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

Mine actually seem to flower on and off yearound, but winter or just about now is a frequent period for mine to flower and they are flowering right now. I sometimes think , considering the unusual flowers I could do without them , but I do sort of like them, and surprisingly for plants that are monoecious , mine actually produced some seeds or should I say one of a group of three did, after a summer outdoors. I'd guess some insects did the pollinating, and it's unusual for indoor palms to produce seeds perhaps. The down side was that having planted those very fresh seeds, I must have kept them too wet and not used the right starting mix, and they only rotted instead of sprouting. I'd be watching for the appearance of some very small pea sized almost black seeds , if you do have both male and female in a group planting. Sort of fun!!

Glad to share. I really enjoyed making these. So pretty when done and easy and cheap to do. I used a soldering iron which I found much easier and neater than a stapler. This was posted by Nitty on the hgtv holiday crafts forum. Enjoy! http://www.pbholidayguide.com/festivities/crafts/decorations/light_ball.htm

My biggest disaster was my tree. Instead of my fake pre-lit one,DH insisted he wanted a real tree this year. The Saturday before Christmas,ge was nowhere to be found so I went to the lot alone. Found a bushy round balsam pine for $40 and lugged it home but we couldn't get it to stand up. The tree stand we own just wouldn't work,it kept tipping over. So we dragged it out to the curb, and i went back and got a table top tree for $9. It looks very cute, I was able to put our electric star and two strands of light on it and about two dozen smallish ornaments. Can't post a digital photo, but it was okay. I'm tired of looking at it, I hope to get it down sometime this week. Other than that, Christmas was good, food good, ate a lot, everyone enjoyed their gifts. And Happy New Year. I have my champagne and roast beef ready for tonight. And Eggs Benedict for brunch Jan 1.