I use LED light bulbs from Cree and im covering about 3.5 sq. ft. Going to use them until later this winter, when I build a DIY fixture.
Captain Morgan's thread is where to start for looking at temp bulb setup. Good results.
Something off ebay is ok. A "300'" watt fixture for $89 might not be a bad place to start. It draws about 175+ watts. My problem with these lights is this:
Led guys have set a baseline with white led's that include 25% blue and 30% or more red, with the rest scattered. The leds they are using target good spectrums that people in shitty little labs have found to be "true" about responsive plant growth.
The ebay leds use diodes that aren't the best spectrums, simply put. The best blues are usually set aside to make white led's and sub standard blues and reds are put into the "cheap" Chinese fixtures. They omit just about everything between blue and red, which is a bit. Actual photons that a plant receives is lessened with inferior diodes.
They work, but they are also driven harder, which causes a bit more heat at the diode. You get what you pay for.
I just put up a small starting design for a DIY light in my thread you can build for cheap and everything is snap together no soldering.
Meanwell, Cree CXA 3070 cob's and Bridgelux Vero.
Build it in modules. Build it with whatever colors you like. It is easily adaptable to your space and using about the best LED's on the market currently and still cheaper than most "top=shelf" pre assembled lights
