Hi All, Thank you for your comments. By adding your experiences and knowledge to the post, we all gain from your insight. The more discussion the better. I'll try to add a few more pieces to the puzzle. History: Garner and Allard of the USDA (accidentally) discovered photoperiodism in plants during the 1920s. They were studying how to grow better tobacco. Unfortunately, their plants failed to bloom in the field. In fall, as frost approached, they quickly dug up the valuable crop and moved it into a greenhouse. As the daylength decreased, the tobacco bloomed. Photoperiodism! Moral of the story: Even a poorly designed experiment can yield important results. Garner and Allard went on to describe three groups of plants; Short Day Plants, Long Day Plants, and Day Neutral Plants. Most of the following experiments focussed on food crops (soy beans, onions, strawberries, potatoes, radishes, yams, etc). Only a handful of garden flowers and houseplants were tested (dahlias, chrysantheums, Easter lilies, poinsettias, etc). Very few orchids have been tested. Clint posted an excellent list of short day orchids. I wonder if there are more that others know about. Please add to Clint's list. # # # Mehitabel, I always have reasonable doubt about my experiments :-) You raised some great issues. I'll try to comment. There are two parts to the photosynthetic reaction in plants: light reaction and dark reaction. Blackman, an English physiologist, discovered that part of the reaction required chemicals, enzymes, and CO2, but it did not require light. He coined this as the dark reaction. Unfortunate wording tends to make you think that this reaction only occurs in darkness, which is not true. This part of the photosynthetic reaction does not require light, but neither does it require darkness. Great concept, poor choice of naming. Many commercial greenhouses grow stock under continuous 24 hour lighting conditions. Nearly all commerially grown annual flowers are grown this way. Lesser so for other crops. Again, few people have ever researched this topic with orchids. Mehitabel, I do have a whole bunch of botany degrees hanging on my walls to keep my wallpaper from yellowing. It's merely my poor writing skills that keep me from expressing my observations properly. My fault. I tend to get all excited about growing plants, but then fail to get all the words right. What I meant to say is that some plants do require a period of darkness to flower. Some plants grow better (metabolism) with a period of darkness. But some plants grow just fine under continuous 24 hours of light and these plants are not hurt by lack of darkness. I wonder which way orchids grow best, and flower best. Can orchids be grown under continuous light (longterm) without hurting the plants. Great points Mehitabel. # # # Terpguy, thanks for your comments. I agree, we should not recommend that everyone start growing under my experimental conditions. However, if someone would like to sacrifice a few orchids under continuous 24 hour light conditions for a few months, and then report back to us - that would be great. If you get an orchid to bloom, you have just found another species that is not a short day plant. Perhaps someday there will be a long list of tested species and we can all benefit from the shared knowledge. You don't need a fancy lab to run this experiment. You just need to keep the lights on. # # # To the other readers, jump in and share your knowledge with us. If you have observations about growing under warmer winter minimums and/or growing under continuous lighting conditions, we would love to hear your experiences. Tom

What is it doing?. the sun is shining as per usual. If you want to go for a swim in the ocean the water temperature is about 22C. You could of course lie on the sand but i think that is a pretty boring exercise. The conditions in this room are 68% humidity 25C . As for the fall, mostly only introduced trees lose their leaves so you do not get those glorious colours on the trees as per NE USA. Outside at 5:36pm it is 66% humidity,temp 26C. i can see a fig tree, an olive tree, a banana herb with fruit, a crepe myrtle in bloom, a lemon tree, a lime tree, a jacaranda tree, two tall eucalpytus and in the distance a fugly palm tree. Only the crepe myrtle will colour up for autumn. In the front of the house, the trees lining the street are evergreen brush box. Hated by everyone when they drop old leaves in early summer. but good to park your car under when the day is hot. Snow, have i mentioned in old posts how much i hate snow. Thank goodness it never, ever snows here.

What is interesting from some longer term research studies with unheated structures is that on a few nights the inside temps would drop below the outside temps. I won't go into the explanation given but to know that wierd things happen just reinforces the need for an aggressive heat source when attempting season extension.

I believe this is what has sparked the second spikes this year: the AC in my building kicked in for the summer, so even though the long, warm days are here, the temps in this room have dropped considerably. The next temperature swing will be in February, which coincides with lengthening after days after winter ... I think this is how I've ended up with two bloomings per year, and spikes that grow more buds one month after the first series of buds have opened. I feel like a greenhouse tricking orchids to bloom out of season (except I'm not 100% sure how I'm doing it, lol!). Oddly, my office had been in a south-facing, evenly temperate location down the hall for 7 years, and this never happened. My orchids faithfully had one bloom every year at the same time. Now I'm in an east-facing location, and the temp is all over the place, and it's a circus up in here, I'm never sure what to expect!