Michigan vegetable crop report – April 30, 2025

Benjamin Phillips<benp@msu.edu>, Benjamin Werling<werlingb@msu.edu>, Chris Galbraith<galbra53@msu.edu>, Salta Mambetova<mambetov@msu.edu>, Lyndon Kelley<kelleyl@msu.edu>, Mary Hausbeck<hausbec1@msu.edu>, Zsofia Szendrei<szendrei@msu.edu>, Zachary Hayden<haydenza@msu.edu>, Daniel Brainard<brainar9@msu.edu>, Jeffrey Andresen<andresen@msu.edu>, Vicki Morrone<sorrone@msu.edu>, Jaime Willbur<willbur1@msu.edu> and Jan Byrne<byrnejm@msu.edu>, Michigan State University Extension -

This is the first weekly report of the 2025 season.

A bare field where onions were recently transplanted.
Photo by Salta Mambetova, MSU Extension.

Weather

The upcoming week’s forecast calls for partly sunny and cool Wednesday (April 30). Showers and thunderstorms will develop in the west overnight, continuing Thursday through early Friday. Fair and cooler this weekend. High temperatures from the 40s north to 50s south Wednesday. Warmer Thursday with 50s to the north to low 70s to the south, then cooling back to the 50s to 60s again this weekend. Low temperatures from the upper 30s in the north to mid-40s south Thursday and Friday, with 30s to the north to 40s south this weekend. Frost is possible Saturday and Sunday mornings across some northern sections. Medium range outlooks call for warmer and drier than normal weather for much of the first half of May.

Chlorpyrifos update

“Use it or lose it!” is the theme for chlorpyrifos in all vegetables except asparagus. Chlorpyrifos may be applied legally in labeled vegetables until June 30, 2025. Following that, asparagus in Michigan is the only vegetable use that will be retained. Read more in “Veggie chlorpyrifos update for 2025” or on the EPA website.

Crop updates

Tillage, cover crop termination, early season weed control, fertilizer spreading, soil testing, planting, tilling, hardening off transplants, watering, seeding transplants, spring plant sales, finishing farm construction projects, getting machinery ready—farms are a buzz of activity and we here at Michigan State University Extension love to see it.

As things get rolling, we wanted to share some good articles that may be helpful.

For those terminating cover crops on a smaller scale, this Natural Resources Conservation Services resource may be helpful for navigating your options. 

Many vegetable growers rely on the H-2A program for sourcing labor. Michigan State University (MSU) Extension recently published an article on the program.

A comprehensive report on the specialty crop industry, its threats and the implications of possible future contraction, was released recently - read the full report here.

Also, check out this newer article on how irrigation can influence herbicide activity.

Asparagus

Harvest started late last week through Monday in southwest and eastern Michigan and will likely commence within the next seven to 10 days in west central Michigan.

The Brainard lab at MSU has been out on farms this spring calibrating a weather model for predicting asparagus emergence. This year, soil temperatures have varied a lot across production regions (see below figure), resulting in a wide range of predicted harvest dates. In the southwest (e.g., Benton Harbor), soils warmed up relatively quickly and commercial asparagus harvest began late last week. In Oceana County, we have had a pretty typical spring warmup and our growing degree day (GDD) model currently predicts May 2 for emergence of ‘Millennium’ at the Hart research station, with commercial harvest expected three to seven days after that (May 5-10). However, keep in mind that the actual time of emergence will vary a bit based on variety (e.g., ‘Sequoia’ and ‘Eclipse’ usually emerge a few days earlier), the depth of the crown (shallower crowns emerge faster), ground cover (e.g., rye cover crops can slow emergence by one to three days) and the aspect of the field (south facing slopes warm up earlier).

A line graph showing soil temperature degree days after estimated bud break.
Soil temperature data for predicting asparagus emergence. Our MSU asparagus emergence model predicts emergence based on soil temperatures from Enviroweather stations. This is done in two steps. First, soil temperature data from 8 inches is used to predict below ground bud break. Second, soil temperature data from 4 inches is used to predict when spears emerging from buds will grow long enough to poke through the soil surface. Graph created by Dan Brainard, MSU.
'Millennium' asparagus head emerging from the ground.
Spears of Millennium at the West Michigan Research Station. Photo by Dan Brainard, MSU.

After a possibly frosty weekend it should warm up. The NOAA outlooks for May 5-13 call for warmer than normal temperatures, thanks to a ridge in the jet stream. Hopefully we will not get a freeze when big pickings arrive!

Brassicas and greens

A long, red trailer filled with trays of cabbage transplants, with a hoop house and red bard in the background.
Cabbage transplants hardening off prior to planting. Photo by Chris Galbraith, MSU Extension.

Cabbage, collards and other brassicas are being transplanted in the field. Dill and other herbs have been seeded. Brassicas planted in early April that had not been hardened off beforehand showed some freeze damage. High winds in recent weeks caused some stress to young plants from whipping and blowing sand. Fields where conservation tillage was used and greater residues remained on the soil surface had less blowing sand, which was easier on the vulnerable plants. Winter greens in high tunnels are winding down while spring greens are growing well.

