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Getting Started - Lights! Action!
The natural light from a window is seldom enough for good, strong seedling growth. They will usually stretch and lean towards the light and will not produce sturdy plants.Sowing seeds indoors under fluorescent lights is the easiest way for the home gardener to control growing conditions and grow healthy transplants. Incandescent bulbs give off more heat and less light (mostly red) than fluorescent tubes and will not produce good transplants by themselves.
Many gardeners use inexpensive and widely available “shop lights”- 4-ft. long lightweight metal fluorescent fixtures that take two T-12 fluorescent tubes (multiply the T-number X 1/8 inches to get tube diameter; in this case 12/8 or 1 ½ inches). You can easily hang these fixtures by removing the strip or panel above the tubes and inserting chain or wire through the hole(s) in the top of the fixture.
Click the photo below to view photo gallery of “light stands” sent by GIEI gardeners.
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Light Stand Set Up Options- Photo Gallery |
Cool, white tubes (40 watts) produce light in the blue and yellow-green segments of the light spectrum. They are the least expensive and fine for growing transplants. More expensive full-spectrum fluorescent tubes (“grow lights”) are available that produce a balance of warm (red) and cool (blue) light. These enhance plant growth and are useful if you are growing transplants in your basement with limited natural light. Some gardeners use one cool white tube and one “growlight” tube for each shoplight.
Another option are the newer T-5 fluorescent fixtures and tubes. They are relatively expensive ($150-$200 for fixtures and $15 for tubes), but they more energy efficient than T-12 set-ups and produce excellent plants. The T-5 tubes can’t be used in a T-12 fixture (common shop light).
The following is an article by Edward J. Leonard, M.D., a UME Master Gardener who took the leap to T-5s:
Growing seedlings indoors with T-5 fluorescent tubes
My wife, Ann, is the gardener in our family. Like the queen bee, which begins her egg laying in February, Ann has already ordered seeds for Spring planting. As Master Electrician and trouble-shooter, my role is to be sure that that the banks of 48” fluorescent lights in our home-made light table are functioning. Ann plants seeds in Gardener’s Supply self-watering trays, which can be positioned under the lights. Last year, after reading that chlorophyll light absorption has two peaks at opposite ends of the visible light spectrum and that photosynthesis rate had a similar pattern [see figure], 
I purchased a new lighting fixture. It’s a 48” unit, which accommodates 6 fluorescent 5/8” diameter T5 lamps, tucked up under a highly reflective surface. These lamps are made with 2 different light outputs, at opposite ends of the visible light spectrum, one red and the other blue-violet. Since the two absorption maxima and synthetic activity of chlorophyll are in just these regions, I installed 3 of each type of T5 lamp, for a total light output of about 24,000 lumens. In contrast, an array of 3 of those familiar fluorescent shop lights have total emission of about 7,500 lumens in a region of the spectrum with minimal chlorophyll absorption.
If you are familiar with the spindly seedlings grown under shop lights, you will be amazed at the results shown below. These hybrid tomato seeds are programmed for vigorous vegetative growth, producing sturdy plants under the T5 lights in 5 weeks and rewarding us with tomato clusters within a month after transplanting.
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Last updated: 03/2/2011