Most incandescent plant lights are best used to highlight indoor plant groupings and have very little use as a true plant 'growing' light, even those that are labeled as a "grow light". Newer color corrected incandescent spot grow bulbs are suitable for adding supplemental light or highlighting to a single plant, such as an orchid or indoor bonsai tree. On a cautionary note, you should never place an incandescent bulb closer than 24 inches above your plants. Incandescents burn very hot and will burn plants when placed close enough for them to appreciably affect plant growth. Most incandescent bulbs have a relatively short average life span of 750 hours. Fluorescent Plant Grow Lights Recent advances in fluorescent technologies provide the indoor gardener with a multitude of options. Not only can you start your seeds with fluorescent lighting, with new high-output and compact fluorescent technology, you can grow full size plants that produce full-sized fruit and flowers.
(T-12 & T-8) are still an excellent choice for starting seedlings to get a jump start on spring plantings. They also are excellent for cultivating a cool weather harvest of leafy greens in the basement year round. Leaf lettuce, spinach, and herbs all will do well year round under fluorescent lamps. The trick to using them successfully is to keep standard fluorescent bulbs no further than 4 inches away from the tops of the plants. Since the tubes burn relatively cool to the touch, you do not have to worry about burning plants unless they are actually touching the bulb. Fluorescent tubes are an excellent choice for the display and grow lighting of African violets, small cacti and succulents, and many kitchen herbs. New advances in color blending make full-spectrum standard fluorescent tubes one of the truest color rendering lamps on the market today. Standard fluorescent tubes are more efficient than incandescent bulbs, producing twice as many lumens per watt of energy consumed with an extremely economical usable life span of up to 20,000 hours... more than 25 times as long as an incandescent.
High Output T5 Fluorescents
produce almost twice as much light as standard fluorescents while still burning very cool to the touch. HO fluorescent fixtures have a very thin profile, around 3 inches in most cases, making them extremely useful in vertically limited areas. Most can be hung vertically on a wall for side lighting as well. High Output T5 Fluorescents produce about 5,000 lumens per 54 watt, 48-inch bulb and are available in warm (2700K) or cool (6400-10,000K) versions. Average usable life span for High Output Fluorescent tubes is about 10,000 hours. Like standard fluorescent fixtures, High Output fluorescent fixtures are available in both two and four-foot lengths. Unlike standard fluorescent fixtures, High Output fixtures are available in 2, 4, 6, and 8 tube models. An eight-tube four-foot High Output fluorescent fixture produces as much light as a 400 watt metal halide lamp (40,000 initial lumens), but spreads that light much more evenly over the growing area. Most High Output fluorescent fixtures can be hung vertically against a wall for very effective side lighting applications.
take the cool burning fluorescent technology and pack it into a focused, high output "bulb", that you can use not only for propagation, but for growing larger plants as well. Compact fluorescents work in specially designed reflectors that efficiently direct light to the plants, much like the high intensity discharge lamps described below. Compact fluorescent bulbs are also available in warm (2700K) or cool (6400-10,000K) versions. Average usable life span for Compact Fluorescent bulbs is about 10,000 hours.