Max temps for grow space?

TedeBoy

Well-Known Member
What is the highest for temperatures in a grow space and still produce good plants?
I got a 315 LEC and initial tests have it a bit hotter than my old setup. I'm running low 80s pulling from an ambient temp of low 70s.
Going forward into winter my garage temp will drop so that will help plus I'll avoid daytime lights on.
 

Pinworm

Well-Known Member
72-76F during flower. You can get away with higher temps when they are seedlings/cuts. 80ish during veg is acceptable. Low 80s is not that bad during flower. Toss a few extra circulation fans in there and you should be good. Once you start hitting upwards of 83+ then you really need to start worrying. Heat can really stress them out. I bought a cheap AC window unit at a garage sale for 50 bucks, and I like to run it constantly. Even during the winter. Temp is a big deal. Good on you for looking out.
 

TedeBoy

Well-Known Member
72-76F during flower. You can get away with higher temps when they are seedlings/cuts. 80ish during veg is acceptable. Low 80s is not that bad during flower. Toss a few extra circulation fans in there and you should be good. Once you start hitting upwards of 83+ then you really need to start worrying. Heat can really stress them out. I bought a cheap AC window unit at a garage sale for 50 bucks, and I like to run it constantly. Even during the winter. Temp is a big deal. Good on you for looking out.
I've got 4" fans. One pulling and the other pushing from the bottom.
I may have to get at least a 6" pulling.
 

Kevin the Great

Well-Known Member
Shit, my plants hit 90-95 sometimes. Once my fan got jammed and it was over the max on my thermometer at 110 and my plants were fine. If you're growing outdoors and it's summer it gets close to 100, right? Ideal growth might be around 73 to 76 but they're tough, they can handle a lot more than that.
 

GroErr

Well-Known Member
During mid summer I can hit 85-87F with both lights running but the plants do get stressed more. I do like how they respond around the 78-82F mark which is my target and temp most of the year.
 

TedeBoy

Well-Known Member
During mid summer I can hit 85-87F with both lights running but the plants do get stressed more. I do like how they respond around the 78-82F mark which is my target and temp most of the year.
One of my biggest mistakes learning indoor growing is under ventilating. I'm still playing catchup.
I've settled now on a 6" Hyper Fan @ 315 cfm, a 6" "Skinny" Phresh filter, and 1 sq ft of passive intake.
I'll be testing out soon.
 

GroErr

Well-Known Member
One of my biggest mistakes learning indoor growing is under ventilating. I'm still playing catchup.
I've settled now on a 6" Hyper Fan @ 315 cfm, a 6" "Skinny" Phresh filter, and 1 sq ft of passive intake.
I'll be testing out soon.
Anytime you make a major change like lighting it takes a bit of monitoring/adjusting to get it dialed. If the passive intake doesn't reduce temps to your liking and the air outside your space is cooler, an inline intake fan with variable controller can be an good way to reduce/control your temps. If that air you pull in is dry it can also be a good way to reduce your RH.
 

PURPLEB3RRYKUSH

Well-Known Member
No problems with ventilation for me =))) i grow in a closet with just a fan in their, but doors on my closet are a tad open when lights on, only completely shut when lights off
 

shortdog420

Well-Known Member
No problems with ventilation for me =))) i grow in a closet with just a fan in their, but doors on my closet are a tad open when lights on, only completely shut when lights off
Thats exactly how ive always done mine, good thing we dont have to worry about smell!
 

Kevin the Great

Well-Known Member
I just checked my temps (3 separate microgrows) with a digital thermometer, one is 76, one is 82 and one is 85. The 82 and 85 are bagseed sativa in flower that seem to like the higher temps (luckily since I probably wouldn't change anything anyways) and the 76 is an Incredible Bulk auto that seems stunted :( waiting for some explosive growth but it might be in too hot of a soil.
 
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