The microclimate of higher humidity helps prevent heat stress and aids stressed plants in recovering. Placing a mounted plant in an empty clay pot can help retain moisture around roots. In addition to watering, control of heat and humidity play a significant role in the prevention and management of heat stress. The roots can only absorb so much water at one time. This can instead make matters worse by rotting the plant’s root system, further hampering its ability to take in much-needed hydration. The instinctive response in this situation is to overwater the orchid to correct the dehydration. When that rate of evaporation exceeds the pace at which moisture is being replaced through water taken up by the orchid’s roots, the plant becomes dehydrated - leaves soft and wilted, pseudobulbs wrinkled and ridged. Heat stress is a condition that occurs in orchids and other plants when excessive heat causes an imbalance in transpiration, the process by which moisture evaporates from the plant’s tissues. The midday sun is intense, especially during the summer, and the high temperatures that bright sunshine brings can burn your orchids quickly, especially the more sensitive types such as phalaenopsis, pleurothallids, paphiopedilums and miltonias. Like people, orchids, especially those that prefer cooler, shadier environments, can suffer from heat stress during the hot summer months.

Heat stress wind burn on plants