Maximizing yield of 400W - Questions

Discussion in 'Growing Marijuana Indoors' started by nesgames4u, Apr 10, 2006.

  1. So the average I've seen recommended for a 400W HPS, is a space of 4 feet by 4 feet. That's 25 watts per square foot.

    I guess my question is, at about 6 plants - what height would you induce flowering?
  2. Six plants would be ok under the 400 watt even if they get pretty big. Any more than 6 big plants for that light and they will not be lit EFFICIENTLY. As far as I am concerned, those "formulas" are bullshit. Even if your space allows for more than 6 plants under that light according to the formula, you will find out that when they get big and tall, 6 plants is pretty close to the maximum that the hood on the light will allow. By the way, pot will grow with as little as 15 watts per square foot but, I am sure everyone in here will kick and scream and say that this is not so.
  3. Most Id recommend is 4 plants and it goes by type and strain and your Experience what height have you to play with? If your resticted height ways grow an Indica strain..

    These formulas help growers optimise their conditions for the better so well worth adding to favourites so I would advise ALL growers to use them..
    At 15 watt per square foot yeild would be lets say not great poor infact
  4. Interestingly greengrass I plugged in the numbers 4' by 4' @110 volts and here is, cut and pasted, what your web link gave me:

    The area of your grow space is 16 sqft.

    VEGETATIVE GROWTH - 15 watts per sqft
    The amount of HID or fluorescent light you will need for strong vegetative growth, mother plants or cuttings is 240 watts. This will need a power supply with a minimum rating of 4 amps.

    FLOWERING MINIMUM - 30 watts per sqft
    The minimum amount of HID light you will need for flowering is 480 watts, this will need a power supply with a minimum rating of 8 amps. Expert growers can yield 8 ounces per month using this amount of light and space.

    FLOWERING MAXIMUM - 60 watts per sqft
    The maximum amount of HID light you will need for flowering is 960 watts, this will need a power supply with a minimum rating of 16 amps. Expert growers can yield 17 ounces per month using this amount of light and space.

    Note the Vegatative growth @ 15 watts min. Imagine that, check it out. So yes like I said again, 4 plants ideally to 6 plants maximum is what the 400 watt will do. Thanks for the site by the way, it will come in handy when a noobee questions the answer I give to the inevitable light question.
  5. Glad to help someone out be it a noobie or not ...strive for 50 watts per sq feet in FLOWERING and id still recommend 4 plants for that size of grow hope its well ventelated...
  6. yeap,,, i got 5 now under a 400,,, my closet is huge,, so room aint a issue,,,2 of these plants are 3 ft tall[ they look like a christmas tree,,,real bushy,,,] they take up a lot of space[which is the main reason the sog method is preferred by some] i have 1 that is about 9'' tall[my sog experiment plat] i had to put a tall6x6 post under its pot to get it to the right height to get enough light,,, the other 2 are lst, plants they arent that tall,, but they also are sitting on about 18'' tall flower pots flipped upside down,,, basically my first grow is one big experiment,,, they are NOT of the same strain,,VERY IMPORTANT ,i think my next grow will ''definatly'' be the same strain,, and a sog at that,,,i just want to see how this small plants bud is going to do outdoors, bigger is better,, indoors its a little different ballgame,,as the sun rises and sits,the front and back of a plant get light,, inside the light is a straight down shot, shade is a issue,,now a light mover can eliminate that,,,but thats a little high tech for me,, ill keep it simple:wave:
  7. forgot to put a comma in a most importat place,,,,, it should read , outdoors bigger is better, indoors is a whole different ballgame SORRY:eek: :eek:
  8. I have a 400w in a 4x4 tent. I keep kicking myself for not buying a 600w. but things are better than the old T8 shop lights I was using before.

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