Standard Watts Per Plant

I watched a dvd once where the guy was using roughly 70watts per plant, and the were just fine

 

I'm using two 48' 40watt ott-lites. I have 8 plants sitting under it in line...so far they are doing fine, not too stretched.. I'm going to add some more cfls soon.

 

You can use a lower wattage of light as long as you are covering all the light spectrums for the stage of growth that the plant is in.

 

i would say that 100w is good but its diff. for diff. bulbs (the actual watts used by cfls is low compared to other lights eg. metal halide or HPS)

 

It depends how big you let the plants get. Fluorescents emit a field of good intensity light for only a short distance. For 2 foot plants, 100w each could do the job, but probably not for anything bigger. On the other hand, you can probably flower a pair of clones right from rooting and get away with 1 big 65w bulb. The rule is always more is better, so I say get as much wattage as you can comfortably cram into your grow space without using too much power, getting too hot, or burning the ladies. The great thing about floros is you pick how many watts you use.

 

I read a pretty good book, it says 50 per plant is all you need.

 

How many watts of what per plant?

Different kinds of bulbs give off different amounts of light per watt consumed. Watts is simply a measure of electrical consumption. You cannot generically compare lights based on watts. More specifically, you cannot compare a watt of HID to a watt of CFL (unless you want to compare electicity consumption).

Lumens is the closest available measure of light output, use that for comparison.

 

Lumens are a relative thing as well. Total lumens vs. actual lumens. light diminishes at the rate of distance squared. So the closer the lights are the more lumens your plants actually absorb. HID lighting gives off more total lumens as well as radiant heat (which will damage or stunt the plant). Floros give off less lumens per watt but are much cooler and can be placed much closer (the plants can absorb more lumens with less damage).


If you're going floro get T5 or CFL's with the highest watts you can. 5000K or higher for veg. and 2700K or so for flower. 30W per plant bare minimum.

 

True, lumens still isn't exactly the right measure, that's why I called it the closest available measure. More specifically, lumens attempts to measure the amount of light from a light source at a standard distance, I believe 1 foot. So, since you can get a CFL closer to the plant than a HID, you can get more light from a CFL than the lumens-to-lumens comparison would suggest. But we are talking about how to rate and compare light sources here, so lumens is the best readily available standard -- if someone wants an actual measure of the amount of light being received by the plant they need a light meter.

 

You can grow a plant with a 25w CFL. The 100w per plant is what you need to reach the plants max growth rate and quality potential. It is a factor used for choosing HID lamps not cfls. Not everybody is set up to reach either potential, or even half. You need to look at what is important to you and your grow space.

Example: You are not going to set up a 20'x20' grow room with CFLs. You would not put a HID in a PC tower.

If you need to have max growth rate with the minimum cycle time and still maintain the best quality potential of your plant, then 100 watts of hid light per plant is what is needed.

My opinion on CFLs is; they work great for making clones. If you try to do the whole grow cycle with them, you will fall well short of your plants capability and spend alot of time doing it. That might be just fine with alot of folks.

Peace, R.

 

Exactly, can't say it any better, that's why I use 2 400 HPS, one for each plant.

 

Is 100W per plant a hard number you have some info on? I'm very curious about this as I've heard lower numbers. I've also heard it's somewhere in the neighborhood of 70W per plant if you use CO2 or other growth promoters or things that help the plant deal with heat..

I like the idea of multiple lower wattage HID lights too. This might be a personal opinion but I like the idea of a few 400W lights spread to penetrate light giving the most actual lumens vs. total lumens to a large group of plants instead of one big really intense light.
I'm not talking commercial grows. I mean sometimes you accidentally end up with more than 10 or 15 plants, and I just can't seem to kill them unless they are males.

 

You can't have too much light can you? Cause I'm running a 400w HPS, (4) 48" 40w 2700k T12's, and two 42w 2700k CFLs. I'm not overlighting my single girl am I (she's big enough so that the HPS dosen't lightup the entire plant.

Edit: forgot to include I also have a 2 24" 2700k tubes aswell