what is the highest temperature youll get away with?..

switch

Well-Known Member
what is the highest limit of temps inside a grow tent you can have before it literally STOPS growing? I keep getting told 25degrees is the best temps, and anything over 30 is the worst, but i grow at 33 most of the time without too many problems...
 

TaoWolf

Active Member
Growth probably stops somewhere around 38-40 Celsius (while just starting to slowing down around 32+ Celsius). Converted from Fahrenheit numbers so might be a little off.
 

reggaerican

Well-Known Member
Growth probably stops somewhere around 38-40 Celsius (while just starting to slowing down around 32+ Celsius). Converted from Fahrenheit numbers so might be a little off.
i would say 32+ is all bad for your plants 35 will stop growth completly
 

NateDizity1420

Active Member
My tent has 2 400w hps bulbs in it now and w/ the exhaust fan & floor/ceiling fans it stays between 78-88 F. Before I had my fans it would get up to 95-98 F and this seemed like it was starting to make my plants wilt. I dont like letting them get over 89 F. This summer my out door crop took 2 weeks of 95 F and above weather like champs, but there were a couple that got killed off because of the extreme heat. So depending on the strain your growing your plants may be able to take high temps w/ no problems that other strains might wilt and die in. If I was you id try and keep your heat down around 85F at the highest.
 

Nullis

Moderator
Anything above 30 Celsius/86 Fahrenheit should be avoided. Such high temperatures result in stretchy plants with smaller, airy buds.
Some strains will handle high temperatures better than others. What must be understood is that high temperatures in an indoor grow room are more potentially devastating to the plants growing within it, as opposed to plants growing outside in a hot environment. Outside the temperatures fluctuate depending on the position of the sun in the sky, and local whether patterns. There is also constant airflow to plants which are grown in an open atmosphere.
Indoors, carbon dioxide is quickly depleted from the air and it is just stagnant. If you want to grow in temperature exceeding 90 degrees, carbon dioxide enrichment becomes a necessity.
 

diamonddave

Active Member
thr highest my temp in my tent gets in 89F, but thats with plently of air circulation and it doesnt seem too hot under the 250... so is it ok to have these high temps if there is a fan blowing in between the light and the canopy?
 

TaoWolf

Active Member
thr highest my temp in my tent gets in 89F, but thats with plently of air circulation and it doesnt seem too hot under the 250... so is it ok to have these high temps if there is a fan blowing in between the light and the canopy?
Should be fine even if not optimal. Just for perspective, I've had plants make it through long periods of 100+ degree heat outdoors with temps being in the upper 90s most of the summer. They did seem to slow down at those temps, but it didn't kill them. Although, sativa dominant strains are going to do better than indica dominant strains at higher temperatures, so your mileage may vary.
 

Dwezelitsame

Well-Known Member
just keep good air circulation

i read a piece by hobbs about his air floor so now i have a tower oscelating and a fan on floor bowing air to bottom of my leaves for stomas i liked the approach of the hobbs experiment

both vents in tent are open so even with my adv temp over 90 plants do fine

top view of tent drawing easyer to understand then pic





one of reasons im so hot cause of enternal ballast on one light my first light still keep for now to go one day use for veg setup and get replacment for flower
 

homebrewer

Well-Known Member
Anything above 30 Celsius/86 Fahrenheit should be avoided. Such high temperatures result in stretchy plants with smaller, airy buds.
Some strains will handle high temperatures better than others. What must be understood is that high temperatures in an indoor grow room are more potentially devastating to the plants growing within it, as opposed to plants growing outside in a hot environment. Outside the temperatures fluctuate depending on the position of the sun in the sky, and local whether patterns. There is also constant airflow to plants which are grown in an open atmosphere.
Indoors, carbon dioxide is quickly depleted from the air and it is just stagnant. If you want to grow in temperature exceeding 90 degrees, carbon dioxide enrichment becomes a necessity.
I'm going to disagree here. Hot days in my grow room get up to 32C/90F and my buds aren't airy. I'm not even sure that stretching is even relevant in this case as in the winter, my plants are structurally the same as they are in the summer where I sometimes see high temps. As always, there are a variety of factors and YMMV.

I do agree that 30/86 is high enough but going hotter isn't so detrimental that it is to be avoided at all costs.
 

diamonddave

Active Member
i def agree with u homebrewer, i mean guys lets get real, the outdoors gets wayyy hotter than 86, and yes i know that the airflow and breeze in endless but still, even in a hot growroom, as long as there is plenty of circulation and a breeze for the ladies, growth should not stop nor be halted.
 

switch

Well-Known Member
Sweet, nice one for the replies guys, good info there...

How much does humidity affect plants, as i recently bought a tiny fogger, cos my humidity was never above 25% wich i understand is far too dry, but the fogger doesnt do a great deal, it pushes the humidity up to 47-50% at best. I wanted it to go to 80% for the veg stage. How important is this, or should i just take the fogger back for a refund and not worry about humidity being too dry???
 

Serapis

Well-Known Member
My closet hits 85-90 all the time and my ladies seem to be loving it. The humidity is 45% constant. I do open the door during lights on to let them get some cooler air from time to time though.
 

mashroom777777

Active Member
Before buying a good fan I was hitting over 100 f girls seem to do fine.No different than hot summer days.
it's not the same thing indoors and outdoors,outdoors temperatures rises over 30c just for a few hours,also ventilation is much better outdoors but indoors, high temperatures last for 18hrs at least thus damaging the plant.i had 3 easy ryders in a grow room while summer,with temperatures of 38c,sometimes even 40c for 18hrs a day and the plants got shitty without a lot of thc,tasteless and not potent at all.i'm quite sure high temperatures affects badly the quality of the final product.
 

mashroom777777

Active Member
i def agree with u homebrewer, i mean guys lets get real, the outdoors gets wayyy hotter than 86, and yes i know that the airflow and breeze in endless but still, even in a hot growroom, as long as there is plenty of circulation and a breeze for the ladies, growth should not stop nor be halted.

my friend indoors the temp is over 30c for at least 18hrs (which is too long)but outdoors only for 5-6 hrs(noon time) ,take this also into consideration.. so it couldn't possible be the same thing(indoors and outdoors)
 
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