how hot is too hot

get on all, i have a cupboard grow going and try as i mite i cannot get the day time temp down below 90 it stays a steady 90 though, my only option really is to raise the light right up, so i would sacrifice lumens for the sake of being slightly cooler, the dimensions of cupboard are 4 foot by 1.5 foot and 7 foot tall and i have a 400w mh bulb in there as plants are veging, please advise as it may well be i would have enough light for themm even right at the top cheeeeers in advance

Anything higher than 85°F will stunt growth
You need a real exhaust fan to pull the hot air out of the cupboard

put a fan on them,this will make the plants stronger , also put an exhust fan to get the hot air out .

thanks tom and cutman, i had an oscilating fan internally but have now fixed a bathroom extractor in cupboard aswell and temp is holding a steady 81 degrees in day and 68 degrees during 6 hour dark period, cheeeeeers to you both.

sounds like you got it set up working good now fall guy, good luck with your grow bro

Supreme Skunk said:

sounds like you got it set up working good now fall guy, good luck with your grow bro

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Cheers buddy im going to start a grow journal today so you guys and gals can check out the setup and see if theres any improvements to make........cheeeeeers

the fall guy said:

Cheers buddy im going to start a grow journal today so you guys and gals can check out the setup and see if theres any improvements to make........cheeeeeers

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Or you could use a cool-tube connected to a smallish carbon filter, 1 in side the room connected via ducting to a cool tube,with an in line fan sucking the filtered air out, and then run ducting out into your main room with a 2nd filter attached to that end, the exhaust will not smell, it'll heat you house nicely but not dominetly, and most importantly decrease the heat build up which will otherwise stunt their growth and they'll most prob.die you ll need either a small fan intake or a passive filtered intake, but this along with fan speed switch will give you optimum control of your enviroment, hope this helps STELTHY

my 2x7x7 closet was way too hot with my 1k light. i solved the problem with a sealed air-cooled reflecter. it was reaching tepms over 100f and now hovers around mid 70s. i keep my inline fan used to cool the reflecter on constantly during the day. i use a duct booster 15min every 2hrs to vent the room.