Southwest Michigan vegetable update – June 25, 2019

Warm weather returns and we’ve got mixed feelings about that.

Bacterial spot on pepper
Figure 1. Bacterial spot on pepper. Photo by Dwight Sipler,


The 50 degrees Fahrenheit degree-day units are at 714 for 2019 compared to 966 for 2018 and 985 for the five-year average. We had 1.6 to 3.00 inches of rain across the area during the week. Temperatures ranged from 67 F – 84 F for highs and to 48 F – 62 F for lows. Normal highs for this time of year are near 80 F.

Crop reports

Yellow squash and zucchini harvest has begun. Slicing cucumber harvest will begin by the weekend. Watermelon is in early flower and runnering off the plastic.

Early sweet corn is beginning to tassel. Growers indicate plant size is not good so ear size is expected to be smaller. Later plantings show delayed growth but should improve with the temperature increase.

Peppers are beginning to flower, which is somewhat of a concern. Transplanting was late and growth has been slow. Stressed plants flower early and if that flower sets a fruit, it will hinder plant development, which, in turn, will affect total yield. Therefore, growers do not want fruit set on small plants. Some will send workers through the field to remove that first fruit if it sets. It may also fall off on its own in response to increased fertilizer uptake. Bacterial spot (Figure 1) has been found in some plantings. Final plantings will go out next week.

Early blight on tomato leaves
First signs of early blight on tomato leaves. Photo by Scot Nelson,

Early tomatoes have 2-inch fruit and are on their second tie. Early blight is showing up in some plantings. Growers will continue planting through this week.

Early planted potatoes are in flower and all stages of Colorado potato beetle are present.

Garlic scapes are being removed. Removing scapes will increase bulb yield up to 30%. Scapes have culinary uses so they should not just be discarded. An effort should be made to find a suitable market.

Garlic scape
Garlic scape. Photo by Eli Duke,

Early cabbage has 3 inch heads. Larger plantings are at early head formation.

Asparagus harvest is over, but be diligent in scouting for rust and purple spot and control as needed.

Earliest snap beans are in bloom.


Increased temperatures will help plant growth; however, early applied broadcast fertilizer levels have been greatly reduced due to the high amount of rainfall. If possible, growers should apply additional nitrogen. Disease pressure will also increase with warmer weather, especially bacterial diseases. Growers should use maximum rates of disease control products. This is not the year for reduced rates.

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