How many CFLS really?

so i have been looking into cfls and i have seen a few tutorials that tell you which type of cfls to use for each life cycle, but no one ever says how many.

is it better to use many low watt cfls or a few high watt?

thats my big question.

i was wondering if i should get 8 23 watt cfls or 4 42 watt, or what.

whats the deal guys??

I have a new grow and I'm using 13 watt for germ/veg. I've got 4 on 1 plants.
I plan to move up in wattage as it gets bigger. More lights mean a higher yield. For a great guide to CFL's check the top section of this forum for the Guide to growing with CFL's or pick up SeemoreBuds book (its also talked about in one of the top threads)

i've read seemorebuds twice and seen all his videos and i have read that really its in the lumens youre using and how much heat in kelvins you have on the plants. i remember reading a plant in veg cycle needs 8,000 to 10,000 per/sq ft. i figure a seedling could use any where from 3,000-4,000 lumens per sq/ft. but i just want to make sure that is correct. right now i'm still waiting for seeds to sprout so i dont have any light on them at all. just finished soaking and put them in peat pellets.

honestly I run both. I have two 65watters two 25watters and one 30watter on my bubba. They say the more watts the brighter the light. And bigger cfl's put out a lot more light. But if you run a bunch of smaller cfl's I think you'd be alright. It's really up to you, what you can afford and what not. I also used a 105w cfl when i vegged but anyways.. I got the big ones on top and the little ones around the side. It's all up to you man. I think 8 23w cfl's would be fine for one or two plants.

The local grocery store by my house is selling 25w 2700k cfl's 2 for $1.00! Lol its a bomb ass deal.

heres my suggestion that has been made to others as well.

get as many darn CFL's as you feel like buying, the more the merrier. Right now I was 5 26W CFL's on one plant and 2 42W and 2 26W on my other plant. Once flowering comes I plan on almost doubling that light. And my plants are only 6 inches tall!

The more CFL's you have surrounding your plants the better!

i have 4 65 watt cfls on one of my plants and it seems to be doing great, remember when you do get your lights make sure you get them as close to yr plant as possible!

This is one of my plants under 4 65w 2700k cfls after 8 days flowering. CFLs work very good.. if you have enough. I would say 2-4 65w per plant.

a chicken in every pot, a cap in every ass, and a cfl for every bud

first try to mount them on there sides way more light comes out the sides not the tip normaly facing down. i would go with 8-10 42watt cfls. with a little mylar i think u would be suprised with what it can do. and co2 will help. u can go bio or all out with a tank and control.

You folks are nuts. More isn't always automatically better.

With CFLs it's all about efficiency. Make use of every photon your bulbs produce. Make sure your box is reflective. Get a good reflector hood for the bulbs. Keep the bulbs close. Train your plants to open them to the light. Don't try to grow monster trees, CFLs are for bonsai bushes and budcicles.

get as many darn CFL's as you feel like buying, the more the merrier. Right now I was 5 26W CFL's on one plant and 2 42W and 2 26W on my other plant. Once flowering comes I plan on almost doubling that light. And my plants are only 6 inches tall!

Click to expand...

Yeah, that's overkll, big time. You're wasting a lot on CFLs and need to just go HID. You're wasting space on all those bulbs, your wasting money buying a bunch of bulbs and your wasting money on electricity to power them.

L I G H T S Page 7


From Ed Rosenthal:

In the new Skunk Magazine there was a question in the "Ask Ed" section that just made my night last night when reading it...



The question was:

I intend to grow a single cannabis plant in a space 1' x 2'. What light would you recommend? I was think of using four 30-watt compact fluorescent lamps. Will this be enough? Cost isn't an issue but I am deterred from getting a high pressure sodium [light] because of the amount of heat the bulb produces.

Answer:

As you mentioned, you have several lighting systems to choose from, including compact fluorescents and high pressure sodium (HPS) lamps. Among HPS lamps you have a choice between a single 100-watt lamp which uses a total of about 120-watts and emits about 8,800 lumens(73 lumens per watt) or a 150-watt lamp, which uses about 180 watts and emits almost double that-15,800 lumens (87 lumens per watt).

A 42-watt compact fluorescent (CFL) emits about 2700 lumens(64 lumens per watt). Four 42 watt CFLs use 168 watts and emit 10,800 lumens. Other size CFLs have a similar efficiency.

However, that is only part of the story. Plants use mostly red and blue light. Yellow and green light is of little use to them, so light that is emitted in these spectrums is wasted energy. Most of the light emitted by HPS lamps is in the yellow spectrum. Only a small amount of the emitted light is is in the orange or red spectrums, which plants use efficiently. Warm white fluorescents (2700 Kelvin) emit a greater portion in the red and orange sectors.
Although fluorescents produce only about 75% of the light per watt that the HPS does, the amount of light usable by the plant is equal or probably higher with the fluorescents. You may wish to experiment to see if adding a single cool white CFL to replace one warm white results in shorter, stouter stems and more vigorous growth. The reasoning is that warm whites don't emit much blue light, which the plants use for photosynthesis and to regulate their growth. The cool white bulb supplies the blue light.

My call for your unit would be to use several (three to five) CFLs with a total input of between 120-160 watts. Although the 150 watt HPS is a bit more efficient that the CFLs in total output, watt for watt the fluorescents provide as much useful light as the HPS lamp. Heat is another consideration. The HPS runs much hotter and emits more heat than the fluoescents.

Make sure to use reflective material around the garden so that any light escaping the garden is reflected back to the plants. Any light that doesn't get to the plant leaves is wasted.


Look at a lumen/watt ration of various CFL's. The higher the wattage of CFLs, the lower the lumen/watt ratio. This chart was submitted by Jerry Garcia, of RIU and edited for typos.

For example...

the 200w listed at 9250 lumens for a lumens/watt ratio of 9250/200=46.25

the 150w is listed at 7500 lumens for a l/w ratio of 7500/150=50

the 125w is listed at 6500 lumens for a l/w ratio of 6500/125=52

the 42w are listed for 2700 lumens, l/w ratio of 2700/42=64.28

I have some 26w that give off 1700 lumens for a l/w ratio of 1700/26=65.38

GE lists some 13w that give off 825 lumens for a l/w ratio of 825/13=63.46

So, according to these numbers the most efficient bulbs for growing are the 26w that emit 1700 lumens. If you used 8 26w bulbs (208 watts total) you'd be getting 13,600 lumens...4,350 more lumens than a single 200 watt cfl.

I suppose you need to purchase more sockets and cords and things to support 8 bulbs, but in the long run more lower watt CFLs seem like the way to go.

imho... if u want to use one 26 watt you can.... if you wanna use a hundred of them, you can... i believe it is all what your grow space allows you to use... my box is 18" tall x 16"wide x 3.5" deep... so with the room i have to work with, i can only fit one 42 watt cfl... slowly with the plants life cycle i have continued to upgrade bulbs and now i am at my max (due to space)... but i never planned on getting anything more than a quarter, so i limited myself, my space, and my plant to my needs... its all about what you want... if someone disagrees, feel free to let me know... i love being corrected (that is the only way i learn new shit)...

You need a bare minimum of 3,000 lumens per sq ft of grow space, to keep a plant alive. 5,000 lumens are a lot more efficient and desirable. 10,000 lumens per sq ft is Max and equal to the sun's rays.
The average CFL produces 65 to 70 lumens per watt. Do the math.