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Thread: 1200 or 1800 watts for a 4X8 grow tent?

  1. #1
    New Member MyOwnClone's Avatar
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    Question 1200 or 1800 watts for a 4X8 grow tent?

    OK, I am setting up for my first indoor grow, have visited 3 local hydro shops, been to 1,000,000 websites, and read Cervante's bible back and forward.

    Typical newbie, yah, I know.

    ANYway, here's the tent I'm starting with for veg and flower - I know it's not top of the line stuff, but I'll be careful with it (4x8x6.5 tall, $189 + shipping and tax): Amazon.com: 100% Reflective Mylar Hydroponics Grow Tent, Non Toxic Hydro Dark Room Box Hut, 96"x48"x78" GYO1011: Patio, Lawn & Garden

    And I am confused about lighting. Really confused.

    Can you help a sister out here?

    Question 1: Should I use 2 x 600 or 3 x 600 MH/HPS lights for 32 square feet? I calculated that they should give me 90,000 lumens each - which gives me either 180,000 (18 plants) or 270,000 lumens (27 plants), right?

    I have some $$ squireled away for my setup and can do the third 600 watt if absolutely necessary... but is 1800 watts overkill for a 32 square foot grow tent?

    Question 2: With either 2 or 3 600 watt lights, in a mylar grow tent, will I need AC? Or should I get air cooled lights? What do you recommend? The grow tent is going into an unfinished concrete basement, I'm in northern CO and the basement stays pretty cool all year long.

    Question 3: I'm deciding between soil or hydro. Does that make a difference with lumens per plant?

    Many many thanks in advance. And, yes, I'm going to do a grow journal, once this gets rolling.

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    New Member Botanical's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    By 4x8 do you mean 8 feet tall? So then the actual floor square footage is 4x4 maybe? If so, 2 lights should do great especially at 600 watts. If it is 4x8 on the floor, then two 600 watt lights should still be good. If you go to three lights you might want to go down to 400 watt bulbs. Check the "how to grow" forums. There is a lot of reading there but if you take the time you will save yourself a lot of trouble. I have a single 250 watt covering a 2x2x6 and it is covered with mylar. I have read the lumens and such is actually overkill for me.

    Cooling? I am wondering what the temp is in the basement. If you set up an exhaust fan that will bring in filtered air from the basement, what temp will it bring the grow room down to if left on for 15 minutes at a time(that's if you get a timer)? Cause if too cold then go for the air cooled light housing. They say 70-85 degrees in the room is perfect or somewhere near that.

    I decided to go for the Hydro gro for easy of nutrient mix and lack of mess. I do believe once in the latter stages of the grow it requires more attention to monitor PH and Nute levels. I think it is A LOT less mess depending on your set up. I am doing the bubble bucket deep water culture and it is pretty simple. I am not sure about lumens per plant though. Mylar pretty much hits the plant at so many angles, the plant will actually get light from all bulbs from like 6 angles or something. I believe the plant will grow with only CFLs and so in my opinion any HID bulb will just kick booty anyhow. Like I said though, read those forums. I wish I had first.

    No matter what, take it slow, note your circumstances and improvements so you will know what happened if something goes wrong.

    Great luck to you!!

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    New Member MyOwnClone's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    It's 4 x 8 on the floor, so 32 square feet grow space all together.

    My basement is pretty much 55 degrees (winter low) to 75 degrees (summer high). It's unheated, concrete foundation, mostly insulated. We have -10 degree days here in CO and 100 degree days, too. It's crazy, our weather.

    I think one thing I want to do is to set up a $20 remote thermometer down there and keep track of the temp.

