max room temps a plant can handle?

[zelli]

hey guys, i've been reading around the forum on max temps at plant height. i've been growing a good while now but have since changed my grow space and this will be the first summer! i've read here that some people swear that room temps can be real high, like 40C+ as long as you keep their roots cool. now in theory this sounds fine but in reality (at least mine) once the temps gets to about 35C the leaves begin to dry out and turn up at the edges, and if left this way for a day or two would turn crisp. now i'm not sure if in this state they still function at all? i'd like to know... also can anyone point me in the direction of a graph/guide on max temps for plants etc? like what exact temps leaves do start to dry out, ways to prevent this occuring etc? in my previous grow rooms i'd always managed to keep a handle on this but for the first time i'm down sized and in a tent, so missing the insulation i once enjoyed.

 

thanks zelli

[sheep_dreamer]

I'll lay down an idea on this zelli. What if it's the leaves drying out and curling up because their not getting water up from the roots which are too dry. So the ambient temp is not so much of a factor, as it's the roots which need to have water. Also, I'll go out on a limb and offer that the majority of Cannabis could grow fine in 40deg temp leaving aside humidity and mould etc. as well as other factors like root rot in hight temp.... So ambient temp high, root medium temp low / wet / fresh, humidity fine... Cannabis ok

 

With the grow space situation and the heat, I'm thinking it'll be the leaves touching or coming too close to lights which will cause damage. This damage would be more a case of combustion. If you've been growing a while you're probably on to that.

 

Happy to discuss. - sorry no graph from me

[zelli]

hi sheep - thanks for your reply.

 

my pots are nicely fed so its not a water shortage issue. just a phenomenon of a few of the leaves at the top (that may have been slightly closer to the lamp) here and there. and this is most likely all im dealing with, but as my plants are only 3 weeks into vege in the tent i started to wonder if it was simply the latent heat, maybe interested someone knows of a resource on the topic for a readup.

 

thanks again

[Minzone]

This is the best article on temps http://www.growweedeasy.com/temperature

 

All the articles on that site are good tbh

[The Stoned Jester]

Yes im quite interested in this too, as my new cupboard is kinda outside, inside the garage really but it opens out to the patio so it does get quite hot under there.

 

 

better question yet are there some well known heat resistance strains? maybe something like an Afghan or something used to growing in hotter/drier climates.

[zelli]

thank minzone, that's exactly the kind of reading i was hoping to find online

[herby]

my last few grows were seeing temps of 40+c and they turned out sort of ok, most of my plants went hermie though towards the end..

My current grow is alot better due to an upgrade in exhaust fan setup.

[Frank Reynolds]

Prob tips or leaves getting to close to the light getting burnt/bleached

 

I've had canopy temps of 40+ last summer 30ish around roots, absolutely no problems other than making sure to lower my ec.

[Sixty-Eight]

from memory mine has peaked around 50c only for a day or two in summer the key is good ventilation and have good airflow around the plants, dont sink your light right down ontop of your plants have it at a good height so u can maintain airflow over the canopy

 

if u have it set up ok and your drawing in air from outside than u should see minimal leaf curl just make sure any leaf curl is only at the top of the plant and not all over

 

another good key is keep the plants well watered if in soil or coco