I am in search of grow lights for a hydroponic trough I am building. Instead of paying through the nose for a grow light I saw that I have full-spectrum lights and wondered if these will work. My reasoning- the sun emits full-spectrum, so the lights must act like the sun. Am I correct in my guess? I remember picking these bulbs up in the same aisle as all the other ones. They were labelled as “natural light.”
Anyone have any ideas?
Idea #1: look up hydroponics on the Web and see what other people do about this.
Idea #2: It was my understanding that the price is about the same for the two kinds of bulbs. Also, grow bulbs tend to be more available at places like Wal-Mart, while full-spectrum bulbs, especially in 40 watt sizes, are not.
Idea #3: It was my understanding that due to labeling loopholes, what is labeled “natural light” or “daylight” may not necessarily be the same thing as “full spectrum”. It depends on the manufacturer.
Idea #4: It was also my understanding that grow bulbs are only rich in red light, which the human eye perceives as sort of purplish. A full-spectrum bulb, by definition, also has blue light, which plants don’t really need for growth–red light is what does it for them. So you’d actually be paying for something you don’t need.
Idea #5: I personally tend to go through hobbies like other people go through potato chips, and one thing I have learned, through bitter experience, is, “Don’t try to improvise.” If the hydroponics books all say to use one kind of bulb, there’s probably a darn good reason for it.
Idea #6: This is a free country.
Idea #7: It’s your money.
Idea #8: Good luck!
Forgot to say:
Also, the serious shop light has better chains for hanging. The chains on Wal-Mart shoplights really suck, they fall down inside the thing and you can’t get them back out again, plus they’re usually too short to be fully adjustable. For plants, you need to be able to move the lights up and down with maximum range.
I have a two-tier shelf with 18 inch fluorescent fixtures mounted over each tier. I use it for growing African violets and starting tomato plants in the spring.
One tier has a GE F15T8-PL “GRO AND SHO” plant light, and the other tier has a standard “white light” fluorescent bulb. The plants don’t know the difference. The important thing is to make sure you have enough light.
I can second DDG’s suggestion to combine a cool white and a warm white bulb. My wife found this suggestion on a gardening forum for starting plants from seeds. When we were shopping, we compared them with the grow lights at the store. The grow lights were more expensive, and had fewer lumens.
OK DDG, where did YOU get your knowledge? And did it have anything to do with a 24 hour cycle to start, 12/12 to finish? 
One way that I was told to think about lighting was this:
Lumens are more important than spectrum. I used this rule and was quite happy with the results. I mixed 2 cools with 1 warm, focused on the highest lumens per bulb, and everything worked out just fine. I recently went shopping for another aquarium bulb and was surprised to see that the ‘grow’ bulb had HALF the lumens of a normal full spectrum bulb.
So go for lumens, worry about the other stuff later. DDG’s idea about hardware stores, etc is great- I saw awesome light systems for dirt-cheap. One thing you might want to consider is heat- Flours are a good all-around option, especially if heat is a concern, otherwise go for a stronger light system (more heat) that needs a ballast (your hardware guy can explain it further).
But remember- Lumens count! Spectrum is just a nicety.