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    New Member Botanical's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    Hey, I got to reading my "Cannabis Grow Bible Second Edition" and on page 133 it states: "The General Illumination Formula is as follows- you need roughly 50 watts of HPS or MH light per square foot of your grow area. So the formula looks like this:

    250W HID = 2' X 2' area (200W min)
    400W HID = 3' X 3' area (450W min)
    600W HID = 3.5' X 3.5' area (612.5W min)
    1kW HID = 4' X 4' area (800W min)

    So according to my calculations of your 4' X 8' area, you will need 1600 watts. So......you could do that in a few combinations I'm sure. Lumens is the true question though. Some lamps give more lumens than others. Like a 400W could put out 32,000 lumens and another 400W could put out 58,000 lumens. But 2500 lumens is bare minimum per plant and I am sure you will stay way clear of that. Hope that sheds some light on the issue. Would love to see what you decide to do when you got it all set up.

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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    Quote Originally Posted by MyOwnClone View Post
    It's 4 x 8 on the floor, so 32 square feet grow space all together.

    My basement is pretty much 55 degrees (winter low) to 75 degrees (summer high). It's unheated, concrete foundation, mostly insulated. We have -10 degree days here in CO and 100 degree days, too. It's crazy, our weather.

    I think one thing I want to do is to set up a $20 remote thermometer down there and keep track of the temp.
    I would choose neither and go with 2 1000w cooled...it will be cheaper with more light for that space and in a cool basement you might get a way with just cooling the lights. beware of high humidity though while lights off. You can get 30 plants easy and makes no dif. soil or hydro for lighting.

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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    2 600 watters wd. be all ya need for that foot print especially since ya can hold them closer to the plants 1000 wd need to be set high up

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    Resident Connoisseur PitViper's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    If your gonna do it then do it right. 3 600's 600plus cfm fan 6" duct.
    your gonna need a blower no matter what. just get a bigger one.
    I have 1K in 4x4...PERFECT

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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    Yeah I wd. listen to PitViper...

    He knows his stuff...!

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    Resident Connoisseur PitViper's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    another point that I only recently discovered. I also run 1K's on movers with out active air cooling...you can pretty much let them grow into the lamp because the mover does its thing but...
    when I put a blower on a 1K without a mover I have to keep bout 16" away...not because of heat (the housing is cool) but the severe light wash..the intensity on one spot is intense. If you have 7ft of cieling your fine.
    McBudz here has a 4x8 with 2 600's and 1 400 in the middle. he would tell you the same thing.

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    New Member MyOwnClone's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    Decided to go with three 600W lights in my 4 x 8 grow tent and a big ol' fan, just like Pit Viper suggested. If I get an extra 2 oz from having three 600W lights, then that will pay for itself, right?

    Plus - I love the idea of soaking my beautiful plants in light.

    I'm working on finishing out a clone room and a mother room in my basement, under my stairs. Going to put a 400W in the mom room (3 feet by 2-1/2 feet) and line it with mylar. The babies in the clone room get T5s.

    Have the wallboard in the basement, working one lil bit at a time after work - got an Oregon Scientific temp/humidity wireless monitor ($24 at Target) soI can see the conditions all the time.

    Getting excited to get this grow on!

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    Resident Connoisseur PitViper's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    cant wait to see!

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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    U want a base of at least 20 watts a sqare ft. 40 is great. Use CO2 its worth it. Light movers might save you electric. I guess Viper is the one to ask bout them. peace&good luck

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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    Is this show , Soon to be on...?

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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    Quote Originally Posted by PitViper View Post
    If your gonna do it then do it right. 3 600's 600plus cfm fan 6" duct.
    your gonna need a blower no matter what. just get a bigger one.
    I have 1K in 4x4...PERFECT
    Pit,

    what are your thoughts of a 1000 on a mover in the 4x8? will yield suffer?

    Thanks man!!

  15. #15
    Resident Connoisseur PitViper's Avatar
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    Re: 1200 or 1800 watts for a 4X8 grow tent?

    1k gives you 31 watts a sq ft. Ive read that movers increase efficiency by 40% (I dont know if thats realistic but thats what they say) 31w x 1.40 gives you 43w sq/ft.
    I would just hang another 1000.

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