Can humidity be too low the last couple weeks?

A.k.a

Well-Known Member
I’m in week 12 of flower and because I live in the desert I can easily drop the rh into the low 20s.

I’ve read a few guides that say low rh at the end is good for resin production, but is 25% too low?
 

RadicalRoss

Well-Known Member
What are your temperatures in the tent like?

My personal advice is that this is far too low. I had set my humidity to 30% with temperatures upwards of 85 when lights were on. I basically had to bin the whole thing, my buds were super light and air. Complete waste of my time.

I'd look at a VPD chart and base your humidity setting on that. I had another group of plants in that same tent that I just harvested, lowest I ever set the humidity to was 55. Wasn't a perfect harvest, but there's a lot more product than in my last one
 

ZeeeDoc

Well-Known Member
On the positive if you have nice fat colas, that low humidity should deter bud rot from forming, and yeah if your in last couple weeks ladies be fine and possibly increase trichomes production.
 

Dank Bongula

Well-Known Member
Too low for me, I'll run a small personal humidifier or hang some wet rags in the tent to boost humidity up to 40-50%

If I ran that low of humidity, I would get spider mites
 

Jjgrow420

Well-Known Member
In the winter my rh drops sometimes to less than 20% all I notice is more resin production. I also lower my ec as the plant will want to suck back more water because it's loosing alot quick. I'll run a humidifier but it barley gets me over 25%
Hot and dry bad
Cool and dry not as bad
 

A.k.a

Well-Known Member
Temps are 73-80.

they probably only have 7-10 more days to go so there’s no size issue.


it is crazy how quick they dry out when rh gets below 45.
 

Flowki

Well-Known Member
As far as I've read, humidity lower than 50% is going to lead to problems (50 is also low). The only exception may be some kind of arid desert strains, but I'd go on a limb to say most of us don't have that trait, given all the crosses over the years.

When the humidity drops low, the plant has to take up more water, just like humans sweat when hot. Because the plant is taking up more water, containing nutrients, it may take up more nutrients than it needs, leading to toxicity, it has no good choices at that point. The other outcome is that the medium dries out between watering due to plant using more water, and your roots dry out, and then exposed to the salts that have now solidified and become toxic. That will kill a plant, depending on your ppm levels and how much the medium dries out.

When the air is dry, your fans will also run a much higher chance of wind stressing the leaves, dry and crispy. I'm just guessing here, but I would assume dry leaves are also more prone to heat stress. As another pointed out, that may produce more resin, but I get the feeling it is like a damaged tree producing sap, not really a ''positive'' upside. Or plainly put, I'd rather the plants where comfortable, spending every last bit of available energy on stacking weight, or at-least stopping it from re-considering it's gender options.
 

Jjgrow420

Well-Known Member
As far as I've read, humidity lower than 50% is going to lead to problems (50 is also low). The only exception may be some kind of arid desert strains, but I'd go on a limb to say most of us don't have that trait, given all the crosses over the years.

When the humidity drops low, the plant has to take up more water, just like humans sweat when hot. Because the plant is taking up more water, containing nutrients, it may take up more nutrients than it needs, leading to toxicity, it has no good choices at that point. The other outcome is that the medium dries out between watering due to plant using more water, and your roots dry out, and then exposed to the salts that have now solidified and become toxic. That will kill a plant, depending on your ppm levels and how much the medium dries out.

When the air is dry, your fans will also run a much higher chance of wind stressing the leaves, dry and crispy. I'm just guessing here, but I would assume dry leaves are also more prone to heat stress. As another pointed out, that may produce more resin, but I get the feeling it is like a damaged tree producing sap, not really a ''positive'' upside. Or plainly put, I'd rather the plants where comfortable, spending every last bit of available energy on stacking weight, or at-least stopping it from re-considering it's gender options.
That's why you don't feed and water blindly you need to know what the plants doing at all times. Just because it's dry doesn't mean you need a special strain lol. The plant will only take up nutrients when it needs to. If it's hot and dry it'll take up more water than nutrients leaving an accumulation of salts in your medium. That's why you monitor your feeds and runoff and soil pH so you know what's going on. Never had an issue with it being too dry lol
 

Flowki

Well-Known Member
That's why you don't feed and water blindly you need to know what the plants doing at all times. Just because it's dry doesn't mean you need a special strain lol. The plant will only take up nutrients when it needs to. If it's hot and dry it'll take up more water than nutrients leaving an accumulation of salts in your medium. That's why you monitor your feeds and runoff and soil pH so you know what's going on. Never had an issue with it being too dry lol
You can not read your plants in a randomly fluctuating environment (as in constant outside airflow), all you can do is react and hope you catch things in time. That's why growers try to keep a steady environment with automated controllers, to avoid random outside weather.

I did not say you need a special strain, don't change my words please.

People in hydro get nute burn or toxicity, it's never dry there and the plants always have access to water. At some point they are clearly taking up nutes or reacting to toxic conditions at the root level.

If you know the elemental ppm you are putting in, and avoiding desert conditions, there is no need to ever check run off. Learning the EC of run off is very unique to each grower, it's relative, you can only learn it from first hand trial and error of your own particular readings, yet you've never had any issues?.
 

Jjgrow420

Well-Known Member
You can not read your plants in a randomly fluctuating environment (as in constant outside airflow), all you can do is react and hope you catch things in time. That's why growers try to keep a steady environment with automated controllers, to avoid random outside weather.

I did not say you need a special strain, don't change my words please.

People in hydro get nute burn or toxicity, it's never dry there and the plants always have access to water. At some point they are clearly taking up nutes or reacting to toxic conditions at the root level.

If you know the elemental ppm you are putting in, and avoiding desert conditions, there is no need to ever check run off. Learning the EC of run off is very unique to each grower, it's relative, you can only learn it from first hand trial and error of your own particular readings, yet you've never had any issues?.
Lol k
 
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