Vent two different size tents with one fan?

Discussion in 'Grow Room Design/Setup' started by CaliChronIK, Apr 12, 2016.

  1. So I googled this question but didn't come up with an answer specific to my situation. I have two tents, a 4'x2'x5' I plan on using for veg and a 5'x5'x7' I'm going to use for flower. I have an 8" hurricane fan rated at 735 cfm that I plan on using to vent both tents through their respective light hoods.

    As the plan stands now, both tents will be ducted to a plywood box holding an appropriate size carbon filter (Phresh 8"x24" @ 750 cfm), which will be attached the the fan and exhausted outside.

    I have read that this design works, but the smaller tent has at best 6" ducting ports, while the bigger has 8", so my question is will the two different size ductings require me to change anything when it comes to restricting the airflow from the bigger tent, or will the power of the fan be enough to overcome the restriction of the smaller ducting? Both tents will be using passive intakes, and the air will be passing through both hoods.
  2. What kind of lighting are you planning to use for veg? I veg with 4 ft, 4 bulb T5 fixtures...we generally run 2 or 3 at a time, and I don't have any kind of ducting around them or ventilation, etc. If you'll use CFLs for your veg lighting, more than likely you won't need all that. You do understand that each phase of growth (veg and bloom) are done with lighting of different types and spectrums, right? It's typically only the flower lighting that puts off big heat because most people veg with CFLs or LEDs, both of which don't put off massive heat. Most of the time, with those two types of lighting, as long as you keep very good airflow inside the tent around the plants, the fan, ducting and ventilation is unnecessary. Also, the carbon filter you're planning on using will really only be needed in flower. These things have very little smell during the vegetation phase. It's only after they get on into the flower cycle and really start to resin up that the smell becomes a problem. So you probably only need to do the in line fan and ventilation and all on one of the tents...unless you're going to veg with HID lighting. It does put off significant heat and in a small space like you'll be working with, would require some work to remove the heat they emit. We bought the interchangeable cooled hoods that can support hps or hid bulbs, but opted to go with the T5's for veg because they work great for that and don't put off the heat the other bulbs do. Heat will kill your plants quick, so you're right in thinking it all out.

    Just a little FYI for you, but the size and density of your buds is directly proportional to the amount of good strong flower lighting they get during the flower cycle. You don't elaborate on what type lighting you're planning on using, but it's very important if you want to get the best and most out of your plants, that you have enough light to support the number of plants you plan to flower. We flower with 1000 watt hps, 4 per room...about an 8 x 13 ft. area and about 4 or 5 plants is all I can flower under a lamp that size and every plant get all that it needs. You shoot yourself in the foot by overcrowding your light(s) and creating a bunch of shading which inhibits bud development. You can harvest more from one plant that has everything it needs than you can by flowering 4 in the same space. More plants doesn't always mean more at harvest time. So, with your lighting, be realistic about how many plants it will support and don't try to put more under it than that.

    Good luck! Hope all goes well. TWW
  3. Thanks for the reply.

    In the flowering tent I'm using 1000w hps, so I know I definitely going to need ventilation there. I will be flowering 4 plants, SCROG method. As far as veg, I have a 8 bulb, 4 ft fixture I am using right now in a closet, it's about 2 inches too big to fit in the smaller tent. I'm trying to capture the heat in a space where I can efficiently vent it outside, hence my wish to use a tent. I have a 400w air cooled ballast/hood combo that I am considering throwing a CMH bulb in to veg with in the small tent. Summer is approaching, and temps are consistently in the 80's where I live, so I'm trying to keep things as regulated as possible. I do have 200w (actual watt) LED I can throw in there with CFL's to supplement, but I believe ventilation is going to be needed regardless. And of course, both lights will be ran at night.

    Basically, I am trying to avoid any extra costs equipment/electrical-wise, so if the fan I have is sufficient, I would like to stick with it.

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