First Closet Grow! Please help with ventilation!!!

The only thing you can do at this point is fire up that light in the closet for at least a few hours and check the temp with a good thermometer. As long as the closet doesn't get hotter than about 80 degrees, you're fine(ideal temp is 70-80). You'll have to figure out how much to ventilate by opening the door, again, only one way to tell for sure. If your closet is running temps greater than 85, you need to figure out a more agressive plan. Understand that nearly all growth ceases at about 90 degrees.

You should be fine using a portable fan. One 250 watt bulb won't likely heat up your closet too much considering hot air should escape between the top of the door and the header.

80 that's it?
I grown in a small room that is 88 to 90...12/12 from seed.
They love it & grow like crazy! Outside around where I live 100 is nothing.
Lots of water or drip system.

A small closet with no vents running 6 27watt CFLs will get 80 very fast.
But Hydro is King in my closet!

If you're serious about it buy an identical closet door you CAN put some exhaust holes in...then when you go to move out just swap them back. That is, if your landlord doesn't pop in to check on the property at all and wouldn't see this. I'm guessing he doesn't considering that you're even going to do a grow in there in the first place.

You're definitely going to want a fan in there to add airflow onto the plants...it'll help build their strength as well. You can always open it to ventilate every so often, but what if you're caught up at work for a long time? What if you're out of town for a weekend or longer? Not too sure something as big as ventilation should be relying on someone ALWAYS being there. IMO

i ran a 150w hps in a small closet w/o ventilation and couldn't keep my temps below 90. even with fans running constantly and opening the door every few hours.

it ended up being too much of a pain. now i have a t5/cfl setup and it's much easier. i keep the doors closed up all day with a couple of fans running and have no heat problems. i had to give up some lumens with the swap, but it was worth it because plants grow much better when they aren't burning or heat stressed.

so if you can't ventilate i recommend looking into T5s or CFLs.

you are going to have to leave your closet door open if you run a HPS light. It will get to hot in there. You should do with some t-5s, that way you can leave the door shut and open it every couple hours to get fresh air in there. But you are still going to have to deal with the smell. I have an HPS and tried to close my door, raised the temps up real high. Luckly I live in a house so I was able to cut holes in my wall and ceiling on my second grow. Good luck!

Does your closet have a light? If so can you take it out and put a fan in its place. Then when you are done with your grow just put the light back in.

I would go with CFL's or T5's and forget the HID lighting. Maybe when you start flowering you can get a small HPS if nobody is around and you can leave the door open.