i just built a small growbox (about 3x3x6). i have a 400w HPS bulb. on top of the box i have a 4" 180cfm inline fan exausting air into septic... i have 3 3" passive intake holes on the bottom. i have been testing the temperature and humidity before i begin. the temp get to about 94 degrees. is that too hot to grow in? i've read that you want the temp to be in the 70's or low 80's. i am going to buy a small oscillating fan hoping it will help drop the temp a bit. anything else i can do to drop the temp? i could get one of those glass tubes to go around the HPS bulb but wish i didn't have to go that route. any help appreciated! thanks
Is 80 - 82 to hot. A com grower said to me to keep around 80f. As it is, mine are steady at 77/79 at the mo.
80f is fine. keep in mind guys, that if you supplement extra co2 the plants will be productive in higher temps.
i use: a 2 litre bottle BREWERS yeast sugar mix about half a teaspoon of yeast into the 2 litres of lukewarm water drill a SMALL hole in the cap of the bottle (smaller the better) to allow the Co2 to be released slowly, alternatively you could put a tube coming from the 2 litre bottle going into the bottom of a bowl/bottle of water, this will allow the C02 to be released more slowly. once uv drilled your holes add a cup of sugar and shake a lil bit, remember C02 is heavier than air so you want your bottle to be behind a fan or something so its drawn into the air circulation. hope that helps
The easiest and probably the cheapest way in the long run, to keep your temps optimal... Buy a (portable) or install a refrigerated air conditioner ... unless its a one off grow You can try a million ways to keep your grow area cool but i your air temp is Hot, fans wont cool it, you need cool air, you grow in an enclosed space with 400w it is gonna be way hotter ..
I thought HPS 400w had to be 3ft above your plants? If that is the case you have to consider how your plants WILL be later (in gorwth height) under that light with the space you have. About 75f is good. I think it can be higher if you have a constant water flow as in hydro's because the roots are kept at a exceptable temp with constant flow.