400w Cooling Question

I'm growing 3 plants in the corner of a tool shed. The walls are mylar lined and there is a window. The temp high is 76 with a fan going( 82 without). If I run a switchable 400w HPS/MH and I can keep the temp down, do I have to run ducting and a cooling fan to the light?

No need. 76 is great. Just try to keep your low around 70 if you can.

Thanks. That's what I thought. The hydro shop guys are trying to talk me into a full set-up. I'm just going to go with the all-in-one switchable that has a built-in ballast. I got that quoted at $216 including both bulbs. I can always upgrade to the better quality lamps at a later time.

build in ballast can create quite a bit of heat.

using a cooltube or any other air cooled hood will let you get the light closer to the plants and thus maximize its effectivness. You could vent it out or just use a small vent and keep the heat in the room.

However, you still want some air exchange in the room - thats a very important issue. Its not about cooling the light, its about giving the plants fresh air and make them move a bit regularly.

If your temps stay that low you won't need to worry about serious ventilation. You'll still need some fresh air exchange in there for the plants though. A cracked door with an oscilating fan in there would do the trick. It would be the easiest, anyway.

I will be running oscilating fan and there will be a window open. The light and fan will be on a timer and I made a light proof shroud for the window to keep light out. I'm only trying to grow 3 medium sized plants without going full out with the set-up.