Light is important for plant growth. Without it, there is no photosynthesis, and plants cannot grow and thrive. Light is often the most limiting growth factor when growing houseplants, starting seeds, or nurturing any plant indoors.
In the home, even the brightest windowsill only has a fraction of the light intensity of any outdoor location. Light levels are particularly low in the winter because of the short days, low angle of the sun, and often overcast weather. While houseplants differ in their lighting requirements, many benefit from supplemental lighting either during the winter or year-round.
Below is a guide to providing supplemental light for houseplants, seedlings, and other indoor plants.
These three factors are used to determine the light requirement needed for best growth, called the daily light integral (DLI). This is one of the most important measurements for growing plants under lights.
Learn more about the important factors that need to be considered and how to calculate the DLI in this article: Important Considerations for Providing Supplemental Light to Indoor Plants.
Many different types of fixtures are available to provide light for houseplants, seedlings, or other indoor plants.
The supplemental light sources available to home gardeners include LED, fluorescent, and others. Which you select depends on several factors as each light source has advantages and disadvantages.
Factors to consider include light intensity (amount), wavelength emitted, cost to purchase, efficiency, and the amount of heat produced.
Learn more about selecting the best source of supplemental light for indoor plants in this article: Sources for Supplemental Light for Indoor Plants.
Once you've determined how much light your plants need (a target daily light integral or DLI) and what type of fixtures you wish to use (LED, fluorescent, etc.), you can build a supplemental light setup perfectly suited to provide the best light for your indoor plants.
Information on how to determine the number of fixtures that will be needed, what factors to consider when building your setup, and example setups you can use at home can be found in this article: How to Set Up Supplemental Lights for Indoor Plants.