Southeast Michigan vegetable update – May 20, 2020

After a day or two of activity, last week’s rainy weather halted field work.


The last week was consistently rainy with heavy precipitation on May 14 and May 24 into May 26. Most of the region reported 3 to 4 inches of rain, though some parts of eastern Monroe County dodged the heaviest rain and saw lower precipitation totals. The next few days will see warmer weather with brisk easterly winds starting mid-day. This weekend will see a rapid warm-up with summerlike temperatures holding through Memorial Day weekend. This will be good for drying things out but going from flooded to hot will likely damage young plants.

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 May 20, 2020


Degree days (base 42)

Degree days (base 50)

5-year degree day average (base 50)

Soil temperature range

Rainfall since April 1






6.65 (+3.68)






6 (+3.66)






6.42 (+3.81)

Impacts of the rain

The last week’s rain events likely caused some preplant nutrients to leach or denitrify. Keep an eye out for yellow leaves, as these are a sign you may need to up your rates at sidedress or move up the timing of sidedressing.

The rain also impacts preemergence herbicides and we will likely see poor weed control and increased accidental herbicide injury. Many preemergence herbicides need to be in the top 0.25 to 1 inch of soil so that it is separated from the crop’s roots. All the rain we had likely pushed herbicides deeper into the soil profile, which will cause damage to the crop, especially transplants. The other effect of this is poor weed control, as the herbicide is no longer ideally placed to take out germinating weed seeds.

For direct-seeded crops that haven’t emerged, soil crusting is a concern. The saturated soils coupled with this weekend’s rapid warm up are ideal for crusts forming. Ironically, one solution is more water, just enough to keep the upper layer of the soil moist so it can’t crust. Another solution is very shallow tillage.

Crop reports

Cucumbers are being planted.

For cole crops, the Deerfield Enviroweather station is predicting peak cabbage maggot flight in the next week. Cabbage white butterflies, the adult form of imported cabbageworm, are flying.

On the weed control side, Command 3ME is now labelled for use in broccoli transplants within 48 hours of transplanting. There may be some bleaching, but crop should grow out of it.

Strawberries are starting to bloom. See Bob Tritten’s east Michigan fruit update for a rundown of what’s going with strawberries post-freeze.

Sweet corn growers should note that high true armyworm catches are being reported in Mid-Michigan and Ohio. Moths likely came in on last week’s south to north airflow. If walking a sweet corn field, look for armyworm feeding, which occurs on the leaf edges and makes the leaf look ragged.

Potato growers, take note of the expansion of new special local needs labels for chlorothalonil.

Every year I get questions about pumpkin weed control. The below table summarizes what is available for pie and pumpkins (not processing pumpkins). It is common to plant pumpkin and winter squash in the same field, so the table also includes where weed control options for these crops differ.

Table 2. Pre-emergence herbicide options for non-processing pumpkins and winter squash on bare ground. *To access the indemnified label, visit website.



Product per acre

Weeds controlled

Application timing


ethalfluralin +

clomazone (Strategy 2.1L)

Pumpkins, Winter Squash

2-6 pints

(for squash, use lower rates in range)

Broadleaves and grasses

Apply within 2 days after seeding.

Needs 0.5 inches of water within 2 days for activation.

clomazone (Command 3ME)

Winter Squash


0.67-2.0 pints

Grasses and some broadleaves: common lambsquarters, common ragweed, velvetleaf

Apply after seeding or before transplanting.

Do not apply under plastic.

Do not use with Jack-O-Lantern Pumpkins, Turban squash, Golden Delicious, and other C. maxima species with pink or burnt orange coloration at harvest.

ethalfluralin (Curbit 3E)

Pumpkins, Winter Squash

2-3 pints

Grasses and some broadleaves

Apply to soil surface within 2 days after seeding.

Needs 0.5 inch of rain within five days for activation. Heavy rains may cause crop injury.

S-metolachlor (Dual Magnum 7.62EC)


1-1.33 pints

Grasses, pigweed, nutsedge, nightshade.

Apply after seeding and before emergence.

Needs 0.5 inch of water within five days for activation; use once in two years on same land.

Winter squash and pumpkins: indemnified label* for broadcast applications.

fomesafen (Reflex 2L)

Pumpkins, Winter Squash

0.5-1 pint

Broadleaves; common ragweed, lambsquarters

Apply after seeding but before emergence.

For transplanting, apply 7 days pre transplant


Use once in 2 years. May cause crop injury, especially if soils are cool. Butternut squash is very sensitive. Water needed for activation. Indemnified label.*

Halosulfuron (Sandea 75 WDG)

Pumpkins, Winter Squash

0.5-0.75 ounce



After crop seeding but prior to soil cracking.


Heavy rain (0.75 inches or more) and cool weather can cause crop injury. Or, can be used post emergence as directed spray between rows, see label.

COVID-19 corner

The USDA’s Coronavirus Food Assistance Program has been released. From the website’s Specialty Crop info page, crop eligibility will be based on the crop and how the program is categorizing loss. Currently, the program is set up for losses that occurred between January and April. Requirements of program highlight how this will be a key year for good farm financial records to document eligibility for potential future programs if losses occur.

Reach out

Please contact me at or 517-264-5309 with questions, concerns or to schedule a field visit. I have the ability to do field visits on a limited basis.

Great Lakes Vegetable Producer’s Network

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

Next week’s show is titled “Pumpkin Planting Secrets Revealed!”

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