focused on ensuring year-round success in high tunnel production. Recent activities involving butternut squash, a mixed-species summer cover crop, and various vegetable and flower crops are summarized below.

Three panels focused on a mixed-species summer cover crop (cowpea, Italian ryegrass, pearl millet, and sorghum-sudangrass) seeded on 6/5/24 and terminated on 8/20/24.

As before, other HTs at our location are also being used to test and illustrate additional year-round production options involving crop selection and HT environmental management. Pictured is a small subset of the crops harvested or soon to be harvested since March-2024 (see https://u.osu.edu/vegnetnews/2024/02/03/a-minimalist-approach-to-ensuring-fall-through-spring-vegetable-harvests/) for a summary of crops harvested 11/23-3/24.

 

A Better High Tunnel Poly Covering?

High tunnel growers have long used standard 6 mil poly film to cover their structures. Standard 6 mil poly film is the “covering” workhorse of the high tunnel industry. However, as most high tunnel growers know, standard 6 mil poly film can be punctured easily, will continue to tear if cut, eventually becomes brittle and less transparent, retains very little heat energy, and allows sunlight to escape the high tunnel without contributing to photosynthesis, which hampers growers wanting to maximize growth fall-to-spring. Regardless, standard 6 mil poly film needs to be replaced every three to five years in many locations. While many growers may not give the film that covers their high tunnels much thought, it is usually the only thing that separates their crops from the outside and it influences their success in many obvious and not so obvious ways. Therefore, it is reasonable for growers to seek and expect improved high tunnel coverings just as they expect better versions of all other materials used on the farm.

We are pleased to be cooperating with the Seaman Corporation of Wooster, Ohio (https://www.seamancorp.com/), long known as an industry leader in high performance industrial fabrics. Together, we are evaluating the company’s exciting new experimental reinforced poly film which is far stronger and more puncture and tear resistant than standard 6 mil poly film and has other interesting properties that may, for example, allow it to supplement or replace hard polycarbonate in some applications.

As depicted below, HT 103 on the CFAES-Wooster campus currently contains a crop of butternut squash and was covered with the new film on 8/12/24. HT 204 is about 100 ft east of HT 103, identical in shape and age, covered with standard 6 mil poly film, and holding butternut squash. Going forward, cropping, ventilation, and other practices will be the same and environmental conditions will be monitored in both high tunnels. Therefore, overall, differences in environmental conditions and/or crop status in the two high tunnels are likely to result from their different coverings. Monitor temperature and relative humidity in high tunnels 103 and 204 and six other structures at the same location at https://u.osu.edu/vegprolab/resource-1/ and stay tuned for updates on this important evaluation.

A Minimalist Approach to Ensuring Fall through Spring Vegetable Harvests

Interest in marketing locally-grown, freshly-harvested vegetables fall through spring is strong and increasing among high tunnel growers in the Midwest, Great Lakes, Mid-Atlantic, Mid-South, and Northeast. Scanning the agendas of industry meetings and listening to growers and others in these areas makes clear that fall through spring harvest and marketing of high tunnel-grown crops is an established and increasingly common practice. Importantly, some growers have transitioned to cash cropping their high tunnels only fall through spring and leaving summer to grow cover crops and focus on other priorities, including field-based production. Conversations with and public presentations by these growers and other experts make clear that fall through spring income from high tunnel production can be significant if the correct crops and varieties are chosen and suitable practices are used.

We have long wondered which crops, varieties, and practices may be ideal for Ohio high tunnel growers looking to harvest fall through spring. Much of our previous research focused on a relatively small number of crops and the use of various tools and practices (e.g., films, fabrics, and/or soil heating). Our goal was to describe potential production outcomes when high tunnel growers invested in the process to various levels. Results from those experiments suggest that yields are likely to be greatest when investments are also highest, for example, when soil heating, plastic films, and row covers and the effort to maximize their utility are used. Those studies were summarized previously in this blog.

We are asking a different question in Winter 2023-2024. As the three panels below describe, seven crops were seeded in two high tunnels in October-2023 and grown without any supplemental heating, films, or row covers. This “minimalist” approach explores the worst-case scenario, the minimum that can be expected from these crops under the conditions they have experienced since seeding. This approach may appeal to growers unfamiliar with fall through spring production and/or those who are unwilling or unable to invest much time, money, or effort in it, at least at this time. The test outlined below is one example of what can be expected but many others exist. Of course, different outcomes may be possible when other varieties, planting dates, and growing practices are used. Upcoming evaluations will push the “minimalist” approach further as all crops capable of being grown and harvested fall through spring do not require a high tunnel. Please contact me (Matt Kleinhenz, 330.263.3810, kleinhenz.1@osu.edu) if you would like more information.

