Postharvest hopyard considerations

With harvest wrapping up, many growers are thinking about preparing their hopyards for winter and planning for next year.

Chinook hop harvest
Chinook harvest in Michigan. Photo by Michigan Hop Alliance.

Crop summary

The 2020 hop harvest is wrapping up in Michigan and by most accounts, it was a successful growing season. Mother Nature was a great partner this year compared to 2019, when cool and wet spring weather delayed corn planting across the state, which led to European corn borer problems in alternative hosts like hops. There were localized incidents of the European corn borer this year, and there were reports of what is likely hop vine borer. Potato leafhopper and mites were also present. One surprise this year was the prevalence of the pathogen Diaporthe sp., which reduced yields on some farms.

After a cooler spring, warm summer weather kicked the hops into gear and yields looked good. Most Michigan producers have seen average to exceptional yields, with some growers reporting record yields. Growers around the state reported cone color and quality are excellent. Perhaps most importantly, many growers stated that orders have been increasing after a few months of pandemic-related uncertainty.

With temperatures cooling and the bulk of the 2020 crop harvested, focus is shifting to postharvest hopyard management. Postharvest considerations include postharvest pest management, irrigation system maintenance and water testing, equipment winterizing and record keeping. Read on to learn more.

Postharvest pest mangement

Due to the limited winter survival or transient nature of many primary hop insect pests, postharvest management is not likely to substantially impact insect pest pressure next year. Additionally, postharvest fungicide treatments for hop downy and powdery mildew have not been shown to significatly reduce disease severity the following season when compared to traditional practices like spring pruning, protectant fungicides and foliage mangement.

Consider the importance of sanitation at this time. Removing all bines and leaves from the hopyard after the first hard freeze is an important sanitation practice. Plant tissues can harbor insects and disease and should be removed, fully composted, buried or burned. If you did not harvest this year (as in first year hops), remove aerial plant parts after a hard frost to prevent insect and disease carryover into next season.

Also, consider applying herbicides for perennial weed control and removing unproductive or diseased crowns. Lastly, if you are are planning to change over a yard to a new variety next spring, consider herbicide applications this fall to eradicate existing plants.

Irrigation system maintenance and water testing

If you are dealing with irrigation water issues like iron, algae or mineral build-up, periodic irrigation line cleaning is recommended. Consult with irrigation experts to ensure the proper treatment since some treatments may work well but have negative effects—for example, chlorine can kill beneficial soil microorganisms and sulfur can increase salt levels in the soil. Products like Line Blaster can be used a few times throughout the season as a preventative to keep emitters open. Filters at the pump station should be cleaned often; pressure gauges before and after the filter will indicate when a filter needs to be cleaned. Drain or blow out the irrigation system at the end of each growing season.

Even if you don’t experience any water issues, it is important to submit a water sample for a full water analysis. Results of a full water analysis can help you address many water quality issues ahead of time. For example, hard water may reduce fertilizer use efficiency and create potential problems when mixing pesticides. Proper maintenance will improve crop production and lengthen the life of your system. Two excellent irrigation presentations can be found on the Great Lakes Hop and Barley Conference Previous Conferences page under 2017 Conference Presentations.

For more information on irrigation, contact Lyndon Kelley, Michigan State University Extension irrigation specialist, at

Winterizing on the farm

As temperatures drop, broken pipes from freeze damage and electrical equipment failure can result from poor winter preparation of irrigation equipment. Kelley recommends spending time now on your irrigation equipment to help avoid irrigation start-up repairs and delays next spring. Trickle, drip lines and tape are designed to be self-draining, but manifolds and supply systems need attention to make sure no water pockets remain to freeze. Winter rodent damage can turn drip tape and trickle line into junk rapidly. Lines that are to be moved for next year are best stored in the barn. Lines overwintering in the field stand less rodent damage if not covered by plastic, plant material or mulch.

Now is also a good time to inspect each electrical box in the system for damage and holes that may be accessible for rodents. Sealing small holes helps keep rodent damage to a minimum. Both snakes and mice have even been known to crawl into electrical boxes and control panels through small hole or underground conduit with unprotected ends resulting in electrical fire and damage.

Locking down electrical power supplies helps prevent vandals from turning wells and pivots on midwinter and minimizes potential electrical system damage. Now is an excellent time to inspect grounding, system test resistance and make repairs.

To learn more about winterizing your irrigation system, refer to the MSU Extension news article, “Protecting irrigation equipment from winter damage.”

Fall soil testing

Soil testing is a critical step in achieving the desired agronomic, economic and environmental outcomes from fertilizer practices. According to MSU Extension soils experts, there are several advantages to testing your soil in the fall. There is more time available in the fall to collect soil samples and make fertilizer decisions compared to spring. Fall weather conditions are typically more favorable for collecting soil samples. Michigan’s unpredictable spring weather conditions can force postponement or even abandonment of soil testing. If yards require using soil acidifying applications of sulfur, fall applications can take advantage of frost heave and snowmelt to move sulfur into the soil and affect the pH and nutrient availability before bines begin growing again in the spring. Growers may also apply compost fertilizer in the fall and sub-soil between rows in areas in need of better drainage.

Sampling soil
Use a soil sampling tool, shovel or trowel to collect soil samples. Photo by Diane Brown.

Fall may also be a good time to seed in cover crops. Cover crops can offer multiple benefits depending on farm needs and species selection. For example, a fall-planted cover crop may scavenge and store excess nitrogen that can then be disked in the spring to coincide with hop nutrient uptake. Other cover crops can break up a clay hardpan, provide beneficial insect habitat, reduce erosion or help build soil organic matter. “Managing Cover Crops Profitably, Third Edition” is an outstanding free resource that offers detailed management information for many common cover crops. You may also be interested in the Midwest Cover Crop Council’s Cover Crop Decision Tool that helps you select cover crops based on specific needs.

Based on the soil test results, fertilizer can also be purchased prior to the end of the year. Fertilizer is often cheaper in the fall compared to spring when demand is high. Purchasing fertilizer prior to the end of the year could also potentially have favorable tax implications.

Lastly, soil testing laboratories are busier in the spring compared to fall, as a majority of farmers, gardeners and homeowners wait until spring to soil test. A longer wait for soil testing results may force delays in fertilizer timing. There are several good quality labs available to Michigan farmers, including the MSU Soil and Plant Nutrient Laboratory. Details on submission, interpretation, fee schedule and more can be found by visiting the MSU Soil and Plant Nutrient Laboratory website.

Planning for next year

It is well worth your time to set aside a moment to reflect on the season. Take note of trouble areas in the hopyard and consider planning how to address pest or nutrient issues the following season. Also, review your spray records to ensure they are complete and begin investigating a food safety plan for next season. For more information on record keeping, visit the Resources page of the MSU Pesticide Safety program.

This work is supported by the Crop Protection and Pest Management Program 2017-70006-27175 from the USDA National Institute of Food and Agriculture. Any opinions, findings, conclusions or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture.

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