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On Wed, 25 Aug 2004 15:48:26 GMT, K Barrett wrote:
"Myrmecodia" wrote in message om... "K Barrett" wrote in message news:kMSWc.39230$9d6.6767@attbi_s54... Name one orchid that doesn't want at least a 10 degree change in day/night temps in order to flower. Want or need? Off the top of my head... Phalaenopsis bellina and P. violacea Chiloschista lunifera Psychopsis papilio Oncidium Gower Ramsey Cattleya walkeriana Paphiopedilum (various mottled leaf species) Polystachya pubescens Polystachya vulcanica Brassia verrucosa Dendrobium antennatum Cirrhopetalum curtisii Sophronitis cernua Neostylis Lou Sneary Stenoglottis fimbriata All bloomed reliably for me under lights without a significant temperature drop at night. I'd suggest that the majority of lowland tropical orchids do not require a temperature drop to initiate blooming. Blooming could be triggered by a variety of stimuli: increased light simulating defoliation of deciduous trees in the dry season, reduction in watering, subtle changes in day length, or simply maturation of the newest growth. Plants from monsoonal climates are probably more likely to bloom in response to cooling. Some orchids do bloom reliably after a sudden drop in temperature (Dendrobium crumenatum, for example), and certainly a temperature drop in the autumn may help others (cymbidiums, hybrid phals) to spike, but there are lots that don't require it. Since cooler temperatures in the autumn usually come bundled with shorter days and reduced fertilizing, I think its unclear exactly what the plants are responding too. Orchids that are CAM plants may require a temperature drop for efficient photosynthesis, and highland tropical plants will want cooler temperatures at night. But those are daily, not seasonal, requirements and are not directly linked to initiation of blooming. Nick -- Well I'm not going to dig my heels in on this point, and I will admit I learned something, but I'll still bet that in nature its cooler at night than it is during the day whereever these orchids come from. And was the original poster talking about any of the plants on this list? K Barrett Kathy, you are spot on! What happens when the sun goes down? Cheers Wendy |
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