Temperature

Eventhough various species of orchids vary in their individual requirements of optimum temperature , generally orchids thrive in a day temperature varying between 60 to 70 degree F and night temperature of 55 to 60 degree F. Depending upon their preference for a particular range of temperature , the various cultivated species are categorised as cool, intermediate and warm species:

Temperature influences not only proper vegetative growth, but also production of flowers in quite a good number of species . For optimum growth and flowering the night temperature should decidedly be lower than day temperature, preferably by a margin of about 10 F . This is usually so under natural conditions , but in closed orchid houses , it may be a different story altogether. So particular care should be taken in order to provide these ideal conditions. Unless light temperature is kept at a considerably lower level than during the day, the metabolic processes within the plants are not slowed down during the night , the metabolic processes within the plants are not slowed down during the night, with the result that all the reserve food materials are used up in further vegetative growth and no flowers are produced . This is the reason why many orchids of the higher altitude thrive well when brought down and cultivated in the plains , but never produce flowers. Cattleya labiata does not flower when night temperature is higher than 70 F . Most Cymbidium species need a temperature of 50-60 F.During nights and plenty of sunlight during day time , for proper flowering . It has been reported that the pigeon orchid, Dendrobium crumenatum , flowers only in response to a sudden drop in temerature of 10 F . Perhaps this is also the case with such species as Thrixspermum arachnites , Dendrobium haemoglossum, Ephemerantha fimbriata etc. which are also observed to flower greariously . Flowering in certain species of Coelogyne and nobile type Dendrobium is also supposed to be temperature controlled.