This is the first winter for my greenhouse, but I would bet the farm that it's going to be below freezing pretty much every night, but warm up during the day. It's this temp swing I'm worried about. Last year I built a box that hung on the side of the house in front of the kitchen window. The box had a glass top and no back. This is the one I was thinking of using. I wintered my more gentle trees in it and left the slider window in the kitchen open about 2 inches to get some heat from the house. My wife, was not impressed. In the past, I have left my trees outside in a box I built out of styrofoam without a lid. I then filled it with leaves in a wind sheltered area. It worked fairly well for most of the trees, but I did loose a few. STA4...are the heating cables you used designed to go under soil or would the type you put on the roof to melt snow work? I would assume the ones for the roof would not have a thermostat. Thanks for the input. Jim

Absolute zero for foliage is different for different varieties. Anywhere from 32 to 15 degrees.Consider absolute zero for foliage to be when the leaves freeze to death. Absolute zero or 55.4F pertains to citrus roots. At 55.4F citrus roots cease to function. You are correct WLD is not a serious problem for trees grown outside. However for trees grown indoors in an artificial situation WLD can be a problem as many, many hobbiest can attest. You seem to generally have a good understanding of the problem. When a citrus tree is placed in a cool room and the foliage is directly in front of a southern exposure a problem can occur. Direct sunlight can easily raise the leaf surface 18+ degrees above the ambient air temperature, depending on the duration of time the tree is subjected to these conditions. If the tree's roots are at 55.4F degrees or lower the citrus roots cannot and do not function. They cannot sent the required water up to the foliage for evaporation to cool the leaves. Even at temperatures closely above 55.4F the root's ability is many times insufficient to properly cool the tree. Many times WLD happens after a very sunny day. WLD rarely happens after cloudy days. Stressbaby, your correct in your thinking. The value of the lights for a tree in the situation that I described above is to keep the growing medium's temperature high enough so that the roots can operate. If your greenhouse conditions are such that the temperatures can keep the roots approximately at 64 degrees then you should not need the extra protection that lights can afford. Unless you are only trying to obtain the maxium growth out of your trees all year around. An example an orange tree in Florida might take 10 years from seed to produce fruit, but the same tree in the tropics might only take half the time. BTW nice home and greenhouse. Your an interesting person, I'm glad you joined the citrus forum. Take care. - Millet

I also hid my switch, sort of. We werent always one to take down our lights. And the kids weren't always one to turn on a switch, and if it didnt produce a light, to turn it back off. They just left it on. So, there were times, in the middle of July, you could see our house across the field, with the Christmas lights on. So I put the light switch in a different place out of the way.

Luvs, Jaybird, there is NO way I'm replacing all those little colored light bulbs. It literally would be easier to take them all off and put on new strings. LOL. I ended up putting all my shiny bright, Radko-like, ornies on it. That is one colorful tree!! And today I put up the little 4 ft purple tree from Walmart, with my purple ornaments. its "different". LOL. As for the wall tree that needed lights strung....this decorating going on the last week is just doing me in with the pain in legs and arms...so to my utter shock, my DH actually said he'd do the lights like I wanted on that little 5 ft tree! I am sure he didn't have a CLUE what he was getting in to. I'm so proud of him tho, he did them just like I wanted and never complained. Even tho he had to make several trips for more lights. There's somewhere around 500-600 on it now, and they are never coming off. LOL. My DH doesn't help with Xmas decor, so for him to do this was really something. He has the patience of a Saint, something I sadly lack. I'd probably have been tearing out my hair before I finished the first string after seeing how long it took. I've been adding the ornies the last few days. When he saw the many boxes of ornaments and my little trees, he said I had too many ornies. I said no way, I just don't have enough trees. LOL. I sure hope to finish decorating this week, its been slow going and frustrating for me. I am taking a lot of pictures, and will do a Photobucket album to share them instead of killing those with dial-up death here. And so far, the Orange Tornado hasn't broken or messed up a thing! Amazing. (Gotta love Pine-Sol. Me, not him! I spritz a bit daily on certain things. Wonder if that company knows its a good cat repellant. LOL) I did take pity on Jazz and gave him a large jingle bell, some ribbon, and a non-breakable ornament. So he's happy enough with that for now. hugs, Karen