Dakota Gardener: Grow lights for seed starting

Carrie Knutson
NDSU Extension Agent, Grand Forks County

Spring planting is a few months away and soon many gardeners will be starting their garden seeds indoors.

Starting your own seeds can be a fun activity for your family and allows you to explore different garden vegetables and varieties.

I tried many times to start garden seeds using south-facing windows instead of using artificial lights. Sadly, my seedlings didn’t receive enough light and were tall, thin and floppy. The seedlings did not do well when I transplanted them outside. I learned the hard way that artificial lights are key to starting seeds indoors successfully.

Artificial light needs to mimic sunlight to grow sturdy seedlings.

Sunlight has different wavelengths. Think of the colors in a rainbow. Plants use mostly the red and blue range of light, and seedlings will need the red and blue range of light for strong stems and leaf growth.

Fluorescent and light-emitting diode are common home artificial light options.

Fluorescent lights can be sold as “grow lights,” which provide the red and blue light range. Using cool-white and warm-light fluorescent light tubes is another option. LEDs come in different colors and intensity of light. Blue (cool-colored) and red (warm-colored) are common.

Incandescent lights do not work well for starting seeds. They generate a lot of heat and the light produced is not in the correct light range needed for plant growth.

Seedlings should get about 16 hours of light a day to ensure proper development and prevent floppy plants. An automatic timer is a good idea to help manage the chore of turning the lights on and off at the correct time.

The distance from the seedlings to the light source is another important consideration. Lights should almost be touching seedlings after they germinate. Move the lights up as the seedlings grow, keeping the lights no more than 4 to 6 inches from the plants.

I have a long list of seeds to start this year. Parsley, Savoy cabbage and calibrachoa are a few. My grow lights are busy growing microgreens until the time to start my garden seeds. Happy gardening!

For more information about gardening, contact your local NDSU Extension agent. Find the Extension office for your county in North Dakota at https://www.ag.ndsu.edu/extension/directory/counties.

Artificial light needs to mimic sunlight to grow sturdy seedlings.