East Michigan vegetable update — April 25, 2018

It’s been a slow spring for field activity.

Grafted tomato, with scion developing a small adventitious root. Photo by Ben Phillips, MSU Extension.
Grafted tomato, with scion developing a small adventitious root. Photo by Ben Phillips, MSU Extension.

Weather

What a slow spring. We are two weeks behind the five-year average in terms of growing degree-days (GDD). There has been very little field activity. Some pre-emergent herbicides are being applied, along with fertilizer and bed preparations.

We should be catching a nice break this next week when the wind shifts to a southwesterly flow bringing warm air up north. Tomato hoophouses will probably open all sides next week, with predicted temperatures in the mid-70s and sunny.

The following table shows GDD base 50 degrees Fahrenheit since March 1, rainfall accumulations in inches since April 1, and soil maximum temperature ranges (top 2 inches) over the last seven days from Michigan State University Enviro-weather stations in the region.

Rainfall and GDD totals as of April 25, 2018

Location

GDD

GDD five-year average

Rainfall

Rainfall five-year average

Soil temperature range

Emmett

23

70.0

2.34

1.80

35 - 62

Fairgrove

29

69.8

2.56

2.78

34 - 54

Flint

34

99.4

3.02

3.13

38 - 52

Frankenmuth

29

77.9

2.81

3.54

36 - 49

Freeland

23

64.2

2.66

3.86

33 - 43

Lapeer

29

89.7

3.63

2.89

38 - 57

Linwood

15

50.0

3.81

4.05

34 - 52

Munger

17

62.0

1.14

3.15

34 - 53

Romeo

27

92.9

2.77

2.13

32 - 50

Sandusky

20

57.8

3.24

2.95

33 - 46

Crops

Seeded onions and transplanted sweet onions are being planted as soils allow. Many growers are still getting onion starts from Texas, Georgia and Arizona. If starting your own transplants this year, be aware that a finger-style transplanter you might use with bare-root starts can sometimes be gummed up by the soil plug in a cell-transplant onion.

Transplanted field lettuce has begun and has been continuing as conditions allow.

Garlic is 6-8 inches tall. Mulch has been removed on many farms.

Strawberry mulch has not been removed at the vegetable farms I have visited. Leaf development has been slow.

Asparagus is still below ground.

Heated hoophouse tomatoes are between 0.5 and 3.5 inches in diameter. Plants are on their third or fourth flower cluster in the oldest plantings. One grower reported an 80 percent success rate grafting tomatoes for the first time this year. Be careful maintaining a 100 percent humidity environment for healing them, and keep the scion from rooting once they are transplanted into beds.

Pollination has been a topic of discussion. Growers are reporting blossom drop all across the Midwest and are thinking maybe it's the bumble bees working the flowers too hard. I think it is more likely a temperature issue or a fruit load regulation due to plant size. The plant knows how many fruit it can carry and will routinely drop blossoms that it doesn’t want to develop if it is already allocating resources to fruiting. As the plant gets bigger, it can allow more fruit to develop.

There can also be nutrient triggers for blossom drop, including boron, manganese, zinc or nitrogen deficiencies. Too much nitrogen can also reduce flowering all together. The University of Florida bulletin #HS1195, “Blossom Drop, Reduced Fruit Set and Post-Pollination Disorders in Tomato,” has some explanations of primary and secondary reasons for blossom drop throughout the season

Brassica transplants are ready to go at many farms and plastic is laid. Cauliflower was slated for transplanting in Cass City, Michigan, on Tuesday afternoon, April 24. I have seen some damping off issues.

Vine crop transplants were breaking the surface in transplant trays this week. Field tomato and pepper transplants have two leaves.

Be aware of tomato transplant bacterial issues in the greenhouse. Keep air moving and vented to reduce the amount of time water droplets stay on the leaves. Streptomycin is only labeled for greenhouse use on tomatoes and is an effective tool for reducing bacterial pressure before field transplanting. You are not allowed to use Streptomycin on field tomatoes, so use it now if it is needed, mixed with copper.

Need your water tested for the Food Safety Modernization Act (FSMA)? Check out the Michigan Ag Water Lab Map.

Please contact me at phill406@msu.edu or 616-901-7513 with questions, concerns or to schedule a farm visit. You can also send plant materials to MSU Diagnostic Services.

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