Heating and cooling of the house

Heating of the glasshouses , where it is naturally cool and cooling in places where it is naturally hot , is essential . For purposes of heating , steam , hot air , hot water circulated through pipes , as well as space -heating by electricity , oil or gas , are used. For cooling purposes , evaporative coolers are the most effective . Fine mist nozzles are fitted near ventilators and fans , so that the sprayed water is instantly evaporated . As a rule , air-conditioning is not used in orchid houses , since this depletes the atmosphere of all humidity . If at all they are used , adequate meaures should be provided to compensate for the loss in moisture content. Special package air-conditioners are now available for this purpose .

There are also orchids which can do away with the luxury of an orchid house and thrive in the open , braving the sun , the rain and the winds. The various terete-leaved species of Vanda and their hybrids grow and flower profusely only when exposed to the full sun. So are some of the strap-leaved species of Vanda like V. spatulata ,the aphyllous species of Vanilla , native to South India , V . wightiana , the much cultivated scorpion orchid etc .