What Kind of Light Do Sprouts Need to Grow?

Blues, Reds and Infrareds

• The green leaves of sprouts, new seedlings, use light energy to produce the food the plant needs to grow. Photosynthesis requires specific wavelengths of light, namely blues and reds. While the plant is still green, these two wavelengths are sufficient to assist in the plant’s growth. When it comes time for the seedling to produce buds and start to bloom, however, the plant will also need infrared light.

Artificial Lighting For Blues and Reds

• Incandescent light bulbs are fine in a room with mature indoor plants. But they are not the best for seedlings since they give off a lot of heat and are inefficient energy users. They also give off light that is mostly red, along with some infrared, but they emit very little light in the blue range. Cool white fluorescent lights produce a blue light, with little red. For new sprouts, white fluorescents are an excellent source of light, producing the blue light necessary for photosynthesis and, without the heat of incandescent bulbs, fluorescent lighting can be placed very close to the seedlings.

Artificial Lighting For Infrareds

• For the development of buds and blooms, infrared light is required. At this point, incandescent bulbs can be used in the growing area at a ratio that gives about 30 watts of red light to 100 watts of the blue fluorescent light. Another solution for providing infrared light is using special plant growing fluorescent lighting. These have a higher red output than standard fluorescent tubes. They are more expensive, so home growers often use them along with standard cool white tubes.

Light Duration

• When growing plants using artificial lighting, make sure the sprouts receive enough light. Plants started from seeds typically require 12 to 14 hours of light every 24 hours. The simplest way to accomplish this is to plug the lamp into a timer.