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.

 

Phytophthora Blight on Pumpkin Fruits

Phytophthora blight on pumpkins received in October 2021 by the OSU Plant Disease Diagnostic Lab in Wooster. Photo by Francesca Rotondo.

This has been a rainy growing season in much of Ohio and other states east of the Mississippi River. With intense rain events leading to standing water in fields and stretches of hot weather, both favorable for Phytophthora capsici, the cause of Phytophthora blight, the disease has been such a problem that shortages of jack-o-lantern as well as pie pumpkins are expected this Fall.  If Phytophthora blight was detected in a field at any time this season, growers are advised to harvest mature, uninfected fruits as early as possible.  These fruits need to be laid out individually (not touching, so bins are not acceptable) in a shaded area with good ventilation so that they can cure.  A barn floor would be an ideal location since they would not get rained on, but outside under a tree (to prevent sunscald) would be better than nothing.  If putting them outside, do NOT put them on a tarp or plastic that would tend to hold rainwater and spread the disease to the other fruits.  If any of these fruits start to show signs of infection (discolored areas or white, cottony growth – see photo) remove them from the area immediately and discard them in an area away from the fields or curing location.

Dr. Meg McGrath of Cornell University found that hosing pumpkins off first to remove soil (using a garden hose with a trigger spray nozzle) was the second most important step in reducing disease incidence (getting them out of the field being the most important).  Washed fruits need to be dried as quickly as possible. Dipping fruit in 10% Clorox, GreenShield or Kocide was no better than just hosing them off, and these products are not labeled for this use.

Pumpkins (or other cucurbits) with symptoms in the field should be removed and destroyed away from the field and surface water sources. Leaving them in the field will contribute to inoculum buildup; if Phytophthora blight was present in a field, practice rotation of at least four years away from susceptible crops including all cucurbits, peppers, tomatoes, and beans.

Ron Becker contributed to an earlier version of this post in 2007. We thank the Ohio Produce Growers and Marketers Association’s Ohio Vegetable and Small Fruit Research and Development Program for financial support of our disease diagnostics program.

 

 

Grow Your Own Fresh Veggies Over Winter

I like to say that Ohio is a four season growing environment.  I grow and harvest every month of the year including January and February.  I recently did a class on Growing Over Winter and many asked if I had a recording of that to view.  You are in luck.  Check out the Growing Over Winter webinar below.

There is still plenty of time to get seeds in the ground so that you can enjoy some fresh veggies all year long.

Join Farm Office Live from OSU’s Farm Science Review on September 23

Farm Science Review is back!  OSU’s Farm Office Team will be there, and we’ll broadcast the next Farm Office Live from our farm office at the Review.  We can’t promise we’ll be able to ignore biscuits and gravy, pork tenderloins, Bahama mamas, or milkshakes during Farm Office Live, but we can promise you updates on recent developments in the world of farm management and agricultural law. 

The broadcast will be on Thursday, September 23 beginning at 10 a.m.  Here’s what’s on the agenda:

  • Carbon market programs and carbon agreements
  •  Legislative update
  • 2022 crop budgets
  • 2020 Farm Business Analysis program results from crop farms
  • Ohio cash rental rates
  • Dairy Market Volatility Assistance Program
  • Highlights of FSR and upcoming programs

Who’s on the Farm Office Live Team? OSU experts are ready to help farmers, landowners and agribusiness professionals navigate the issues we all deal with in the farm office.  Our team includes:

  • Peggy Kirk Hall – Agricultural Law
  • David Marrison – Farm Management
  • Dianne Shoemaker – Farm Business Analysis and Dairy Production
  • Barry Ward – Farm Management and Tax
To learn more and register for Farm Office Live, visit https://farmoffice.osu.edu/farmofficelive.  Recordings of our previous Farm Office Live webinars are also available at that site.

Kitchen Table Conversations 2021

Grab a cup of your favorite beverage, lunch, or snack and join us from your “kitchen table” to engage in conversations “virtually” on September 21, 22, and 23, 2021 for “Kitchen Table Conversations” hosted by the Ohio Women in Agriculture of Ohio State University Extension. Conversations and discussions on “hot topics” in the agricultural world related to health, marketing, finance, legal, and production for women in agriculture.

These sessions are offered during the Farm Science Review daily from 11:00 AM-12:00 PM via ZOOM. Registration is required to participate.

Register @ https://go.osu.edu/kitchentableconversations2021

Flyer

CONVERSATION TOPICS…

9|21 Raising Livestock on Five Acres or Less

So you have some land and you want some extra income or a supply of food for your family.  This session will investigate all of your options and possibilities.

