How Fluorescent Lights Promote Growth and Flowering
While there are some sun-loving plants that grow rather well under a combination of fluorescents and incandescents, you'll notice that it is possible to grow most indoor garden houseplants using fluorescent light alone.
A fluorescent lamp (other than the agricultural types) having the same size as an incandescent lamp gives out two and one half times as much light per watt. The heat output is nearly the same only it is spread over a large area of the tube that it is much less noticeable. That's why we say that fluorescent light is cool.
The area at either end of a fluorescent tube is known as a pole. Light has this property to move in a curved line from these poles. The central 12 inches of tube are the peak of this curvature. This is the portion which lets out the strongest light. This is the place to grow geraniums, cacti, and other succulents, gloxinias, and any plants that favor strong light. Use the end zones for lower-light plants or for spreading cuttings.
White fluorescent lamps give off both red and blue light rays in variable amounts. White fluorescent lamps are sorted as warm white, de luxe cool white, soft white, natural, and daylight. The terms warm and cool pertain to the measure of red coloring in these lamps instead of heat output.
Agricultural lamps like Plant-Lite, Gro-Lux and Plant-Gro use a mixture of red and blue high-energy phosphors. In these lamps the green output has been cut down to increase the energy in the red and blue bands. They go with standard fluorescent fixtures. These lights give off a pinkish-lavender light, giving a totally different appearance to pink and red foliage and flowers. Under these lights the most "washed-out" pink turns vibrant, and the red colors somewhat sizzle with color. So definite is the change in these colors that a lot of aquarium societies include special show sections for fish and plants lighted with these special lamps.
Indeed these are but forerunners of several new types of grow lights which are produced especially for plant growth. Research on radiant energy has resulted in the development of a new phosphor blend which reaches farther into the far red area of the spectrum that produce extra values when employed to high energy crops demanding higher intensities.
"This is good news for, and represents an important contribution to growers of roses, carnations, gardenias, chrysanthemums, and all sun-loving annuals, as well as to such indoor grown vegetables as tomatoes and beans.
These wide spectrum lamp energy sources allow the commercial grower to produce more flowers in a shorter growing season and likewise offer an extra degree of control in timing the fruition of plants to hit holiday markets during the peak.
If you've been growing plants using any setup with white fluorescents and daylight tubes that you have found acceptable, your methods are not outdated. But if you would like to see your garden through rose-colored glasses, or you think your lighted gardens can benefit from a stronger concentration of blue and red rays, then by all means try these agricultural growth lamps.