Humidity

In the wild , the majority of orchids flourish in regions of perpetual mist. Since they are not regular soil-plants , with a proper root system to absorb and supply them with enough moisture from the soil , epiphytic orchids do best in an atmosphere as saturated with water vapour as possible . As a rule they do not thrive in places where the relative humidity is less than 50 % With increase in atmospheric temperature , relative humidity decreases and the plant loses more of moisture to the atmosphere by way of transpiration , resulting in eventual dehydration of the plant . In order to prevent this , temperature should be kept reasonably low and relative humidity high. The most popularly used device for this purpose is the evaporative water coolers. Spraying the leaves, the benches , walls and floor of the orchid house or misting with very fine mist-nozzles are also effective in this respect.