 

2022 Pumpkin and Squash Hybrid Trial Results

What better day to post the pumpkin and squash hybrid trial results than Halloween?

A pumpkin and squash hybrid demonstration trial was conducted at the Western Ag Research Station in South Charleston, OH. In order to have mature fruit for the late August field day, the following longer season hybrids were seeded early and transplanted on May 31: Giltedge Gold, Quigley Gold, Igor, Bannack Gold, Death Star, Tons of Fun, Sweet Baby Jane, Spartacus, Garnet Gold, Fireball, Autumn Frost and Icicle. The remaining eight hybrids were also direct seeded on May 31, bringing the total number of hybrids in the trial to 20. Hybrids in the trial included traditional orange jack-o-lantern fruit, other colorful or textured fruit, various edible ornamental squash types, and some recently released hybrids (Table 1).

The trial focuses on demonstrating host plant resistance to powdery mildew, as well as observing general plant health and vine growth. A second function of the trial is to evaluate hybrid fruit size, shape, color, etc. and to obtain some estimates of yield, average fruit weight and number of fruit per acre based on our production methods.

Each plot in the trial was 60’ long and planted on 15’ row centers (0.02A per plot). There was no replication of the plots, all data was collected from a single plot. In-row plant spacing was set at 3.5’ for all hybrids. Despite using FarMore FI400 treated seeds when possible some additional seedling losses occurred due to bacterial wilt infections. Some plants were also lost to mid-season infestations of squash vine borer. Reduced stand is noted in Table 1.

For weed control, Strategy (4pt) plus Dual (1.3pt) plus glyphosate (32oz) per acre was applied pre-emergent followed by Sandea (1oz/A) between the rows prior to the vines running. Hand hoeing and pulling on weekly basis prevented major weed escapes. Based on soil sampling no P or K was applied but ca. 75 lb N was sidedressed using 28-0-0 on June 24.

Table 1. Hybrids in trial and associated development notes. * = reduced stand, BW = bacterial wilt, BLS = bacterial leaf spot

Harvest data was collected on September 1 as the majority of plots showed 95+% mature fruit. From each plot, four representative fruit were clipped and weighed, with all other remaining mature and immature fruit counted and used to estimate yield data per acre. Please keep in mind this report only provides an estimate of yield and fruit potential based on our production methods which are likely quite different than traditional production farms. If harvest was delayed a few weeks later in the season, yield estimates would likely increase as immature fruit become mature.

Table 2. Hybrid trial yield data. * = reduced stand.

For powdery and downy mildew control, fungicides were initially applied July 25 but then re-applied on a 7-10 day schedule throughout the season following proper resistance management rotation guidelines. The last application was made on August 26. Spray applications were made at 36 GPA and 65 PSI using hollow cone nozzles.

 A group photo of all the fruit in the trial can be found in Figure 1, with a basketball and softball for size reference.

Figure 1. Group shot of 2022 pumpkin and squash fruit with basketball and softball as a size reference. On straw bales (L to R) Giltedge Gold, Lemonade, Eros, Fireball, Hermes, Garnet Gold, Spartacus. Large fruit in front of straw bales (L to R) Quigley Gold, Tons of Fun, Igor, Bannack Gold, Death Star, Sweet Baby Jane. Small fruit in front of straw bales (L to R) Autumn Frost, Autumn Pearl, Fort Knox, Winter Blush, Moon Stacker, Icicle, Warty Gnome.

If you have any questions about the trial, please feel free to contact Jim Jasinski, Jasinski.4@osu.edu.

A Simple, Inexpensive, DIY System for Controlling the Height of High Tunnel Sidewall Rollbars Remotely

The Problem

High tunnel growers come to know through trial and error and some hardship that their success depends on managing the temperature and other conditions inside the high tunnel with care. That is, that maximum yield and quality are possible only when conditions inside the tunnel and near the crop are optimal as often as possible. High tunnel growers also come to learn that achieving optimal conditions round-the-clock and day after day is difficult and costly in various ways. For example, it is difficult because crop needs and conditions outside the tunnel can change dramatically and quickly, especially during key points in the crop cycle in spring and fall. Reacting to changes in crop need and other must-dos on the farm can be challenging. Managing temperature and other conditions inside the tunnel usually also requires undesirable investments in time, effort, and money. Of course, conditions inside the tunnel are usually set by controlling the extent to which sidewalls, vents, and/or doors are open, with the height of sidewall rollbars being particularly significant. The trouble is that the position of most sidewall rollbars is set by hand. This requires the grower or another person to stop what they are doing, travel/go to the high tunnel, and reposition the rollbars manually. This commitment and expense are unfortunate enough. However, the fact that it may need to be done multiple times per day for many days in a row for conditions near the crop to remain optimal becomes problematic for many high tunnel growers. They are required to choose between: (a) continually repositioning sidewall rollbar heights (“babysitting” the tunnel) at some direct cost and at the expense of engaging in other activities or (b) setting sidewall rollbar position at a “compromise” height and accepting the consequences of conditions (e.g., temperature, wind) being above- or below-optimal for potentially lengthy periods. In our view, high tunnel growers should not be required to have to make that choice.

