CFLs come in 15, 26, 42, 65, 85 and 105 watts.
The 26s and smaller are like big breasts on a nun, and not good for anything.
26s to 85s do not put out any noticable heat. The 105s put out some heat, but not as much as HID lights.
The 42's are about $9 each.
65 watts are abut $24 to $25 each, 85s are $30 each, 105s are $39 to $42 each, average is $40 each for 105s.
a CFL needs a reflector, like a hood. I like the $10 heavy duty clamp reflectors at Lowes, Home Depot or Walmart. They also offer a cheaper $8 reflector but it is smaller and flimsey.
With CFLs, you need the DUAL SPECTRUM, red and blue. That does not refer to the color of the bulb that you see. It refers to the kind of rays, UVA or UVB, or the color temp, called kevins.
CFLS come in 2700 kevins, 3000, 4100, 5100, and 6500.
2700k is for BLOOM OR FLOWERING , 6500k is the VEG Spectrum. The others are "MID" spectrums or in between.
In outdoors, the sun produces different rays in the spring (VEG Rays called Blue) and late summer for Bloom spectrum, the RED spectrum. (see more below)
CFLs are new on the scene, in 2006 the biggest made was 65 watts. When we talk about CFL watts, we are talking about the actually electricity used, NOT the equivalant. For example, a 15 watt CFL bulb puts out 60 watts.
CLFS PUT OUT LIGHT FROM THE SIDES, NOT THE ENDS OR TIPS.
YOU CAN GET SPIRAL CFLS (15, 26, 42, 65, 85) AND TUBE TYPE CFLS 105s.
How much light is needed for growing?
Depends on the size of plant you are trying to grow. I'll try to answer this "in general" instead of being specific to one size plant. Light seen and perceived with the human eye is measured in Lumens. There is an ideal amount of lumens for growing and a minimum amount of required lumens. The very minimum amount of light required for smaller sized plants grown is around 3000 lumens per square foot. Let me put emphasis on "minimum amount" of light. However, that's not 100% exactly accurate, since although you may have a 10,000 lumen light, the amount of light that reaches the plant varies with the distance between the light and plants, and the reflectivity of the grow area. The ideal amount is somewhere around 7000-10,000 lumens per square foot for average sized plants. As long as the plants do not show burn, as much light can be used as you want to use. (Note, the sun produces about 10,000 lumens per square foot, on a sunny mid summer day).
Determining lumens for your grow area:
First determine the square footage of your area (example in a 4 foot by 4 foot area, there is 16 square feet, 2 by 2 feet is 4 Sq ft. ) If you have a 1000 Watt High Pressure Sodium Light Bulb, that produces approximately 107,000 lumens. Divide this by 16 (your square footage) 107,000 divided by 16 = 6687 lumens per square foot. So just divide the total amount of Lumens, by the total amount of square feet, and that's your lumens per square foot.
