In nature, orchids have humid environments with near-constant air circulation. But, when orchids come indoors, they have to contend with air conditioning, furnaces, or climates that are too dry or cold. So the orchid-grower has to help these plants settle in comfortably by creating conditions similar to their native environments.
If you live on the West Coast, where rising temperatures bring drier conditions, it?s hard to keep a spot humid enough for orchids. They need humidity in the 50-60-percent range. If they have to live with less humidity, they begin to experience stress and start to look unhealthy. However, too much humidity can cause other problems. Really humid conditions of 80-90 percent cause moisture to condense when there?s even a slight temperature drop. This film of moisture is an open invitation for diseases to invade. You can gauge the humidity of an area in your house by using an instrument called a hygrometer. Set it in a room for about 2 hours and then check the reading.
Assuming you?re not growing orchids in a greenhouse, there?s a simple way of keeping a humid area in the house. Kitchens and bathrooms are usually the most humid rooms in the house. If you group some orchids together in one of these settings, they create their own microclimate through transpiration (letting moisture exit through their leaves) and from the moisture in their containers. Gravel trays don?t work, and humidifiers may not be practical.
Most outdoor settings are more humid than indoors. As temperatures rise in the Midwest and Southeast, humidity rises, too. In drier areas, you can add humidity by spraying your orchid and the ground underneath it with water as the day starts to get warm.
In nature, most orchids have nearly constant air circulation. This dries excess moisture and keeps diseases from forming. To keep your orchids healthy, place orchids in such a way that there?s enough space for air to reach all sides of the plants, allowing the leaves to stay cool. Crack open a window or use a fan. If practical, move plants outside in summer, since there?s almost always more air circulation outside than indoors.