2 100W 2700k no exghaust no fan

can this cause a fire ? the temp stay like at 85 degree's

No exhaust will mean no plant growth. The plants cannot grow without air that contains co2. I'm expecting that you'll be using a small cabinet, so the answer is no. You will burn the plants and they wont grow much or any if at all without exhaust. That goes for ANY light. If you can't move air, you have no business putting plants in the ground. Do it right, you could be risking jail for messing around with something that wont work. You mind as well do it right if your going to do it.

how do i do that just put a fan in and leave a hole open?

cAlL mE lOg HeAd said:

how do i do that just put a fan in and leave a hole open?

Click to expand...

Bingo. That'll work.

cant i just open it up a few times a day?

if you are starting out, consider getting some 6700k bulbs first, as they are the best for vegetative! then when you are ready to flower switch over to 2700k bulbs. are you growing in a PC box? 100w replacement bulbs arent as strong as you would think. i am using 3 150w replacement bulbs and 2 of which are 6700k and 1 is 2700k. take a look at my Grow Journal. it shows alot of stuff that i have gone through and between mine and some other guys that post on there you should learn a ton. https://www.rollitup.org/grow-journals/232914-first-grow-using-cfls.html
that being said, you will need a fan as you will see what happened with mine

Also look at this https://www.rollitup.org/cfl-growing/107992-tutorial-growing-cfls.html its the best guide n here for growing with CFL's

hope this helps dude

cAlL mE lOg HeAd said:

cant i just open it up a few times a day?

Click to expand...

no sir. plants need constant fresh air. Just make a hole and blow a fan towards them.