How to Choose Grow Lights for Indoor Plants and Seedlings
Authored by Leah Chester-Davis
Grow lights are an important tool when more light is needed for plants. Indoor plants that may not receive enough light from a window, especially during winter months, can benefit and thrive from a grow light. They are often essential for most seed-starting operations. Even a bright window with sunshine streaming in may not be enough light to give seedlings an optimal start. Grow lights can be the solution.
How many types of grow lights are there
Grow lights are available in a wide range of sizes, shapes, types, and price points.
Single bulb
Screws in a regular light fixture or a clamping fixture for a few plants.
Desktop or countertop lights
Best used for herbs, other houseplants or to start a few seedlings.
High intensity hanging lights
Grow lights that can be raised or lowered, or used in shelves on a stack-and-grow system for several plants.
Many grow lights use either fluorescent or light-emitting diode (LED) bulbs.
While fluorescents were once the go-to light source, LED lighting is now the popular choice. LED bulbs typically cost more to buy but cost less to run due to using less electricity than fluorescents. They also do not throw off as much heat. Fluorescents remain popular for many do-it-yourselfers who wish to use long, 2-, 4-, or 8-foot shop lights. T-5 refers to the diameter (5/8 inch) of fluorescent bulbs. They are suitable for growing seedlings but can give off heat so monitor as needed.
Where do grow lights go
Placement depends on the type plant you are growing and the type light you are using. Different light sources put out different quantities of light. For foliage houseplants, a grow light that is placed about 3 feet from the top of the plant may be best. Flowering houseplants like African violets may need the light source to be closer, 10 to 12 inches away. For other flowering plants like orchids, they may need the light source to be even closer. If getting some type of vegetable or ornamental seedlings started, the light needs to be about 4 to 6 inches away.
A grow light that evenly distributes light over the entire growing area is best. If you are growing trays of seedlings, a long light that reaches the entire length is desirable over one that may direct its light to only a part of the tray.
Light intensity is also important. The intensity is greatest the closer the light is to the seedling, and it begins to decrease as you move it farther away. Look for grow lights that have adjustable features so you can raise or lower the position of the lights as needed.
When setting up your grow light, position it 4 to 6 inches above your seedlings. Allow your plants to guide you. If they become tall and spindly, that is a sign the light source needs to be closer. Adjust accordingly. If you see any browning on the plant leaves, the lights may be too close. If the leaves are yellow, that may be a sign there isn’t enough light. Most grow lights come with guidelines on the best distance to place the light from the plant you are growing.
Timeframe for keeping growing lights on and off
Plants need light, typically around 16 to 18 hours a day. The best time to have your lights on is when plants are also receiving natural light or when it is daylight.
Grow lights do not need to be kept on around the clock. Plants benefit from dark periods. Just like humans, they need a rest. Treat your plants like your kids and put them on a schedule for a happier household. A power strip with a built-in timer can be a helpful accessory to make sure the lights are turned on and off on a regular and consistent basis.
