Q: What’s the ideal % of humidity to flower in ?

[Bud]

I am presently growing 6 autos under a 315 LEC, with about30 days to go. I can raise or lower my humidity to sute. Not sure what’s the best % for buds?
Any information at all would help! Thanks

 

[Barney86]

Most go for around 50% for bloom mate. 60%+ increases the risk of various related problems. You know what VPD (vapor pressure deficit) is? If not then go have a quick Google. Really handy to know and keeps things as healthy as can be regarding environment.

 

[Aroxol]

Really depends on how dense the foliage/ canopy is and what your airflow situation is like above, below, and through the plants. VPD is great and definitely can improve growth, but can also lead to mold if you have big buds and non optimal air circulation.

 

[Barney86]

Yeah definitely right there growca. All stands for nout if there's not enough airflow.

 

[Aroxol]

Having lost an entire crop to mold once, trying vpd on my last grow was a very nerve-racking experience. While I definitely saw very explosive growth going by the VPD chart, I don’t know if it’s something I’ll sustain, at least not in mid to late flower. With 4 weeks left I’d probably stick to 50% and wind down towards the last two weeks.

 

[Barney86]

Having lost an entire crop to mold once, trying vpd on my last grow was a very nerve-racking experience. While I definitely saw very explosive growth going by the VPD chart, I don’t know if it’s something I’ll sustain, at least not in mid to late flower. With 4 weeks left I’d probably stick to 50% and wind down towards the last two weeks.

I almost got screwed with bud rot last year. Had an auto with a main like a 2L bottle and it crumbled like a bitch. Was gutted. Biggest bud I've had and lost the full thing. Chopped early enough though so was an isolated incident. Was poor airflow in my case. Lesson learned though.

 

[Bud]

I’m growing in a closet 4x8x8’ covered in Mylar,with a 8x20” opening at the bottom to allow air in and a 440 pulling air thru to the top and out to the attic with two oscillating 6” clip on fans and a tower fan
Air movement is not a concern. I also defoliate the hell out of my girls along with topping and LST to try and avoid any mold, keeping the buds at least a inch apart from each other as thay get taller.
I’ve been keeping it at about 30%, I’ll up it a bit, thanks for the info

 

[Hdinkleman]

I’m growing in a closet 4x8x8’ covered in Mylar,with a 8x20” opening at the bottom to allow air in and a 440 pulling air thru to the top and out to the attic with two oscillating 6” clip on fans and a tower fan
Air movement is not a concern. I also defoliate the hell out of my girls along with topping and LST to try and avoid any mold, keeping the buds at least a inch apart from each other as thay get taller.
I’ve been keeping it at about 30%, I’ll up it a bit, thanks for the info

keep it low dont need to raise it past 30, i wouldnt worry about it

 

[Emilya Green]

The perfect RH is what would normally occur in that strain's natural home environment. Since so much of what we grow anymore is a hybrid, that is no longer such a concern since many of our hybrids are designed to grow in the areas that we are growing in. High humidity at the VPD point is a good idea, as long as you have the air movement to support it.

This being said, once the buds start forming, around week 4 or 5, you want to start reducing the humidity so as to avoid moisture building up in the buds. By the end of flower, I will be trying to get my humidity down at least to 30, and lower would not offend me.

I know you just asked about flower, but when I get to the drying tent, I want high humidity again to promote slow drying. There really isn't a simple answer about perfect humidity while growing cannabis.