put some mass (jugs of water) in there that will retain the heat, or throw a blankie on it at night?

Rob

Check out post by Hudson in his thread GH tomatoes.
He is using 100W light bulbs...see his GH photos, last post (March 21).
I like all of his ideas.
Blanket should work well for you too as Lori mentioned.

Rina

This post was edited by rina_ on Fri, Mar 21, 14 at 23:23

Thanks Rina! I don't know how cold your night time temps are Rob but the 100W light bulbs with a double thick frost blanket have kept our tomatoes above 40 degrees with inside GH temps as low as 15 degrees (outside GH temp was -4 degrees that same night). It appears to be a good option if you have power to your hoop house.
Hudson

I just bought some of that same mushroom compost. Mine came from Menard's :)

As was mentioned above, you could put a tarp over your entire structure on cold nights. The more layers of cover you have, the better. A frost blanket over the ground itself would also help ward off a freeze on a cold night.

OK, I'll try the bulbs as I can run electricity with no problems. It has been crazy as far as night time temps go but I hope we are past single digits... we all hope. Thanks to all !!

Would heating the soil, say with buried cables, produce enough radiant heat to keep the air warm?