Lighting New lighting for my grow box

[Autoflowerpower420]

Hey guys!

I have a box that is 4 feet tall and 2 feet wide, I have a total of about 200 cfm worth of intake and exhaust fans and then a 10 inch fan in there as well. With 8 cfl bulbs going it gets a little hot up to 87 at times if I keep the closet door closed for long periods of time, but then again the lights are about 8 inches from the plant and I'm not too sure how accurate my readings are. If I got a 600 watt Mh/hps bulb and put it on the ceiling of the grow box which would be a total of about 2 1/2-2 feet about the plant would it be too hot in the box? I don't know how hot those run but I know they do run pretty hot. So IF that would be too hot, should I go with a 600 watt and a 6 inch inline fan right across from the bulb or just a 400 watt same distance from plant with my current fan setup?

 

[Tairy Greene]

What's the square footage? 2ft wide but how long? A 600w should cover 3'x3' to 4'x4'. They do put off some heat but if you can air cool the bulb and exhaust out of the room you should be fine. Keep the 600w 12-18" away from the tops.

 

[Son of Hobbes]

Hey guys!

I have a box that is 4 feet tall and 2 feet wide, I have a total of about 200 cfm worth of intake and exhaust fans and then a 10 inch fan in there as well. With 8 cfl bulbs going it gets a little hot up to 87 at times if I keep the closet door closed for long periods of time, but then again the lights are about 8 inches from the plant and I'm not too sure how accurate my readings are. If I got a 600 watt Mh/hps bulb and put it on the ceiling of the grow box which would be a total of about 2 1/2-2 feet about the plant would it be too hot in the box? I don't know how hot those run but I know they do run pretty hot. So IF that would be too hot, should I go with a 600 watt and a 6 inch inline fan right across from the bulb or just a 400 watt same distance from plant with my current fan setup?

Wouldn't suggest that size of HPS/MH for that small of space. What's the length of your cab? For starters, you aren't working with a lot of height for that size of light. Most recommendations for space between the top of the plants and the HPS light are between 18 inches and 24 inches (and sometimes higher, depending on certain conditions.) At 4 feet, or 48 inches, after factoring in the space between the light and plant, you're looking at maybe 24 to 30 inches of usable space. Here's the next snag, an open air reflector HPS would COOK that space in no time. You'd most likely want to look into a vented hood or a cool tube, which is going to eat up at least another 6" in vertical space from the fixture, and that's assuming it stays fixated at the roof of your cab. So now that 24 to 30 inches of usable space is now about 18 to 24 inches of usable space.

What size pots are you using? Now factor in the area the pots take up. Don't forget the space that ductwork takes up!

I'm not trying to discourage you; I use HPS/MH myself and have dealt with a plethora of heat/space issues.

Any chance you could throw up a few pictures of your cab so we can see what you've got going on? Might be able to make a better recommendation once we see what you've got going on. A dimmable ballast may be a good option for you; they are becoming pretty common on most 400/600/1000W digital ballasts, and often allow you to dim the light back by 75% and 50%, which in turn will reduce the amount of heat generated (at the expense of lower power.) Is there a reason you're sold on the HPS idea? Ever consider LED lighting? May be a good option for the size of your setup! We have some great LED growing guru's on here; would be more than happy to direct you to one of them if that's something you'd consider.

Let us know bro; we'll this all sorted right quick and find the best solution for your setup! :Sharing One:

 

[Autoflowerpower420]

Okay the entire box is 4 feet tall, each side is 2 feet wide. It's a rectangular prism.

 

[Autoflowerpower420]

Another question! I figured I would get a 400 watt Apollo horticulture kit with the extra bulbs and timer and hangers ect. And Say I was gonna get a 6 inch inline fan. But in order to get the 440cfm wouldn't I need a 6 inch intake as well as 6 inch exhaust?

 

[Tairy Greene]

I assume you are exhausting out of the room through the hood and have a passive intake. If your hood is 6" air cooled, you will need 6" intake and exhaust. To optimize you want 3x the intake as exhaust. You can get away with less tho. 2-6" passive intake ports can suffice.

 

[Autoflowerpower420]

I don't think I'm getting a cooling tube so I would only need an intake and exhaust?

 

[Mr Piggy]

If you have a six inch fan on outtake with a carbon filter on it and a six inch fan on intake with no restriction you will create positive air pressure in your grow box and it will push the smell out instead of filtering.

A six inch fan on outtake with a carbon filter should be fine for ventilating a 400w HPS in a grow box, but there's a few issues.

A 400W Hps will turn a little 2x2x4' grow box into an easy bake over. The 400w light needs head space above the plants of about 18" take the pot space of 12 inches off of that and you're left with about 16" of actual growing space. Not optimal for your space.
I would either stick with the CFL lights or go with a 250W HPS which is perfect for that space. Given the low head room LED might be your best option, but they require a bit of initial investment. with cfl, a 250w hps or LED you will have no problems using a four inch fan and smaller filter in there.

Lastly, you cannot grow in the closet with the door closed. Plants need fresh air just like we do. With the door closed your temps will be hellish as well. Either the door needs to be left open or you need a new spot.

Hope that helps!