circular florecent bulbs
 

Can the circular florecent bulbs be used as grow lights. i have some 100 watt and a 138 watt day light bulb. what kind of area will they cover and about how high over the plants do i hang them?

Yes they'll work. The lights should be just a few inches above the seedlings.

Are they full spectrum bulbs? If not you can use 1 warm white and 1 cool white that will give you close to full spectrum.

I agree with sliphorn. No reason they won’t work. When you keep the light only a few inches above the plants, which sliphorn recommends and I agree with, the area covered will only be a few inches more than the size of the bulb itself.

While it would be great if you had full spectrum bulbs or a combination like Dunkel suggests I’m not sure how important that is. I use the standard 48” tubes and buy what ever is on sale when I need them. I don’t even know if they are cool white, warm white or hot white. All I know is they put out light.
:D

My lighting set up is a hodge-podge of wacky floro type bulbs. I have one f18t8 strip in an aquarium light fixture, and two brooder clamp lamps that are designed to use 250w incandescent bulbs. But instead of using incandescents I use the spiral type of floro's that are designed to be used in an incandescent fixture. Both of them are 42w but throw out the same amount of light as a 200w incandescent. So between the 3 I have plenty of light and the seedlings do great.