125w red spec cfl how far away?

Discussion in 'Growing Marijuana Indoors' started by lilvin, Jan 25, 2009.

  1. I am thinkin of getting a 125w red spec CFL for flowering just for one plant. It seems like it would work pretty well. I am planning on not draining my electric bill. I would like to get opinions from people that have used them before. And how far away should I have these above the plant? I have done some researching and it seems like they work pretty well but im not clear on them yet. I also found that if you can comfortably put your hand under it without it burning your hand than thats the correct distance from the plant but im not sure if thats true or not. any information I would appreciate. below is the link for the light.


  2. I'd recommend skipping the big grow light abd buying several 26watt CFL from the hardware store. You can get them in packages of 3 for like 12 bucks, and they put out more light per watt than the big lights. Another advantage is you can keep them spaced aroud the grow for improved side lighting and lower canopy lighting. CFL lights lose their light intensity rapidly so it's recommended you keep them 4 inches from the plant or less. For the cost of that big bulb you can probably buy enough of the small ones to equal the same thing, and have enough money left over for some clamp lights and y splitters.

    If you go with the big bulb you can keep it 4 inches away from the TOP of the plant at all times, but as the plant gets taller, you have to keep moving the light up to keep from burning the plants, and then the bottom canopy will get less and less light. Then you'll have to get some small CFL to supplement the bottom anyway, so why not get a bunch of small CFL at the begining and put them all over the place, right? Plus it's cheaper.

    Try not to worry about a reflector for the bulb either. I've tried different approaches, but some of the best CFL grows I've seen don't use a BULB reflector. Instead, buy the best reflective mylar foil you can and line the entire inside of the box. (It works WAY better than white paint.) Then, just hang your lights all around the plants at different heights around the canopy. Then you don't have to worry about a homemade reflector not reflecting enough light down on the plants- the light will just go everywhere until it gets absorbed by a plant, or hits a wall and bounces back to get absorbed by a plant somewhere else.

    You can still use some lights at the top, but don't buy a big bulb with a reflector- get those clamp on work lights with the spun-aluminum reflector/dish thingy, and hand them from the top. You can even use a couple of Y-splitters in there to use 2 bulbs per clamp light.

    Good luck!
  3. Gotta be honest, I just checked your link, and that light is CHEAP! Congratulations to a fellow ebay buccaneer! That LOOKS like a good deal. I'd be concerned about quality, and the fact that they don't publish how many lumens that light produces. Also, the BIG cfl's run WARM-hot, so remember that too. I've heard complaints about no-name brand CFL's of all sizes burning out prematurely. Even though I use small CFL's, I still ONLY buy GE brand. I guess, try to make an informed decision and go with what makes you happy.

    Just remember if that big bulb burns out:

    1) it could cost you your grow if you can't get a replacement in time
    2) it might not be available that cheaply next time
    3) you'll probably end up rigging up a system with a bunch of small CFL's like I'm describing anyway, just to get you through the emergency
    4) you'll be hating yourself because if you used a bunch of small CFL's, they'd burn out individually, and you could replace them individually, and they're cheap and always available...

    Check out the link in my signature- I go on my soapbox HARD preaching for small CFL useage...
  4. yea def small cfls are the way to go, i went to lowes and bought a 6pk of 24w cfls, for like 6.99$
  5. ok I will just go with a few small cfls instead of one big one. besides I already have 2 daylight 27w 100w cfls and 2 27w-100w softwhite cfls. I will probably use all four for flowering just to even out the spectrum. do you think the 4 27w cfls will be enough for flowering just one plant keeping them under 2" away?

  6. The figure I hear getting kicked around here is 100 watts of fluoro lighting per plant. I have no Idea where this comes from or what logic it's based on, but I stick to the rule of lumens per square footage.

    2,000 lumens/sq foot= Bare minimum for reasonable plant growth
    3,000 lumens/sq foot= way better, especially for flower

    any more than that, the more the merrier, up to a reasonable point...

    Depending on name brand, 4 27W CFL should give you about 6,400 Lumens. Keep the Base of your grow chamber smaller that 2sq foot, or add more lights if it's larger and size cannot be reduced...
  7. I also decided to get 2 42w 150w equiv GE softwhite cfls. Do you think 4" away from the plant would be good or should I put them even closer?

  8. I'd say 4" is acceptable depending on what kind of reflector your using and your air circulation in general. If you're not sure put your hand in between the plants and the lights at the points where they come the closest to each other. Leave your hand there for a minute. If after a minute or so, your hand feels uncomfortable, your plants probably think the same thing. If it feels ok, you're probably alright.

  9. Those are the exact lights I use in my small box, and they work well. I am usually able to get them 2-3" away from the plant without issue. As far as the rest goes, Weasel is right on track.
  10. #10 CFLweasel, Jan 28, 2009
    Last edited by a moderator: Jan 28, 2009

    I originally had 2 of the 42 watters and 2 of the 26 watters... It added up to
    8600 Lumens, which came out to be 600 lumens more than the 150watt monster, and only used 136 watts. I added a couple more bulbs and now I'm getting 12,000 lumens for 188 watts of power used.

    12,000 lumens is plenty for me because my cabinet is only 4 square feet (32"*18" base) which puts me at 3,000 lumen/sq ft. My clone chamber is 1.5 sq ft and has a couple of 26watt blue cfl in there, which comes out to 2,000 lumens per square foot, which is what I read somewhere is the guideline for veg.

    Anyway, I did all the math as far as which lamps were being used for how many hours ( 18/6, 12/12 etc), plus which fans were on during what times and how much power they used. The end result? My cabinet and all the supporting hardware (including my odor control bucket) comes out to be the same as leaving one 150Watt light bulb on all the time. I tried to compensate by replacing all the lights in my place with the smallest CFL's I could get away with, and it's like it's not even there...
  11. is a 40w CFL good enough for 1 seedling
  12. It's plenty. My 1 week old seedlings have been growing fine with just one 24w HO floro tube.
  13. put it this way patna...i have a 125w CFL 6400k over my ladys right now at a week old and its about 2 inches away...i can touch the bulb and its not even that hot..cus there CFLs...

    for my setup i got a 125w CFL 6400k and 4 23w CFL 6500k for 3plants...heres a pic

    ( in the pic its about 4 inches away but then i lowered it and moved a couple of the 23w closer)

  14. I keep my plants about 1-2" away from my fluorescents and never have any heat problems with only a normal house fan as cooling.
  15. I just bought a 200w 6400k cfl. (its the size of a baseball bat but the guy that sold it to me said i would only get one hit) My intentions are to use it soley to flower 2 plants. then they go to a 250 hps. I am worried about the life span of this light. i run it 24/7. Do you think i am better to go to a 20/4 to give the light a rest period or am i ok to just let it run?
  16. running it 24/7 will be fine, but you don't want to flower using a 6400k light. Get a 2700K (or lower K if possible). And don't bother with HID unless you're doing at least 400W.

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