Daniel Y wrote:
to add to the above comment. I have 25 plants that where set outside nearly two weeks ago. it has been snowing almost every day since then with the exception of about three days. I don't have any idea what the eventual effect this will have on the plant but they are looking very good considering. a few burns on a couple of leaves where they came in contact with the snow covered plastic that we have over them. but we have not gone to great lengths to protect them. Mainly trying to prevent frost from actually freezing the leaves. They are not growing either so I am concerned that when it does warm up they may just bolt to seed. I am keeping the situation updated in my grow log.
Last year -- my first attempt, which I'd classify as a success) -- my plants took a couple nights of frost and recovered quite well when it warmed up. They complied fairly well with my growth-rate plans, not flowering until after about 2 and a half months. For the record, I covered the flowerheads on one plant of each variety (so I'd have purebred seed for next season) and did nothing about the flowers on the others. They matured a little short (like 4' max), but I attribute that to the very lax approach I took to tending to them... I'm a defiant naturalist; I let them grow the way nature intended.
It'll be interesting to see how your plants end up doing! Good luck