Sorry, I know you probably see topics like this every day from new people. I've looked at several guides for growing weed and I'm 99% sure my grow setup is fine, but I figured the experts should have a look at it. First of all, I don't have $200 to blow on lights right now. Just getting that out of the way, But apparently 4 or 5 CFL's per plant will do the trick. I'm only growing one plant at a time right now so that's fine. So what I have is a square 2x2 box, 2 1/2 feet tall. I know this is small, but I figure a small 6 inch pot will keep the size down. I have 4 cfl bulbs at the top and aluminum foil covering the walls, ceiling and floor to reflect as much light as possible onto the plant. I have a pc fan to bring air in, and a carbon air filter but no fan for the exhaust, I figure as long as the air is going in the intake it will go out the exhaust. I have it in a place where I can monitor the water, air temp and humidity, and the lights are on a timer. I plan to use normal potting soil for the medium. Feel free to correct me if I'm wrong or if there's anything I missed, this is my first time growing.
expect to have temperature issues with the lack of ventilation... i say lack of because 1 computer fan isn't going to move much air. you'd also be better off having the fan exhaust the air and have a passive intake, unless of course you could pick up another fan or 2. i had a similar setup in a 30gal rubbermaid container a few years ago.... ventilation was the biggest problem. i had 4 computer fans and the poor babies would roast if i didn't STILL leave the lid cracked. this was with 8 23w cfls with similar dimensions to your design. in retrospect actually you WILL have heat problems, because aluminum foil isn't very reflective (compared to something like mylar) and it also can create hot spots because it's going to reflect the light and the heat, any crease in the aluminum could create a minor lensing effect that'll torch a spot on your plant like an ant in a magnifying glass. i'm not ragging on your design or your lack of funds to setup shop properly, i was in the same boat 10 years ago. i'm just informing you that a box that size with that type of lighting WILL have heat issues. 4 pc fans was insufficient in my experience with a similar setup.
What wattage CFL are you using? This light is under $70 shipped http://www.amazon.com/Sun-System-900490-Light-Fixt... and would be a good cheap entry light. However your ventilation would need to be altered slightly for this. I'll get to that lower in this post. The aluminum foil isn't going to be all that reflective, if you can get flat white paint that'll actually do you better. A 6" pot is pretty small. Small pot and root size = small plant size more often than not. Solution? Get a bigger pot. You don't have to get a very tall one, but wider will help it bush out a little. Combined with some simple training and you can control the height. Using something like string or pipe cleaners you can tie down branches. Simply drill some holes at the top of the pot holding your soil, tie one end in that hole, tie the other end around the branch. There are people on here who do things similar and I'm sure you could find them if you looked around a little here http://forum.grasscity.com/advanced-growing-techni... or in it's "Plant Training" subforum. Exhaust is more important than intake. At least when talking about a fan doing the work. You want a fan to exhaust the heat. It will also work to bring fresh air into the passive intake. Exhaust out the top of the box (or near top) and have passive intakes near the bottom. This will work better than just an active intake/passive exhaust. If you already have the CFL then try both setups on a dry run and see which has a lower temp. My money is on the active exhaust. However you may need more power with even those CFL, what are your room temps the grow box will be in? If you do the 150 watt HID from above you'd probably need a little stronger fan. However it'd do you better than the 4-5 CFL depending on their power.
I got ninja'd haha. iwearpants is also right about all he said. Hot spots I always used to worry about when people used aluminum foil in their grow. I've read that it is an issue and isn't an issue. But I am pretty sure the easiest solution is to not have to worry about it by using some cheap, flat white paint. Don't need much at all either. I also want to take back my HPS light because of the dimensions. CFL might be better there, but if you could get a slightly taller box then the HPS would be great.
sorry to ninja you, but i'm glad we're on the same page =) also glad the first 2 responses to his post weren't just trolls giving him a hard time.
Thank you both for your input, it has been duly noted. I haven't looked at CFL's yet but if you found something that will produce better light without the extra wiring, I'm all for it. I hadn't thought about CFL's producing much heat, but I guess with 4 of them in such a small space that will happen. I read somewhere to aim for at least 250 watts per square meter, so if my math is right 150 w will work for a 2x2 area. About the light: Apparently HPS lights are better for flowering because of the red/orange spectrum, while metal halide bulbs are better for vegetation because of the blue light. I know it shouldn't start flowering as long as there are 18-20 hours of light, but do you think it would benefit the plant if I painted the walls very light blue to reflect more blue light, at least during vegetative state? If hps light makes it grow vertically, that might be a problem. I was slightly worried about foil reflecting both light and heat; flat white paint is probably a better idea. I will definitely get a better fan or two. I might make the box slightly bigger but the biggest I can get with the location is 30x30 inches, and since the hps light will need to be far enough above it I'll make the box as tall as possible, which is about 4 feet. Since I don't have the ideal amount of height for a hps setup, I will need to keep the plant short correct? And this can be done by tying down branches and getting a short wide pot?
Light is going to create heat. Having ample light in the grow area is going to then require decent ventilation. So CFL or not you'd want more than PC fans. Since that's the case and you haven't gotten the CFL's yet I do think HID is the better route. MH for veg and HPS for flowering like you said. But here are two plants about 50 days old and started under a 400 watt HPS. They don't have that much stretch do they? It'll vary between strains I'm sure, but more because of their genetics than the spectrum. It shouldn't be an issue either since you will probably being doing some low stress training (LST). That LST would be the tying down I mentioned earlier. No reason to paint any certain color. That won't amplify the light reflected compared to white, but it would take out other parts of the spectrum slightly. Flat white paint is the best for paint. Black/white poly film is also good and the next step up in pricing. Mylar is probably the best and going to cost you the most of the three. The differences in your grow would be negligible so white paint would be my recommendation. I would definitely do the taller box. Wider if you so chose to help accommodate the plant and you working with your arms in there. The light I posted above was 15" x 4.5" x 7.5" so far as I can tell. That's not too much room. I think the height is 4.5" but I'm not sure. But between that and the 3" or so you'd hang it at the highest, that still leaves you over 3 feet below. You'd have enough to get a wider pot, some room for the plant, and some room for space between it and the light.
That's what I meant, not actually reflecting more blue light but less of the other colors. But seeing your plants I don't think it will be a problem, especially with LST. Most of the guides I read suggested one or three pc fans for a small personal grow, but you're right more ventilation is definitely better. I think they just suggested pc fans because they'd be easiest to install.
One last thing, the fan I'm looking at will replace the air about twice a minute. Is that enough ventilation? Edit: UTFSE was not applied, I apologize. From what I read exchanging the air twice a minute will be plenty.