Preparing for Winter: A Guide for Vegetable Farmers

from Organic Broadcaster | September 2022 | Volume 30, Issue 5

News Briefs

PREPARING FOR WINTER:

A GUIDE FOR VEGETABLE FARMERS

bY NATALIE HOIDAL

After an especially hot summer, it’s easy to feel burnt out at the end of the season and to want a break from thinking about farming. Before taking some time off, there are a few important things that growers can do to make life easier when next spring arrives.

TAKE TIME TO GATHER YOUR NOTES FROM THE SEASON

Have you ever made a list of mental notes during the growing season and promptly forgot it by the time February rolls around? I have done this more times than I’d like to admit. Before the season is over, take a walk through your fields with a notebook and write down a list of all the insect pests that caused you trouble this year, any diseases you noticed, varieties that seemed to perform better than others, and notes about things like mulches and row spacings. So many of the issues that we deal with on farms are best addressed preventatively with things like resistant varieties and preventative pest management plans. By taking the time now to note exactly what you’re dealing with, you can develop better management plans for next year. worked at a farm for a couple of years with a giant map of the farm on the wall covered in plexiglass. Crew members were asked to write notes on the board about things they noticed in the field, and each week we met for 15 minutes to review what we noticed that week. The manager took photos of the board each Friday and committed these photos to a notes folder, which he reviewed each winter. Different people noticed different things, and our weekly brainstorming and discussions led to quite a few management improvements on the farm. Even if you’re not doing this regularly, a brainstorming session at the end of the season may provide valuable insights.

Finally, make sure you’re correctly diagnosing problems. Disease problems and nutrient deficiencies can be very hard to distinguish using just your eyes and online tools. For significant issues, consider sending samples to your local diagnostic clinic or submitting tissue samples to your local soil testing lab for foliar nutrient analysis. This will help you ensure that you are selecting the correct resistant varieties and inputs for next year.

SqUEEzE IN COVER CROpS WHEREVER YOU CAN

When I speak with farmers who are developing climate resilience goals for their farms, almost everyone wants to prioritize planting more cover crops. However, when you’re busy harvesting, weeding, and getting crops to market, cover crops can easily fall to the bottom of the to-do list.

While cover crops are important for long-term soil health, there are also some concrete ways they can help lighten the load next spring. The US Climate Resilience Toolkit reports that across the Midwest, we are seeing heavier rainfall events and more precipitation overall. Over the past few years, farmers have struggled to get into fields on time due to excess soil moisture. One University of Minnesota study led by Dr. Cindy Tong is exploring the practice of preparing beds in the fall and planting cover crops between beds with the goal of absorbing excess moisture and allowing for earlier spring planting. While the study is ongoing, preliminary data from 2022 showed that plots with a rye cover crop between beds had less soil moisture in the spring, allowing the researchers to enter the fields earlier and under less muddy conditions than in plots with weed barrier fabric or bare soil.

A fall cover crop can also provide nitrogen for spring crops. A common problem I see on organic farms is that the sources of fertility, organic growers have access to often don’t match the nutrient needs of crops. Composted manure is a common fertilizer among vegetable farmers and it tends to have a high phosphorus to nitrogen ratio. This can result in phosphorus build-up in the soil and can make it challenging to meet the nitrogen needs of crops while keeping soil phosphorus at a reasonable level. Cover crops are an excellent way to add nitrogen to your fields without the excess phosphorus or potassium. Depending on the species, amount of time you allow your cover crops to grow, and stand density, cover crops can potentially

provide over 100 pounds of nitrogen per acre. The University of Minnesota Small Farms YouTube channel has a video showing how to calculate the amount of nitrogen you are getting from a cover crop. The SARE publication “Managing Cover Crops Profitably” is another great tool for this. Estimating your nitrogen credits now will provide insight as you develop nutrient management plans over the winter.

In my experience working on farms and learning from other farmers there are a couple of strategies that seem to help prioritize cover crop management: one is to write cover crops into your succession plans instead of simply hoping to find some time at the end of the season. Another is to make cover crops someone’s job duty (this is more practical on a larger farm with a large crew). Just like it might be someone’s job to take care of the cole crops or the solanaceous crops, assigning cover crop duties to a specific person can help them to remain high on the list of priorities.

