4x4 Grow Tent 315w CMH Questions

Discussion in 'Growing Marijuana Indoors' started by Scottyboy567, Mar 24, 2020.

  1. I am currently growing in a 4x4 grow tent with a cheap 1000w King LED that I bought off Amazon. I have had 4 harvests, and am unimpressed with the yeilds (~4-5oz off of 3-4 plants).

    A friend of mine has been telling me to get a Growers Choice 315w CMH. Everything I read about CMH is positive, however I have a couple questions.

    Is this going to be enough light for my tent?
    Should I run the 315w CMH and my current 1000w LED at the same time?
    If not, should i wait until i can buy 2x 315w lights?
    Is this a good fixture to buy?
    Is 3 plants too many for this space with this lighting setup?
    Will a 6" exhaust fan be enough ventilation?

    Cant thank you guys enough for the help!
     
  2. You can definitely use the 315 and the King Led. I would suggest moving the plants around every watering as the plant(s) with King Led will stretch more then the ones under the 315. You want the canopy to remain as even as possible. 2x 315 is awesome for a 4x4, but I don't think you need to wait.

    A bunch of people are going to jump in and say go with QB(s) or LEDs. They are correct, but sometimes you gotta use what you have or can get. The biggest problem with the CMH(s) vs QB is the heat. if you can dump 630watts worth of heat you will be golden.

    you can grow 3 pretty good size plants in a 4x4.
    6" exhaust is fine, if your dumping the heat into another room or something.
     
  3. I wouldn’t bother with the king to be honest, if anything and you really want to use it get a small 2x4 an use the king in there. The CMH315 could use a little blue spectrum but it is optimal for flower. In 4x4 you will have no problem with penetration and coverage but don’t let the plants get too close to it. The reason I suggested using the king in a separate tent would be to veg your plants in there first and then transfer them under the CMH for flower. That’s just what I would do.


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  4. 315w CMH aint enough to do a 4 x 4 justice.

    Id use nothing less than 50w Sq/ft for HID regardless of type, and 40w Sq/ft for LED.

    My Gavita 1700e is made for a 4 x 4, and is 635w of high quality LED.

    Gavita says it replaces a 1000w HID 1:1. Im not saying it, Gavita is.

    1000w Hortilux HPS is 62w sq/ft, and Gavita 1700e is meant to replace this light. Hortilux is 1600umol. Gavita is 1700 umol.
    Gavita DE 1150w is 2100umol, and needs at least 36-40 inches from canopy, or they WILL FRY. Same for any DE HID.
    Of course plants will grow with 315w, but is nowhere near optimal. Not even close.

    We use Gavita 1700e LED, Gavita DE 1150w HID, Hortilux HPS 1000w HID. 1000w CMH... 1150w Gavita/DE CMH will cover 5 x 5. The others cover 4 x 4 optimally.
     
  5. Hortilux says 3x3. I have found them to be correct. I tried to push to 4x4 and the outside plants would stretch. I totally rec u run hortilux bulbs if that ballast will fire it up. Maybe inside a tent might make a difference to 4x4 20200311_181705.jpg 20200321_073146.jpg

    Sent from my SM-N960U using Grasscity Forum mobile app
     
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