I recently purchased a quality $30 fluorescent light made by GE from the hardware store that came in a box describing the product as specifically for aquarium and garden use. Also in the lighting section were other cheaper and larger fluorescent lights for home/commercial use.
Are all fluorescent lights the same as far as gardening? In my apartment I have plenty of indirect light but this will be the only source of direct light for my plants. I kept the receipt and don't know if I should take it back and do an exchange. I would appreciate your comments/thoughts.
The fixture and ballast (which "turns on" the bulbs) are irrelevant--any will work as well as another, at least in teh short term.
The type of bulb is important. AFAIK, there are three basic types of bulbs: cool white, warm (or soft) white, and wide-spectrum. Wide spectrum is commonly used for plants because each of the others lacks some of the spectrum (cool is more blue but less red, warm is the other way round). You can put one of each of the cheaper bulbs in a two-bulb fixture and compensate, but maybe not to the extent of duplicating the output of two wide-spectrum bulbs.
That's all based on some research I did a long time ago--someone may report a new type of bulb and/or fixture I don't know about.
Keith For more info about the International Society of Arboriculture, please visit
Generally you can use just about any fluorescent light.
You plants will appreciate it if you add some incandescent lights as well to make up for the missing colors of most fluorescent lights. This is less important or not needed at all if you use the more expensive garden or plant type lights.
Using cheap fluorescent fixtures is a waste, the better (electronic ballast type) last longer, don't hum and are more efficient.
If you are going big time, consider mercury vapor types. They are even more efficient and the point about adding some incandescent light still applies.
Different plants need different mixes of lights so experiment. Have fun. It is more art than science.
Mercury vapor? They are expensive, and only about twice as efficient as incandescent lamps, and their spectrum is about as bad as high pressure sodium lamps. You kind of get the worst of both worlds.
Triphosphor fluorescents approach 100 lumens per watt, and they maintain their luminence much better than most discharge lamps.
If you think broad spectrum is important (plants don't seem to think it's important), use GE "Sunshine" fluorescent lamps (available at Wal-Mart, IIRC they come in an orange package), or Philips TL90's.
No, but I do tend to place them all in the same general category. In this case I would tend to leave the sodium out of the running, but I have also seen them used commercially.
I tried a metal halide grow light for a few months. I thought I could overwinter my container plants and save some $$. My light bill went up $40/month, though, so it wasn't much of a bargain. Besides, it made the growing room very hot. I'll try regular fluorescent bulbs this winter.
You'll get different opinions. You may not be able to see a difference between full-spectrum and regular old bulbs. I have seen real scientific-method trials prove it is better, but we all know flourescent is not the same as sunlight. I used the more expensive SUNLITE brand and I have no idea if it made a difference.
I bought a two-bulb unit, but found that I really needed wider coverage. The plants towards the front and back didn't get much light. For the spring I will have 4-bulb units instead.
As to cheap vs. expensive. Manufacturing sometimes makes things so damn expendably cheap that you could buy 3 cheapo units or one expensive. And I'm not sure the one would outlast three.
Energy efficient is important since you may have it on 12-16 hours a day. Otherwise you will see big bills like another poster mentioned.
One item to remember. You'll want to put the unit on a timer, which means you need one with a mechanical on/off switch. Some fixtures will always be off when plugged in--which means the timer can turn it off but never back on.
DiGiTAL ViNYL (no email) Zone 6b/7, Westchester Co, NY, 1 mile off L.I.Sound
Light is expensive. Lumen for lumen, the fluorescents will be more expensive. However in you specific case they may prove to be less expensive overall for a number of reasons. Either should be less expensive than incandescent.
Fluorescent IS mercury vapor, except that the envelope is coated with a phosphorescent pigment. Mercury emission is rich in UV. That wavelength roasts living tissue unless converted to visible spectrum. UV is wasted on plants, anyway, since photosynthesis is most efficient with blue and red bands.
Metal halide uses Hg vapor and a mix of halogen gasses (iodine, sodium, bromine, etc) to conduct the arc. Exact mix is formulated to approximate natural, noon sunlight as closely as possible; televised night baseball games were one of the first applications. Efficiency is excellent, surpassed only by HPS, but more favorable for vegetative growth.
HPS stimulates floral development because its spectrum is close to low angle, autumn sunlight. It was designed for cheap security lighting, where color rendition doesn't matter. Home Depot annual flats are finished under this type of bulb because unknowing customers are more likely to purchase blooming rather than vegetative stage plants, which can better acclimate themselves to their gardens.
Weak bands can be compensated for by adding a couple of the same tubes or bulbs. Old-fashioned T12 fluorescents are cheap enough just to throw in a couple more for insurance.
Use fluorescents if you're strapped for cash. Cool white tubes approximate metal halide. Kitchen-bath tubes can be subbed for HPS.
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