Orchid Culture: Light

Light is energy. Plants are one of few organisms on earth that utilize light to run their production sites, and to create organic compounds. So when you think of lighting for your orchids, think of it as something that is harnessed to create plant material or blossoms.

A plant can be viewed as a living, breathing "factory". When the factory is tiny it doesn't require much energy to function, but as it gets up to scale its energy needs increase. We have noticed that orchid seedlings start off best in lower light, less fertilizer and less water. As they mature they need more and more light. Eventually they need more space. Transplanting them into larger pots with more media allows them to benefit from more light because the "factory" has been given more ground area. With this increase in light they utilize more fertilizer and water in the process.

We have also found that light intensity plays a critical role. Like other plants, many orchids adapt to a particular filtration of light created by their position in the environment. Many climb to higher elevations in trees to gather more light. Most of your typical houseplants grew at the bottom of the jungle floor, so orchids in general need more light than houseplants. Some orchids grow with full sunlight at high altitudes. Imagine the brightness of their natural environment when the fog banks are gone.

The seasons also bring about a change in light, water and fertilizer requirements. During different seasons there are subtle differences in the color of light as it reflects at different angles fraom our solar system. Orchids respond to seasonal changes and its blooming patterns are influenced by the different wavelengths of light, possibly in combination with temperature and moisture. The failure or the proficiency of blooming is many times related to lighting.

When growing orchids in the tropics, we tend to concern ourselves less with manipulating the wavelengths of light than with providing adequate shading. How much shade will produce the best type of growth and when do we need to move the plants into more light? For efficiency sake we move the orchids when we replant. With each upgrade we place them at a higher light level. Or as the orchid gets older, you can test to see if it needs more light. Not all plants benefit from a light intensity upgrade. All plants seem to have their limit, so full blazing midday desert sun is not really recommended, unless it is balanced by cooler temperatures. Temperature is also a form of energy that can affect the orchid factory.

We also find that there are subtle differences in types of dendrobiums and significant differences between generas. Orchidists in the Mainland US often comment that they put their dendrobiums in the brightest location along with their cattleyas. You could even go with 10% more light for most hard-cane dendrobiums. The Latourea section seems to do better under less light than cattleyas. The nobiles seem to grow well under a varied range of light conditions. The grammatophylums also seem to thrive under almost any light condition. Oncidianae seem variable depending on the specific family or varietal type. Sometimes you just need to observe several similar plants in a variety of light levels and see which one works the best. In a few days you could probably tell by the type of growth in the foliage.

Less is more? More is more? With orchids, it just depends on which orchid it is.