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

[Egzoset]

Salutations Stunted,

I wish you to be reassured, knowing that i didn't feel directly concerned. Well, i do wonder but anyway i'm willing to try 6 x 45 Watts (3000 lumens x 6 = 18000 lumens) over an area occupying about 32 square inches. I should know how it works by Christmass since 2 of my 4 AutoMaria II are already 60 days old... I'd also like to have light on the sides but this will have to wait a bit.

...and thanks for the good waves!

 

[aussieoak]

Hi all this is my first post. I love this forum and the potential for auto strain grows with all the new strains out there. Many years ago I grew photo period plants under MH and HPS using a constant flow system in Clay balls. Got good results. In recent years I have only been doing outdoor grows. I fit three grows of autos into this summer while I am still growing out my photo plants. Have been thinking this year I will go back to some indoor grows. I have decided to use cfl's and soil/vermic/pearl mix. That way I can germinate and grow in the same pot. Will just use some bloom nutrients during flowering and some organic general fertilizer during veg, something like a fish/seaweed mix. Will add some pony poo ect to soil mix to make it all nice and organic. The lights I will use will be 130 watt cfl's which produce around 8000 lumens each. Finally to the point of this post, most of the sites I can find suggest 7000 lumens per square foot is optimal which is much more than most contributors to this thread have suggested. See links.

http://www.weedguru.com/forum/viewtopic.php?t=28014
http://buymarijuanaseeds.com/community/threads/lumens-and-wattage-per-square-foot.55584/

Please feel free to correct me but in setting up my room this year in will aim for 7000 lumens per square foot.

 

[Eekman]

Here is my opinion.

If you have a grow box that is 3x2 and 6 feet high. Your plants are only going to cover 2/3 of your box (estimate). So you only need 2/3 of the square footage of your box.

2 x (3 x 6)= 36 x .666% (2/3) = 24 square foot of coverage. (24 x 75 = 1800)

I guess what I am saying is, don't count the box, count the living area of the plants.

Just the way my mind skews it

Eek

 

[aussieoak]

True I guess but for ease most just base their calculations on the room size. Sometimes lateral reach into every nook and cranny of a room so it's best to have full light cover. Anyhow based on a small 4x4 room, which is 16 square feet I would need around 16x7000=112,000 lumens for the room. A 130 watt CFL giving 8000 means I will need 14 of them to do the job. Starting to make them not look so attractive. Comments ?

 

[toke]

lots of good CFL info here aussie should help
T5/CFL only thread (the manual)

TOKE OUT

 

[krazylicous]

lumens; a 23w compact fluorescent emits about 1600 lumens.


if a 23w cfl is producing 1600 lumens does that mean that my cfl 125w is producing around 8000 lumens ?

 

[InHumboldt]

One of the basic rules of thumb in floresence growing (any kind of plant) is that above about 40w per square foot it takes a lot more power to get a small increase in growth-from down low up to 40w/ft' one gets a lot more growth for small increases in power.
Also the basic lumin per watt is 2/3w x 100= lumens. @40w/ft' So 2666 lumens per square foot would be a starting point for overdrive the lumens------but just like 350 horse power in a car will pull it away from the light quicker-- but the cost in gas ????

 

[riz la green]

When i started out i read that i should have at least 3000lm per square foot. However, the bonus of CFL is that you can rig up as many in the box as you can cope with the heat from and you can arrange them so they hang down beside and between the branches of your plants since they don't get very hot the plants can be 1 inch away from the bulbs.

FYI i have a 4x4 tent with a 1kw HPS - 150000lm - almost 10k lm per sq foot
and a 3x3 tent with a 600w HPS - 100000lm - just over 10k lm per sq foot.

I do get a little light bleaching. if your looking for efficiency, the 600w HPS gives the most lumens per watt that you can get (not counting new LEDS)

 

[riz la green]

A different approach to your question is " how much weed do i want to get from this grow?"

Take the benchmark bulb - 600w HPS, as long as you make no mistakes and plant enough plants in big enough pots your likely to get 21 ounce from a 600w light which is 600 grams. 1 gram per watt. Thats the standard that a lot of growers aim for.

CFL are not as efficient, say about 40% as efficient. Aim for 2 ounces from your grow, so 28 x 2 - 56 grams, since CFL's aint as strong and you need about 125 watts. Since your new and will make mistakes that effect yield, add on an extra third of the 125 = roughly 40 gives you 165 watts to get 56 grams of weed.

Now you know you need 165 watts of light for 2 ounces, you can either grow lots of small plants in small pots creating a mini sea of green or you can go for one plant in a big pot.

Obviously adjust the figures as needed, hope that makes sense

 

[aussieoak]

I found a shop in Australia that sells 130 watt cfl bulbs for $59 each and are rated at 12000 lumens. It does not matter what you use it all comes down to lumens. A clf can produce just as much dope weight if the lumens are there. Sure they are not as efficient per watt but I intend to use the 7000 lumens per square foot rule which means for a 4x4 area I will need around 9 bulbs. I know that is a lot more watts than would be used by a HPS but its heat that is my main concern not power. If I go with 5000 lumens per square foot, which I am told will also work well, I only need around 6x130 watt bulbs to have plenty of light which is only approx 800 watts but Means bulbs can be real Close to plants and room is cooler. Also given bulbs can be Closer to plants less light is lost. With HPS and MV or MH as lot of light is lost keeping bulbs a safe distance from plants. Comments ?