I agree with you blueleaf that is true hps are more productive because you get more lumens per watt but I was trying to get at is that with something like a 125w cfl you get about 60-70 lumens per watt but the smallest you get in a hps is 250w with means you are using double the watts ( well a bit under ) to get double the lumens per watt. Don't get me wrong i'm all for cfls but prefere hps. Here is a bit of info for all
HID vs CFLS? Hmmmmmm
HPS definitely produces more denser buds, but, then you have to VENT the HEAT.
and CFLs are cheap.
42 watt average $10.00 each
65 watts, = $19.99 average price ($16.95 now at Lowes and Home Depot)
85 Watt, average $29.00 each, can be found for $24.95 on Internet
105 watt average $34.95 to $38.99 each
Or Look for Clamp Reflectors and Bulbs together:
CFLs come in 15, 26, 42, 65, 85 and 105 watts and recently last year, even larger wattages.
The 26s and smaller are not as efficient to me.
26s to 85s do not put out any noticable heat unless oyu use a lot of them.. The 105s do put out some heat, but not as much as HID lights.
I can touch and hold a burning 65 or 85 watt bulb.
The 42's are about $9 each.
65 watts are abut $24 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 spectrums. That does not refer to the color of the bulb that you see. It refers to the kind of rays, like 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.
IF you sue the MID-range bulbs (4100) then also use the 6500 and 2700s.
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.
Spiral and Tube type CLFS emit 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.
How far away from my plants do the lights go?
The lights in your grow room should be as close as possible to the plants without burning them. There is no such thing as too much light, unless there is overly sufficient heat to dry out and burn the leaves. A good rule is to put your hand under the light, if its too hot for your hand, chances are that the plants will be too hot too, so move the light up until your hand feels more comfortable. For seedlings or sprouts, I keep them a little further away from the light, because they are very susceptible to burning and drying out, at these young stages.
How do I decide which lights to use?
Efficiency is very important when choosing a type of light. The wattage is not the most important thing, different types of light produce different amounts of lumens per watt. For example, a 300 watt incandescent will produce about 5100 lumens. (not that you can grow with incandescent bulbs) While a 300 watt Metal Halide (just an example, they do not come in 300 watts), will produce 27,000 lumens. Obviously far more efficient for growing, while still using the same amount of electricity.