When can I put my lettuce out under hoops?
I was hoping for some advice on putting out some lettuce I started indoors early. Right now I have about 20 lettuce plants growing indoors of various sizes. They are cold hardy varieties like romaine and winter density lettuces. Some are smaller, some are getting quite large, in fact I keep a video journal at www.youtube.com/robwasnj My question to the forum is how long do I need to harden these off and then how early can I put them out in the garden under my hoop tunnels? I wouldn't be heartbroken taking a chance and losing some plants since I've been planting them every week or so but at the same time I'd not want to sentence them to certain death if someone here knows better than to put them out when nights are dipping below freezing. I do have some christmas lights as well that I could hang under the hoop tunnel as well.
Thanks for any feedback,