Temperature?

I have an insulated grow room with a 400 watt HPS bulb. The room is usually 80-90 degrees when the light is off, and 100+ when it is on. I put a fan in the room, and ventilation holes, but the temperature is still 100+. Will this kill my plants? Will it set my room on fire?

it may kills your plants... i dont think it will set it on fire unless your bulb is touching paper or something... it will effect yield and stuff too.. you need a cooltube, inline fan and filter and then you can vent properly.

your better to shut that 450 watt off, and trying a florescent, the plants wont dye at 100f but over that it will stunt growth no strength thc, pis pore buds and plants. the plant will go into survival mode, does not care if it flowers or not. get them temps a min of 90 late flower, wont be any thing special still. but a lot better , order it goes . clone temp 65 to 70 . veg temp 70 to 90. early flower 75 to 95. depending on co2 ppm. later flower. 65. f tight buds.

You need an exhaust fan to suck hot air out of the room. The exhaust should be near the top of the room as this is where the hot air collects.

You should also have an intake roughly twice the size of the exhaust located near the floor. The pressure created by the exhaust will draw air in through this intake without the need for a specific fan.