You should have a look at the

http://boards.cannabis.com/indoor-li...uch-light.html

thread, which is stickied and answers many/most of these questions.

Lumens are a measure of the power of light as perceived by the human eye. (And before anyone starts to talk about plants "seeing" differently...the human eye is able to perceive light in the wavelengths used to grow.) You can grow a plant with 3000 lumens per square foot, but you're definitely on the low end with that. 5000 lumens per square foot and up is what you want to strive for.

As noted, CFLs don't have much canopy penetration. Distance form the plant is much more important for CFLs. Light from any source decreases in intensity in exponential relation to distance; the amount is the square of the distance form the source. Double any distance from a source and the amount of light will be one quarter of the previous amount. If you've got an HPS light, the 1 1/2" difference between 7" and 8 1/2" won't be huge. With a CFL, the difference of 1 1/2"...going from 1 1/1" from the plant to 3" from the plant...is the difference between getting some buds and getting nothing.

For vegging, you want to find what will be called "daylight" or "full spectrum" bulbs. They should be 5500k to 6500k.

For flowering, you will want to use "warm white" bulbs. These are more common. They are usually 2700k.

Ignore the "watt equivalent." Watts have nothing to do with growing. Watts are a measurement of energy, not light. Lumens aren't perfect, but they're more than accurate enough to determine if you have enough light.