Mon February 6, 2012
Garden Report

Supercharge Indoor Seedlings with Light Technology

Now is the time to start seeds indoors, to have them ready for planting outside this spring.  And KUNC Gardener Tom Throgmorton says boosting natural sunlight with technology can help make seedlings stronger.

It’s time to start seeds inside.  Even in our sunny east window the seedlings get spindly and leggy.  With a little technology, we can supplement the sun.

Vegetable and flower plants need the rainbow of colors in sunlight.  Most importantly, young seedlings need the red and blue hues in the spectrum.  Researchers have developed lamps that illuminate both red and blue light...   lamps designed for optimum plant growth.

Typical incandescent lamps radiate the red spectrum of light.  Incandescent grow lamps give off both red and blue wavelengths.  They work well for most plants.  A light table can be built with simple incandescent light fixtures.  Incandescents generate a lot of heat and use a lot of electricity. 

Fluorescent lamps are the easiest way to supplement sunlight.  Specially designed wide-spectrum fluorescents give off ideal light for growing plants.  Less expensive cool-white and warm-white bulbs work well too.  Cool-whites give off the blue light spectrum.  Warm-whites give off the red light spectrum.  We use a light fixture with one each of the warm-white and cool-white lights.      

Fluorescents are easiest to install for the best plant growth.  A fixture can be suspended over a tray or a few trays of germinating seeds.  They don’t even have to be in prime space.  Seedlings can get a healthy start in the basement with the added light.

Distance is a factor with a plant light table.  The lights must be adjustable.  Lights work the best if they’re kept three to four inches above the top of the plants.  A light fixture suspended on a chain above the plants can be moved up and down as needed.  If the light is fixed, build moveable shelves under the light.  As the plants grow, the shelves can be moved down.

If you’re using a plant light table, keep it safe.  This is an environment where electricity and water could mix.  Be sure all electrical connections are protected.  Pull the plants away from the electrical components before watering.  Water carefully to prevent accidents.

A bright, sunny window grows an ok seedling.  An area with supplemental sunlight grows a stocky, healthy seedling.




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