How cold is too cold for seedlings

[recruiterg]

It is supposed to be 36 degrees tonight in Minneapolis. Many of my seedlings are small and are in the cold frame in the back yard. Should I worry?

[nctomatoman]

Nope. I've had mine outside down to 33-34 degrees - if it is that close, I cover with Reemay. And it happens most springs to me, typically...and always creates anxiety!

Not until all threats of frost have past. Good rule of thumb is 2-weeks past your areas average last frost date.

[nctomatoman]

With no greenhouse and thousands of babies in my driveway, I've no choice but to do the "test" on a pretty large scale...the only variety that seems to really get annoyed a low (not frost, but mid 30s) temps is Sungold, for whatever reason!

Wind driven cold rain makes the seedlings look far worse than calm cold.

[recruiterg]

Thanks Craig. I thought I had seen that in another post. I'll assume things will be ok since they are protected from the wind and rain.

[Granite26]

Boy the cold has really slowed plant growth here. In a streak of cold cloudy days it seems like the toms just dont budge. My plants are in a homemade grenhouse of 2x4's and plastic. The temps have been low 30's many times the last few weeks and I have been worried as outside it got down to 19 one night but I held in the enclosure. Then the sun comes out and it hits 80-90 in there.
Good luck with the cold temps!

[nctomatoman]

What I suspect is that when it is cold, the root development is proceeding but not much happens upstairs...but when it does finally get warm, they really shoot up. I am amazed particularly at the slowness of development of the Chinense chiles (the Hab family) until it really gets warm. they do just sit there and sulk in the cold! Eggplant are obviously not thrilled either.

[feldon30]

Keyword is "cold frame" if you have your plants in a mild greenhouse type setting that can help a lot. If you have an extra thermometer that's been calibrated, I'd put it in your cold frame out of sunlight and see what the temps are showing.

Craig,

I also believe that with the warm soil in Houston, even though the plants above ground are rather grumpy on 40's and even 50's days, the roots are taking off. Up north, it may not help as much to plant early, as indicated by the many stories of plants going in later catching up to ones already in the ground.