As temperatures rise and GDD accumulate, cabbage maggot activity becomes more of a risk. For leafy and heading brassicas, cabbage maggot damage is worse on younger plants early in the season. Verimark can be applied as a tray drench to transplants to provide effective control. It will also provide early season flea beetle and caterpillar control.

Alternaria and clubroot are cole crop diseases that are seen on farms year after year. MSU Extension hosted webinars on both of these diseases over the winter: recordings of these webinars and others can be found at the MSU Vegetable Extension YouTube page.

Carrots and celery

Sowing of processing carrots started a few weeks back. Celery planting is now ongoing.

Strong southerly winds in the lower part of the state may have brought up migrating aster leafhoppers early this season. Given the weather patterns, it is unlikely these migrants reached more northern areas. We will learn more once scouts begin sweeping.

Cucurbits

Cucumbers and squash transplants are being seeded. Melon transplants are growing in the greenhouse and waiting for warmer weather. High tunnel cucumbers are being planted.

Fruiting vegetables

A greenhouse full of tomato transplants in trays sitting on top wooden planks.
Greenhouse full of tomato transplants for retail. Photo by Chris Galbraith, MSU Extension.

Heated tunnels are full of tomatoes at flowering stage and fruit set. Field tomatoes will begin to be planted over the next few weeks.

Thrips can vector viruses to pepper and tomato plants in the greenhouse, namely tomato spotted wilt virus and impatiens necrotic spot virus. Thrips in the larval stage may acquire the virus while feeding on infected plants, after which the virus survives and reproduces within them and can be spread to other plants through feeding when the thrip has reached the adult stage. Adults cannot “catch” the virus as adults, only larvae. Flowers and ornamental plants may act as a host for these viruses and for thrips. Whenever possible, avoid growing vegetable transplants—especially Nightshade family crops and lettuce—in the same greenhouse as flowers.

This past March, MSU Extension partnered with Ohio State University and Purdue University to put on a High Tunnel School simulcast across the three states at multiple locations. If you love to learn about hoop house growing but missed this program, don’t fret. The full recording of the event is available at Tri-State High Tunnel School.

Tomatoes growing in a greenhouse with possible ethylene injury.
Possible ethylene injury in greenhouse tomatoes. Photo by Salta Mambetova, MSU Extension.

Ethylene injury has been observed in greenhouse tomatoes. Fluctuating temperatures may have led to extended heater use and reduced ventilation, contributing to the issue. “Prevent ethylene and carbon monoxide from occurring in your greenhouse” explains symptoms of ethylene and carbon monoxide issues in the greenhouse and how to avoid the concern.

MSU Extension recently put out an updated article on identifying different abiotic and biotic diseases in tomatoes.

Onions and garlic

Direct sown onions are growing, and transplanted onions and shallots have been going out. Garlic is up and growing.

A bare field with onion transplants sticking out.
Onion transplanting on April 22 in Bay County. Photo by Salta Mambetova, MSU Extension.

Root crops

Turnip sowing began back in late March/early April, with radish sowing starting up in the last week. Chlorpyrifos can be used to protect these early plantings against cabbage maggot. Legal use ends June 30, so use existing stocks now. Potatoes are being planted.

Strawberries

Do you have black root rot on your farm? You can protect against one of the black root rot pathogens, Rhizoctonia, at planting time. Strawberry roots can be soaked in the fungicide Abound (azoxystrobin) prior to planting, see the label for more information. Note, however, that the exact pathogen responsible for black root rot can vary from place to place, making diagnosis helpful, since different fungicides/nematicides work for different culprits. If you see symptoms on your farm, send a sample to MSU Plant and Pest Diagnostics. Learn all about black root rot in this YouTube video.

A strawberry showing winter damage cut in half.
Strawberry plants showing signs of winter damage. Such damage can hinder plant growth, reduce yield and potentially result in misshapen fruit. To mitigate this, avoid applying high levels of nitrogen in the fall and winter. Use row covers or straw to protect plants from desiccation and extreme cold in the fall/winter time. Photo by Salta Mambetova, MSU Extension.

Sweet corn

Fields are being seeded and even some transplants are being produced in the greenhouse. Mice digging up sweet corn seeds from transplant trays in the greenhouse to feed on them can be a problem, even with treated seeds. One attentive grower noticed that once the corn seed has germinated and the radicle has emerged, mice may leave the seeds alone and seek out more nutritious morsels. Germinating flats in the protection of the germination chamber before moving them out to the greenhouse can dramatically cut down on seed feeding by mice.

Produce Food Safety On-Farm Readiness Reviews

Schedule an On-Farm Readiness Review today for a two-hour educational visit that takes place during the harvest season and is meant to be casual and low stress. Everything discussed during an On-Farm Readiness Review is confidential and focuses on ways to reduce risks in relation to produce safety. There is no pressure to take our advice either, we are just here to support you in your produce safety efforts.

Events

 

This work is supported by the Crop Protection and Pest Management Program [grant no 2024-70006-43569] 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.

This article was published by Michigan State University Extension. For more information, visit https://extension.msu.edu. To have a digest of information delivered straight to your email inbox, visit https://extension.msu.edu/newsletters. To contact an expert in your area, visit https://extension.msu.edu/experts, or call 888-MSUE4MI (888-678-3464).

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