Existing and New Solutions

Various companies (e.g., https://www.advancingalternatives.com) agree and offer automated ventilation control systems involving sensors, a control panel, and sidewall motors. We have had a version of the Advancing Alternatives system on a moveable Rimol high tunnel since 2015 and have been very pleased with both (control system, high tunnel). The high tunnel’s sidewall motors, endwall vents, inflation fan, and control panel are all powered by a standard 12-volt battery charged by one medium-size solar panel. It’s an impressive system. However, we are also aware that fully automated approaches to ventilation can cost more than some growers are willing or able to pay and place control of the high tunnel conditions largely in the hands of the control panel, not the grower.

Therefore, we have been working to develop a low cost, DIY way to control sidewall motors remotely that keeps the grower directly in control of sidewall position (e.g., to account for conditions that a fully automated system may not monitor, at least without additional cost).

Alex Herridge will soon complete his undergraduate degree in Computer Science and Engineering at The OSU and his contributions to the effort have turned the idea for this alternative, grower-friendly system into reality. Full plans for the system will be available in a separate publication soon but its key features include:

1. Standard sidewall motors powered by a battery-solar panel combination, as described above;
2. A standard voltage-regulating unit converting 12 volts from the battery to 24 volts needed by the motors (approx. $80.00);
2. A motor controller (available at electronics stores or online for approx. $15.00);
3. An off-the-shelf, WiFi-enabled microcontroller to act as the brains of the system (approx. $5);
4. WiFi already present on the farm property or wireless access with a hotspot or similar ($0 to monthly charge typical of a mobile phone plan); and
5. Code for the motor controller (no charge).

To proceed, motors are attached to sidewall bars and powered and a basic network connection linking the grower’s phone (or other device) and the microcontroller is established. The entire process can be completed in approximately four hours once all materials and WiFi are on site. Thereafter, the sidewall motors can be controlled with one’s mobile phone or other linked device using a simple interface setup for the purpose. Pictures of the preliminary, bare-bones version of the interface we used to raise and lower a sidewall bar on a high tunnel at OARDC on December 13 are given here. The bottom-line of this approach and system is that it will allow growers to raise and lower sidewalls from wherever they have internet access using low cost, off-the-shelf hardware. Watch for additional posts regarding this system at VegNet and other locations and contact me (Matt Kleinhenz; kleinhenz.1@osu.edu; 330.263.3810) if you are interested in learning more about or testing the system on your farm.

(OSU Computer Science and Engineering student with the motor and micro controllers and standard battery charged by a solar panel.)

(Exterior of the Rimol moveable high tunnel and the solar panel used to charge the battery powering rollbar motors, endwall vents, inflation fan, and control panel.)

(Simple, password-protected interface for controlling sidewall rollbar position. Usable from anywhere the owner has internet access and allowing them to control sidewall rollbar height remotely.)

 

 

 

 

 

Insect Pest Management in Vegetable Crops Survey

Dear vegetable producer,

You are being asked to participate in a study, “Insect Pest Management in Vegetable Crops Survey” (Purdue IRB protocol no. 2021-979) by researchers at Purdue University and The College of Wooster. The purpose of this study is to get more information on insect pest management practices and strategies used by vegetable producers in the Great Lakes and Mid-Atlantic regions. The information provided here will help direct pest management research and extension programs in specialty crop production.

You must be at least 18 years of age to participate. The survey will take approximately 20-25 minutes to complete. The survey is anonymous. The researchers have pledged to keep your data confidential and will only report aggregated results in any published scientific study.

In appreciation of your choice to participate in the survey, you can choose to enter into a raffle for a hardcopy of one of two complimentary spray guides: the Midwest Vegetable Production Guide for Commercial Growers ($21 value), or the Mid-Atlantic Commercial Vegetable Production Guide ($25 value). Instructions for entering the raffle can be found at the end of the survey.

To begin the online survey, click this link.

Participation in this study is voluntary and you may withdraw from participation at any time. If you have any questions, you may contact the researchers:

Dr. Carlo Moreno (First point of contact)
The College of Wooster
931 College Mall, Wooster, OH, 44691
Phone: 330-287-1982
Email: cmoreno@wooster.edu

Dr. Elizabeth Long
Purdue University
901 W. State Street, Lafayette, IN 47907
Phone: 765-496-1918
Email: long132@purdue.edu

Bt Sweet Corn Trial Update

Two Bt sweet corn trials were conducted in South Charleston and Wooster in 2021 to determine the efficacy of various Bt gene traits against common lepidoptera (moth) pests such as corn earworm, European corn borer and fall armyworm. Both trials were planted in late June and harvested for evaluation in early September to maximize caterpillar damage. No insecticide treatments were applied to any of the treatments.

