Lighting How many cfl actual watts will i need per auto??

[aussieoak]

Remember plants can only convert x amount of light energy into growth. Anything over 7000 lumens per square foot is not going to mean additional growth.

 

[aussieoak]

Another point, which was eluded to is efficiency per watt or lumens per watt. Yes HPS are better but the gap is narrowed by the simple fact that they must be kept a much greater distance from the plants.

 

[krazylicous]

125 cfl emits 9500 lumens initially

 

[don]

you will want about 50w psft min

if you have 4 very small 1x1 plants thats 200w min

if your going for 1 plant cfl maybe an ok option if you want 4 a 250w hps would be better as it will perform like over 300w cfl

being that your room is so long id put 2 cfl in or a long t5 unit for better light spread

those cfls crack out some heat mind

so 2x 150w ish cfl would be the answer
or 1x 300w t5 bank or 250w ish led

 

[dr_rob_auto]

I'm attempting 2 plants under a 125W blue cfl to veg and a 250W red cfl for flowering and keeping my 15W LED for all the time

 

[riz la green]

Remember plants can only convert x amount of light energy into growth. Anything over 7000 lumens per square foot is not going to mean additional growth.

Where did you get the 7000 lumen's as saturation point from?

The difference to me between 7000 lumens per foot and 10,000 per foot is at least 10 ounces per grow or 33%. It's the difference between a 600w HPS in a 4x4 and a 1000w HPS in a 4x4. 600w light gives 20 ounce and the 1000 gives over 30.

 

[aussieoak]

I did post a few Links in another thread as to where I got my 7000 lumen figure. Search under Posts I have made and you will find it. I actually found around 8 different sites saying 7000 lumens is optimal and also a few Ebooks. If there is a difference from 7000 lumens to 10000 lumens in yield for you it could be that you are not considering distance of light to plant. When you say 10000 lumens that may really only be 7000 lumens at the plant as you can not run HPS type systems right up to a plant as you can a CFL. 7000 lumens is meant to be the most a Plant can use. Any extra is overkill and a waste. Remember it's light at the plant surface not theoretical lumens that the bulb can produce. When you say 10000 lumens if you are using HPS type bulbs that would only be around 8000 lumens at The plant given the distance your reflector Would need to be above the plant. It stands to reason there is a point of feminising returns. Plants only have the chemical capacity to Convert x amount of light into actual growth.

 

[riz la green]

I'm 12 inches away from a 1kw in a parabolic reflector, i'm getting 10k at colas and 3/4 that at branch tops. Some colas are almost touching the rim of the parabolic.

I've read all your posts and what i found from your links was " Optimal is 7000-7500, or higher, lumens per square foot."

Optimal would mean - amount of weed produced per $1 of electricity used.

The most optimal light to own is a 600w HPS. If your space is 4x4 then you would get 21 ounces from a 600w HPS bulb but less and of poorer quality if you would put in 14 130w CFL's totalling 1820 watts. your going to pay 3 times the amount per gram of weed than you would by going HPS.

150w CFL bulb costs £20, 14 = £280, not including wiring them up with extensions and timers.
a 600w with ballast and reflector costs less than £120 with contacter and timer.

I still maintain, the answer to the original question isn't how much light do i need for my grow, it's How much weed do i need from my grow.