The right light condition is one of the most important factors for successfully growing orchids. When I talk about the right light this includes two aspects. One is the light level, the other is the duration the light is available every day. If you get either wrong, your orchids will grow poorly and probably won't bloom.
Light level
Each orchid has a preferred light level, some like low light and shade, while others desire full sunlight and the highest possible light intensity. If an orchid is kept at a light level that is too low it will grow slow and the leaves will stay small and may even be deformed. The plant will also be weakened and prone to all kinds of pests. And most importantly it most probably will not bloom. A good indication that the light level is too low for your orchid are leaves that are dark green and new leaves that are smaller than the leaves when you bought the plant.
Too much light can be dangerous as well. While many orchids like plenty of light, beware of too much direct sunshine. As it can cause sunburn of your skin, it can also cause sunburn on leafs. And more light means that the orchids heat up and use more water, the danger is that they dry out. A good indication for too high light levels are light green to yellowish, bleached leaves, in many cases with a reddish rim. Phalaenopsis also tend to develop black spots.
Light duration
Not only the level of light, but also the duration is important. For many orchids, the change from short days in the winter to longer days in the spring, together with the change in temperature, initiates the blooming. Some orchids that prefer intermediate light levels might be ok with some direct sunshine, as long as it does not exceed 2-4 hours per day. For others, that love the shade, a single hour of sunshine might be too much.
How to measure the light level
Our eyes are a very improper tool to determine the light level. They automatically adjust to the brightness and try to give you an even impression of your surroundings. But there are some general rules: South facing windows are brighter than east or west facing windows. The lowest light levels are in north facing windows. And the closer to the window, the higher the light level will be. And beware of windows that are heavily shaded by trees, in many cases these are not suitable to grow orchids.
The best thing is to measure the light level with a light meter (also known as lux meter). I prefer the digital version, which gives you a reading in either “lux” or “foot-candles”. After a lot of research I have found the manufacturer of an inexpensive, but reliable digital light meter and now offer it in my shop on this web site. |