In Greenhouses/Outdoors

Greenhouses also have a problem with temperature management – especially in southern latitudes, and in northern latitudes in the summer.  Many greenhouses use a combination of fans and a water-cooling system (kind of like a swamp cooler) to cool their greenhouses.  It also helps to use shade cloth if greenhouses are having a heating problem, as well as even opening up the roof of the greenhouse entirely during the summer!

Additionally, it’s helpful to know the angle of the sun in the sky and the duration of daylength.  You can generate a solar chart for your exact location on Earth by visiting the University of Oregon’s Solar Radiation Monitoring Laboratory.

The most important sign of when to place your plants outdoors is the nighttime low temperature.  You can put Cymbidiums outside when the lows are 40F/4.4C or higher consistently.  For everything else, wait until the nighttime lows are 55F/12.7C or higher to bring them outside.  In the fall, start bringing all plants indoors or in greenhouses when the nighttime low reaches 55F/12.7C for the first time.  It’s better to be more cautious in the fall – frost damage can never be repaired, and may kill the plant.


Temperature is generally not an indoor concern for homes that are climate controlled.  Normal room temperature is always safe to grow any orchid.  However, if you have a “pre-war” home (i.e. older), then your home may experience temperature swings from day to night and season to season.  Additionally, if you live in  a high-rise with large windows, you may experience temperature flux indoors.  Know your space and don’t grow orchids that can’t handle the temperature swings – usually rooms tend to get too hot, so you may not be able to grow cool-loving orchids.  You may elect to construct a cold case (usually a modified wine fridge with a glass door), or grow in a basement – basements are humid underrated places to grow orchids!