Setting Up Growroom - Ventilation Question

Grown weed outdoors for decades but am undertaking my first full indoor grow, seedlings have been up a few days.

Anyway I'll describe what I have planned and would appreciate it if you could offer opinions as to if my airflow is going to be adequate.


I have set up to grow in my partial basement. It is an all concrete basement 15' by 28' (420 sq feet). I live in the lower midwest US so it stays fairly cool year round, today probably 60F. There is a wooden shelving unit that sticks out perpendicular to one wall and I used it as one "wall" of my for my grow area. My grow area that I partitioned off is 5' X 5' X 8' tall. I have lined the left, rear, and right walls, and the ceiling, with 1/2" insulated "RBoard", and faced it all with mylar. I'm going to probably lay down some plywood on the floor, if after getting the lights fired up it is still too cool.

The front wall, or where you enter the area I am going to make a Panda Film curtain for. Still waiting on the Panda film, but I think the thing will be pretty light tight, but plenty of corners and of course the curtain which will allow some air in.

Ok, lights are one 600W cool tube that I have both MH and HPS bulbs for, and ballast of course. I will also be tossing in some CFLs on the sides the number depending on what the circuit can take. I bought one of those cheap 6" inline booster fans

http://www.amazon.com/gp/product/B003YFADW8/ref=oh_details_o07_s00_i00

which I know is not the greatest but at 240 CFM I thought it would be adequate for this first grow. I plan on setting it up outside the grow area through the left wall (shelving unit). I was going to run the 6" flex duct through the insulated panel, and put the loose end (where it sucks air into) in the right rear corner on the floor, so it only needs to pull air through maybe 12' of ducting.There are enough air leaks around the curtain and other places, so this if how I am planning on exchanging the air. I will exhaust the air into the remainder of the basement. There is one small window I could use if heat, humidity, or odor becomes a problem, as well as a door to a crawl space. I'm hoping to just be able to exchange air with the remainder of the basement, and could use a fan if needed to pull some air down the stairwell. In my situation there is no need for great stealth but if odor becomes a problem I plan on re-doing the exhaust fan to blow out the window or to the crawlspace.

I'm also going to use an oscillating fan to stir the air around. During Veg I'll probably set it up outside the curtain and pull the curtain back and blast air in. During flower I can do that during lights on but will probably need to move it inside when I pull the curtain for darkness. There are a lot of unknowns (temp & humidity)to me until I get the Panda film curtain up and get the lights running.

Anyway that's about it. I also have at my disposal a central A/C duct I can open if the basement gets too warm or humid. I could even run the A/C fan only to get some fresher air in there now, and fresher/cooler air when the A/C season arrives. I also have a dehumidifier.

Does this sound like it might work?

One final question, if you have made it this far. Here is my light and ballast:

http://www.amazon.com/gp/product/B00521B894/ref=oh_details_o09_s00_i00

I currently have it mounted 5' high on the wall inside the grow area. I have read that people often put them on the floor and direct a fan on them. I've only run it for a few minutes but it has a cooling fan and does not seem to generate much heat, I could be wrong on that though. Anyway what are the thoughts on the best place to position the thing.

Thanks in advance for anyone who cares to read through this and offer suggestions. I'd love to hear "that should work fine" but don't sugar coat it if you see a problem

Peace - AIM

130 views and nobody can offer an opinion? I probably wrote this where it does not make much sense to anyone else. Oh well.

Hey buddy. I think you'll need to wait and see what your temp and humidity is doing once you've got your system running. Your cement floor is going to do weird things to your hi and low temps. It seems like you've got all the tools to correct any imbalances! The cool tube will help. Try to have a venting setup you don't need to move at all; aside from cracking open your poly panda film. Put your light dead center over your plants and in reach. Good luck!

I'm not sure how humid your area gets, but I will offer one key point. Do not exhaust back into your cool concrete basement. If conditions prove to be right, you will be setting yourself up for PM (powdery mildew). It will grow on the cool moist concrete walls and then spore out and get into everything. I had that problem in a gro with a friend. Cleaned everything up and exhausted outside and didn't have any more problems. We also used parabolic hoods as it was cool enough all year round that cool tubes weren't needed. I'd make an actual intake on one of your walls imo. I'd be worried about light leaks at the doorway, just my 2 cents. Peace!!

Shaggn said:

I'm not sure how humid your area gets, but I will offer one key point. Do not exhaust back into your cool concrete basement. If conditions prove to be right, you will be setting yourself up for PM (powdery mildew). It will grow on the cool moist concrete walls and then spore out and get into everything. I had that problem in a gro with a friend. Cleaned everything up and exhausted outside and didn't have any more problems. We also used parabolic hoods as it was cool enough all year round that cool tubes weren't needed. I'd make an actual intake on one of your walls imo. I'd be worried about light leaks at the doorway, just my 2 cents. Peace!!

Click to expand...

Never thought about that. I do have a decent dehumidifier that might help and it's a really dry basement. If it came down to it I could vent outside. Venting into the crawlspace does not sound like a good idea to me. As far as light goes it is a storage only partial basement with a water heater and furnace a/c. It only has one small window and is pretty much pitch dark when it is dark outside. So I figured although it may have some light leaks..... there is not much light TO leak in if I schedule my 12/12 dark period during the night. Like mrCRC said kind of hard to predict anything until I get it up and running.

I appreciate both you guy's input.

Oh, and can anyone address my question about the ballast placement and why I would run a fan on it? Thanks