Sandy Smith, Extension Educator, Agriculture and Natural Resources, Carrol County

9|22 Farm Stress and Mental Health

It can be hard to have a conversation about our mental health, but it is just as important as acknowledging our physical health. When we live where we work stress can sometimes get the better of us. Sitting together as a family around the kitchen table fosters an environment to have tough conversations. During this session, we will have a conversation about the importance of addressing mental health concerns, how to bridge the difficult topics, and the resources that are available to you and your family.

Bridget Britton MSW, LSW….Behavioral Health Field Specialist ANR

 

9\23 On-Farm Research Opportunities

On-farm research can provide valuable local data to inform decision-making and help you understand the ROI of practices and technologies on your farm. The OSU eFields program fosters partnerships between Ohio farmers, industry, and OSU researchers. Learn about recent research trials conducted across the state and how to become involved in the program.

Elizabeth Hawkins, Ph.D…Field Specialist, Agronomic Systems, Assistant Professor

Sunshine on my pumpkins makes me unhappy

Sunburned pumpkins by handle. Note even handle is burned on one side.

This title should seem familiar as a slight twist on the famous John Denver tune from 1971. With temperatures in the low to mid 90’s for at least three days last week across most of the state, fruit that were not properly covered in the canopy were placed at a higher risk for getting sunburned.

Downy mildew infested field with no leaf canopy.

Based on observations over several years, fruit that are cut off the vine tend to burn more readily than those that remain on the vine, likely a function of being able to evapotranpirate enough moisture to stave off burning. As clade 2 downy mildew was reported on August 13 (active on pumpkin/squash), fields that were not protected suffered almost 100% defoliation with 10-14 days. Amazingly this photo with near total canopy loss had nearly no detectable sun burned fruit despite several fruit actually being desiccated to the point where they were shriveling in the sun! If these fruit were cut off the vine, I would have expected significant rind burning to occur.

While there are a few “white washing” products on the market to spray on fruit in the field to prevent burning, they have not been investigated at OSU. The best prevention is a good canopy through harvest. The next best strategies though more labor intensive would be to cut and move fruit to a shaded location to cure naturally. If fruit are in a u-pick patch, moving them to distinct piles and covering with shade cloth may also be a possible solution.

Brown Marmorated Stink Bug populations still building

Another pest that we are actively monitoring using clear sticky traps and pheromone lures is the Brown Marmorated Stink Bug. This stink bug is known to feed on vegetables, grain crops, small fruit and tree fruit.

BMSB adults on sticky trap

While we are actively monitoring for this pest in eight counties, Adams, Athens, Greene, Seneca and Wayne counties are seeing trap catch increases, mostly related to adults. Late stage nymphs and adults pose the biggest threat to tree crops like apples, with their damage resembling several other types of injury such as hail injury or bitter pit (stink bug surface injury (L), internal injury (R); Celeste Welty).

Stink bug injury on apple, courtesy of Celeste Welty

Soon these adults will migrate from the fields to structures to seek refuge from the cold temperatures as they attempt to over-winter. If you have lived in Ohio for the past few years, you are no doubt familiar with these large brown stink bugs that invade your home or office in the fall.

While we only have established thresholds for this pest in apples, these were established in the mid-Atlantic and have not been vetted in Ohio yet. We would expect these thresholds to work well in Ohio but research has not been conducted to confirm the results. Monitoring strategies for vegetables, grapes and small fruit can be found here: https://www.stopbmsb.org/managing-bmsb/management-by-crop/

The monitoring system in apples requires two traps, one placed at the edge of an apple block and one placed in the interior. When the cumulative weekly total of both trap catches exceeds 10 stink bugs, an alternate row middle spray for BMSB may be justified. The details are outlined in this article: https://www.stopbmsb.org/stopBMSB/assets/File/BMSB-in-Orchard-Crops-English.pdf

Spotted-wing Drosophila still active on small fruit

Although we are moving toward the end of the season for most small fruit producers, keep in mind that spotted-wing Drosophila populations remain high across the state where traps have been placed on farms. Because of their short life cycle and abundance of ripe fruit, expect these populations to increase up until the first significant frost/freeze event.

SWD larvae in fruit

For growers who have abandoned their small fruit plantings for this year, SWD adults can easily be seen buzzing around ripe fruit as they oviposit eggs beneath the soft skin. Evidence of infestation can be readily seen as soft juicy fruit are filled with white SWD larvae. Even for growers who have maintained a regular spray schedule to control this insect, SWD adults can still be detected flying around bramble and blueberry patches albeit in lower numbers.

Since the threshold for this pest is only one adult per trap, it is necessary to maintain a spray schedule as long as the farm intends to harvest fruit. Once the decision has been made to end harvest, the sprays can be halted.