Those new to growing orchids will be relieved to know that most do well at normal indoor temperatures, and lower nighttime temperatures don’t impede growth. In fact many orchids need a fluctuation in temperatures to encourage blooming. The specific temperature requirements and necessary temperature fluctuations vary by type of orchid. But there are some general guidelines that you can follow to keep your plant healthy and encourage blooms.
Comfortable indoor temperatures are generally acceptable for growing the most common types of orchids such as Cattleya, Phalaenopsis, Paphiopedilum, Oncidium, and Miltonia. As a rule of thumb, if it feels comfortable to you, these plants will do fine. Daytime temperatures between 65ºF and 80ºF are usually best, with nighttime temperatures between 55ºF and 75ºF.
Some plants, such as Phalaenopsis, actually require a period of fluctuating daytime and nighttime temperatures in order to bloom; so if your home is climate controlled and the temperature never fluctuates from day to night, you may have difficulty blooming some varieties of orchids.
Most orchids are robust and able to tolerate being kept at less-than-ideal temperatures. If, for some reason, you temporarily need to keep your orchids at a cooler-than-ideal temperature, make sure to reduce the amount of water you are giving them. Heat-loving orchids will generally be able to weather cooler temperatures as long as they aren’t both wet and cold.
If your orchids that prefer cooler temperatures are forced to endure hot weather, the key is to provide sufficient amounts of water and air circulation. A cool grower exposed to too much heat will bake in stagnant air, but will fare better if there is a fan blowing humid air across its foliage and flowers.
Over time you can investigate the specific needs of each type of orchid you own and eventually fine-tune their growing conditions to meet their unique needs. However, this general advice can help you keep your orchids healthy and happy until you become more experienced.
Beyond their temperature requirements, orchids have specific needs for humidity, light, air movement, growing medium and water. But don’t get overwhelmed; see the Suite101.com Orchid Article Series for all the basics. Orchids are generally very forgiving and it’s not difficult to keep them alive long enough to stumble upon the perfect combination that will reward you with a breathtaking floral display.
If you are an orchid novice, start things off right by purchasing a healthy orchid and a variety of orchid that is easy to grow. Supplement your knowledge with one of the many excellent resources, books and web sites devoted to orchids. The American Orchid Society (AOS) and the collection of orchid articles on Suite101.com are great places to start learning about these amazing plants.