New Grower Low humidity and high temps?

[mlorE]

Hey people.

If you have low humidity and high temps, is it really bad?
if so, what could the repocussions be?

Reason being i have been having 20%-30% RH and 33 degrees C.
they are half way through the flowering stage.
Also i dont seem to be having any problems, everything looks fine and good. all forming okay. No heat stressed leaves or anything.
Only thing is some leaves are starting to go yellow from the bottom, but im not too worried about that. , As i think thats to do with nitrogen.

They are in the 30-33 degrees Celsius area/91 f for about 10 hours out of the 20 on.

i would get some pics, but cant at the moment.

Thanks

 

[Nero]

Hi Mlore

From my research I can tell you that anything above 30 c is not advisable, although there are some strains that could tolerate the heat better than others. Also for flowering is advisable anything from 40 to 50 % RH but I think is better to be dryer than more humid because of moulding in the second scenario. I am just in my first grow, but thats what I can tell you about the subject, I hope it helps a bit.

Maybe you could search for pics of how cannabis looks when they are in low humidity conditions and in heat stress condition and try to compare your girls to them, If you detect some signs of a problem try to make some changes in the grow tent.

 

[Cat]

Plants prefer temps of 20-30C and humidity during the flower period should be 40 to 50%. I struggle to keep the temps lower than 30C, but a new exhaust fan did help. My humidity in flower usually sits between 55-60%, which isn't ideal, but as long as I have plenty of air blowing over the plants, it hasn't caused a problem so far. When I needed my humidity to be higher during veg, I put a bowl of water in the tent and hung a wet (not dripping) towel over the bars, that definately raised the humidity. Do you have high temps outside? Maybe you need a better exhaust/carbon filter fan to remove more heat.

 

[mlorE]

Plants prefer temps of 20-30C and humidity during the flower period should be 40 to 50%. I struggle to keep the temps lower than 30C, but a new exhaust fan did help. My humidity in flower usually sits between 55-60%, which isn't ideal, but as long as I have plenty of air blowing over the plants, it hasn't caused a problem so far. When I needed my humidity to be higher during veg, I put a bowl of water in the tent and hung a wet (not dripping) towel over the bars, that definately raised the humidity. Do you have high temps outside? Maybe you need a better exhaust/carbon filter fan to remove more heat.

I'm such an idiot. I've checked my intake and outake.
I've put em round the wrong way. I've got the 720 for intake and the 420 for outake.
Basically I'm pushing in more air than I can take out. I'm so annoyed with myself. All this time.

It is very hot out at the mo, so that won't help. I think putting the intake/outake round the right way will sort it out tho. Already gone down to 29.6 and gone up to 26 rh.

Although growth looks fine. I've got two in there that look at least a week behind the rest. Maybe that's because of the heat, I dunno? Just a thought.

 

[Cat]

@mlorE I have two Northern Lights growing and one is completely different from the other. The eldest is only 15" tall, while the other is over 2.5ft....so, the heat issue might not be the reason for your variation. I am usually happy if my tent goes bellow 30C, yesterday and today it hovered at 29C. Just remember to blow lots of air over them with an osculating fan. Another trick I found useful is to point a small fan upwards from bottom of the tent, it helps to push the hot air up to top of tent to be extracted by filter, it does help. I think changing the intake/out will make a huge difference, but I would try to get those humidity levels up slightly

 

[2Stoned2Care]

if you want to get your rh up just put some bowls of water or wet towels in the grow room.or the best way without a humidifier is to get a fine spray bottle and spray the walls

 

[Cat]

if you want to get your rh up just put some bowls of water or wet towels in the grow room.or the best way without a humidifier is to get a fine spray bottle and spray the walls

Yes, this worked really well for me during veg

 

[G.Leave]

Hey...I grow out in the winter in a small space with a lot of light..temps are usually 85 degrees, but due to winter, humidity is insane low, as low as 18%, but normally around 22%RH. Plants will grow fine in a low humidity. I would much rather have low humidity than high!!

 

[GodAmJT]

I would much rather have low humidity than high!!

I can attest to this statement, as my last grow, I lost 3 of my 4 plants to mold, and I only had humidity issues for about 2 weeks of the grow, where my humidity reached the 70%'s, so now I run a dehumidifier in my area and my RH stays at 40%-ish, only rising to a low 50% if I forget to dump the dehumidifier reservoir.. I don't think I'll ever grow without one now.. It's not always an option for a lot of guys, so even doing things like changing the lighting cycle so that the lights are off during the hottest part of the day (usually the least humid as well) can help regulate both temp and RH..

 

[Cat]

I can attest to this statement, as my last grow, I lost 3 of my 4 plants to mold, and I only had humidity issues for about 2 weeks of the grow, where my humidity reached the 70%'s, so now I run a dehumidifier in my area and my RH stays at 40%-ish, only rising to a low 50% if I forget to dump the dehumidifier reservoir.. I don't think I'll ever grow without one now.. It's not always an option for a lot of guys, so even doing things like changing the lighting cycle so that the lights are off during the hottest part of the day (usually the least humid as well) can help regulate both temp and RH..

Can I ask if you run your dehumidifier inside the grow tent? Is it a large growing area you have? I've been thinking of a dehumidifier. I bought a small one, but it makes no difference