Frost killed covered tomatoes

Asked May 14, 2013, 12:34 PM EDT

Two nights ago temperatures were predicted to go down into the 20's overnight so I covered my planted tomato plants with garden fabric which is supposed to protect down to around 20 degrees. I use this at the end of the season every year and it works great.This is the first time I planted early and thus had reason to use it in the spring. I also had potted tomatoes in a cold frame (plastic walls) which was closed and sitting in a raised bed. I was shocked the next morning to see that all the tomato plants were dead! Why did this happen? Why did the frost get to them through the cold frame or fabric?

Washtenaw County Michigan

1 Response

I'm sorry to hear about your tomatoes. Tomatoes and pepper are very sensitive to cold temperatures. Your fabric cover tested "to around 20 degrees" . may have been under ideal conditions Sunday night/Monday AM were far from a simple cold night. The freezing temperatures lasted several hours with winds over 10 miles an hour(wind chill factor). Temperatures recorded at the AA airport was a record breaking 22 degrees. The last low temp was 27 degrees on this date in 1996.
I'm suggesting weather conditions had a lot to do with the failure of you fabric.
The cold frame frost may have been caused by a build-up of moisture with-in the enclosed frame. When outside temperatures get so low heat is sometimes
drawn out of the soil. Fortunately, it is early enough for you to replant. The freeze risk date in Michigan is actually May 28th so be cautious. Often a mulch around the plant will help to prevent heat loss and preserve moisture. Doubling the fabric cloth may have given your tomatoes a little more protection..