Corn earworm filled trap near sweet corn trial.

The South Charleston trial contained two non-Bt hybrids (Providence & Obsession I) and two Bt hybrids (BC0805 & Remedy). There was a fifth hybrid in the trial (Bt traited Obsession II) but it was destroyed by a misapplication of herbicide. In Wooster only Providence (Non-Bt) and Remedy (Bt) were planted.

The primary pest of concern for late planted sweet corn is the corn earworm. There were heavy flights around silking in South Charleston but lighter flights around silking in Wooster. In South Charleston, 98% of Obsession I ears (non-Bt) were damaged, 100% of Providence ears (non-Bt) were damaged, 91% of BC0805 ears (Bt) were damaged but only 0.7% of Remedy ears (Bt) were damaged. In Wooster, 86% of Providence ears (non-Bt) were damaged and 1% of Remedy ears (Bt) were damaged.

Corn earworm caterpillar in ear tip.

It is reasonable to assume that corn earworm would readily damage non-Bt sweet corn ears that were not protected by any insecticide, but why weren’t both Bt sweet corn hybrids (BC0805 and Remedy) protected from damage? The answer lies in the actual Bt traits each hybrid contains; BC0805 is an Attribute I series containing only Cry1Ab genes while Remedy is an Attribute II series hybrid containing Vip3A + Cry1Ab Bt genes. There is general consensus that Cry1Ab Bt genes alone are not protective in sweet corn against lepidoptera pests.

Sweet corn hybrid evaluation underway.

This was the first time any damage had been recorded on Remedy sweet corn in OSU trials. This is important to note because it is a signal that resistance against Vip may be evolving in the CEW population. ECB was not detected in the South Charleston trial and only found in one ear in the Wooster trial. No FAW was found in either trial. Regardless of location within the state, for late planted sweet corn, all hybrids not containing the Vip Bt protein (Remedy/Attribute II) will need to be protected with insecticide sprays to yield relatively worm free ears. Even Vip Bt hybrids may gain some protection from other pests such as stink bugs by adding insecticide sprays.

 

2021 Pumpkin and Squash Hybrid Trial Data

A hybrid pumpkin and squash hybrid trial was planted in the Western Ag Research Station in South Charleston, OH. There were 29 hybrids evaluated in the trial ranging from traditional jack-o-lantern fruit to more colorful or textured fruit from a variety of companies as seen in this group photo (Figure 1). The trial focuses on demonstrating foliage tolerance to powdery mildew as well as observing general plant health and growth patterns. A second function of the trial is to evaluate hybrid fruit size, shape, color, etc. and to obtain some estimates of yield and fruit numbers per acre based on our production methods. As these methods are likely to change from grower to grower, so will expected yields and fruit numbers. This report is only to provide an estimate of yield and fruit potential.

Figure 1. Group shot of pumpkin and squash fruit in 2021 trial.

Each plot in the trial was 50’ long and planted on 15’ row centers. There was no replication of the plots, so all data was collected from one plot. The trial was direct seeded on June 1 but nine hybrids were transplanted on May 27 due generally to later maturities so that all fruit would be mature by the pumpkin field day on August 26, which was successfully accomplished. In-row plant spacing was set at 3.5’ for all hybrids.

Harvest and fruit number data were collected on September 2 as all plots showed 95+% mature fruit. Three to five representative fruit were clipped and weighed from each plot, with all other remaining mature and immature fruit in each plot counted. Estimations of yield and fruit numbers for each hybrid are based off of 50’ row plots (0.017A) extrapolated out to a full acre.

For weed control, Strategy (4pt) plus Dual (1.3pt) plus glyphosate (32oz) per acre was applied pre-emergent followed by Sandea (1oz/A) between the rows prior to the vines running. Based on soil sampling no P or K was applied but ca. 75 lb N was sidedressed on using 28-0-0 on June 15.

For powdery and downy mildew control we began applying fungicides July 22 on a 7-14 day schedule following proper rotation guidelines, with the last application being made on August 30. Spray applications were made at 36 GPA at a pressure of 65 PSI using hollow cone nozzles.

Below are listed the basic information and some general notes about each hybrid in the trial listed alphabetically (Table 1). All yield and fruit number data are in Table 2, listed alphabetically by hybrid name.

Table 1. Basic information about hybrid entries including seasonal notes.

 

Table 2. Estimated yield and fruit count data for 2021 trial.

If you have any questions about the trial, please feel free to contact Jim Jasinski, Jasinski.4@osu.edu.

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.