TEST YOUR SOIL IN THE FALL

While it’s technically fine to test your soil any time, fall is a great option for specialty crop growers. Testing in the fall provides ample time to receive your results (which can often take a few weeks to arrive), develop a nutrient management plan, and order inputs. If you would like assistance reading your soil test or developing a nutrient management plan for your farm, Extension is available to support you. This looks a bit different from state to state; some counties have local Extension educators to support growers with a wide variety of production related topics. Other states have educators with statewide responsibilities that support growers with specific needs. Most state Extension programs have a general information line where you can ask about how to best receive support for your needs. Most Extension programs also have a state-specific nutrient management guide for specialty crops that walks growers through the steps of analyzing soil test reports and making management decisions accordingly.

Each fall I receive questions from growers about how they should go about testing soil on a very diverse farm. On a farm with 20 different crops, it can be challenging to decide how many different tests are necessary and how to group fields. For the most part, as long as you are consistently rotating crops, it’s ok to take an average from multiple fields. That said, there are reasons to take separate samples from different parts of the farm. If the soil texture varies considerably across the farm, if one area is on a slope while another is in a valley, or if one was historically managed differently from the other (e.g., one area received manure for many years or was cover cropped regularly), these are all good reasons to assess different areas of the farm separately. Another approach is to ask yourself how you will actually use the information from your soil tests. If you will realistically manage five different sections on your farm differently based on soil test results, then it might be worth taking five different tests. However, if you are likely to use the same practices across the whole farm, then it’s more practical to do one combined sample. If you’re more of a visual learner, we have a video that covers this topic on the UMN Extension Small Farms YouTube channel.

TAKE TIME TO REVIEW pOSTHARVEST GUIDELINES

Every winter we get calls from growers whose potatoes or squash are rotting in storage. Taking time to review the storage requirements of the different crops you grow and culling damaged vegetables that may spread diseases in storage can help to prevent these problems.

Root and bulb crops like potatoes and carrots are easily bruised and cut during harvest. Proper curing helps to reduce damage, but is not a substitute for taking the time to sort through produce and remove damaged fruit, tubers, bulbs, etc. Once in storage, diseases can spread rapidly, so taking out the major sources of inoculum is an important preventative practice.

In general, there are three groups of vegetables with very different storage requirements. Group one does well with cold temperatures and high humidity (32 degrees Fahrenheit, 95 percent relative humidity). This group includes apples, asparagus, beets, broccoli, carrots, herbs, leafy greens, leeks, and peas. Group two does well with cool temperatures and high humidity (40-50 degrees Fahrenheit, 95 percent relative humidity). This group includes beans, cantaloupe, cucumbers, eggplant, okra, peppers, potatoes, and summer squash. Group three does best with cool temperatures and low to moderate humidity (40-50 degrees Fahrenheit, 50 percent relative humidity). This group includes pumpkins, onions, and winter squash. For more specific guidance, UMN Extension has a postharvest handling webpage (Postharvest handling of fruit and vegetable crops in Minnesota) with recommended temperature and moisture guidelines for the major vegetable crops grown in the Midwest.

SET ASIDE SOME TIME TO ASK THE BIG qUESTIONS AND REFLECT TOGETHER

Every year brings a new set of challenges and questions. At least in Minnesota, in 2019 the main challenges were related to excess water. In 2020 they were pandemic related. In 2021 they were drought related. So far 2022 seems to be a mixed bag. Each new set of challenges brings big questions about things like major infrastructure investments and changes to business models. Spend some time asking questions like: What did you enjoy the most about this farming season? What aspects of farming made you feel burnt out? What would save time and allow you to prioritize the things that you had to put on the back burner this season?

Finally, finding time to reflect in community with other growers is invaluable. When I started my job as a vegetable crops educator in 2019, I traveled around Minnesota asking farmers what they needed most. While everyone had specific needs like support with disease management or more information about variety selection, I was surprised by how many farmers told me that what they need most is a stronger sense of community. There are so many ways to connect with other farmers; whether it’s a local chapter of a farming nonprofit in your state, attending conferences, or signing up for educational cohorts. If you can’t find the type of community you’re looking for, don’t be afraid to reach out to your local Extension educators or farming nonprofits. We are often looking for new ways to connect with and support growers, and hearing from farmers helps us develop programs that meet farmer needs.

Natalie Hoidal is a University of Minnesota Extension, Local Foods, and Vegetable Crops Educator.