Southeast Michigan vegetable update – April 29, 2020

A cold April closes with steady rain.


A cold April will be capped off with a slow moving weather system bringing rain through our region Wednesday and Thursday, April 29 and 30. Friday and Saturday should be dry days. Early next week will likely bring cooler, Canadian air that will lead to below normal temperatures.

The table below shows rainfall totals for the Michigan State University Enviroweather stations in southeast Michigan, as well as degree-days calculated using the Baskerville-Emin Method. Degree-day average for Commerce and Hudson is over five years, while Deerfield is over three years. Soil temperature range in Fahrenheit at 2-inch soil depth over the last week, and rainfall is in inches. Frozen precipitation is not included. For a refresher on degree-days and how to get this information in your area, see “Accessing growing degree days with Enviroweather” from MSU Extension.

Rainfall and degree day totals as of April 29, 2020


Degree days (base 42)

Degree days (base 50)

5-year degree day average (base 50)

Soil temperature range

Rainfall since April 1



















General information

The Midwest Vegetable Production Guide is now available as a searchable online database. You can find control measures by crop and by pest. There is also a pick my control measure option if you are trying to figure out what to use something you found in the chem shed for. It isn’t an app, so it works well on computers, tablets or phones.

Crop reports

Cole crops have been planted as the weather allows during the last month. These plantings mostly pulled through the assorted cold snaps and snow. The Deerfield Enviroweather station is predicting cabbage maggot will start to emerge early next week, so if you are in an area with a history of this pest, protection should be going on pre-plant or in transplant water in accordance with label specifications for that specific pesticide and specific cole crop. If managing organically, keep your eye on your local Enviroweather station to track when this pest starts to emerge and as numbers ramp up for peak flight. This will help you time putting out a row cover at the right time to keep flies out.

On the herbicide side of things, note that the 24(c) label for Goaltender used post-emergence in cole crop transplants in Michigan has expired.

Potatoes are being planted. Warm winter temperatures means there is a moderate risk of volunteer potatoes surviving this winter.

Greenhouses are full of transplants. The regular bouts of cool, cloudy weather presents management challenges. The basis of controlling botrytis and bacterial diseases that these conditions can promote are environmental management. Managing humidity and minimizing periods of leaf wetness are the goals. Venting can help dry things out and heating the greenhouse even a degree or two can lead to big reductions in humidity. A key person to check in with is whoever is tasked with watering transplants; make sure they are watering the plants as needed instead of at scheduled times regardless of weather. There are also plant protectants labelled for greenhouse use in “Registered Products for Common Greenhouse Diseases on Vegetables and Herbs.”

Soil temperatures in our region are still a bit cold for sweet corn. sh2 varieties like soil temperatures consistently above 60 F, so these varieties should wait until soils warm up. The mild winter our region favors overwintering of corn leaf beetles, Stewart’s Wilt could be an issue this year in susceptible varieties.

Seed corn maggot, which can also feed on cucurbit, pea and bean seeds, peak flight was predicted to be April 27 at the Deerfield Enviroweather station.

Educational offerings

The Great Lakes Vegetable Producer's Network is a live, weekly roundtable discussion during the growing season for commercial vegetable producers in the Great Lakes and Midwest region. It is broadcast live via Zoom at 12:30 ET/11:30 CT every Wednesday from the first week of May to the first week of September. You must register to be a part of the live audience. If you have a pressing vegetable production issue that you would like discussed, simply email it, along with your phone number, to

In the first episode on May 6, the network will interview Amanda Byler, a family nurse practitioner with Great Lakes Bay Health Centers who works with migrant worker communities, and Annalisa Hultberg, University of Minnesota Extension Educator for on-farm food safety. Topics of discussion will include farm family, farm worker and customer safety as we enter our production season during a global pandemic.

COVID-19 corner

The MSU Extension vegetable team has collected useful resources on the COVID-19 pandemic in “Key points and resources to keep vegetable farms running during novel coronavirus.” This resource has been recently updated with Spanish language signage and information about personal protective equipment (PPE).

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