Humidity

[Borderliner]

Hi all

got some conflicting info on the effects of humidity on a grow. If too high some say above 70% risk pm. But what if it's low say around 20-25% how will that affect the product?
Thanks b

 

[GreenLiberty]

I'm new, so I'm not sure either. My first grow attempt (last month) was a catastrophe due to the fact that I neglected to respect the recommended environmental parameters. I learned that extremes should be avoided at all costs.

The good news is that there are a lot of different things that you can do to either add or remove humidity to/from your grow space. Cannabis growers seem to be a very creative and industrious bunch. So, look around the internet for inexpensive, DIY remedies.

I can share what I have learned from my trial and error so far.

Seedlings like 50%-60% relative humidity and temps between 72 and 80 degrees Fahrenheit. Like it? They love it! Plant health starts at the seedling stage. Just like any other living organism, the better start they get to life, the better their health will be in the long run. So make sure that your babies start off on the right foot. I hope this helps. Good luck, mate!

 

[bikhomes]

Mites love low humidity.

 

[rangergord]

Good question Borderliner. I have learned the answer through the school of hard knocks. I used to think low humidity was not a problem at least I had no mold when humidity was low so what could be the harm?

Low humidity leads to Vapour Pressure Deficit. VPD. GOOGLE IT! It leads to excessive evaporation and transpiration. The plant transpires and absorbs too much fertiliser as it takes in water leading directly to leaf tip burn and clawing. Evaporation and adsorbtion of water from the soil is also excessive and leads directly to salt build up, nutrient burn and lockout due to pH rise. Green Liberty is right about seedlings doing better in high humidity. The last month of flowering is when PM is a big risk so about 50 percent max for late flower. Up to that point I run 65 to 70 percent rH now because it is very important in dry climate.

 

[Borderliner]

Thanks for the info guys.

GreenLiberty

think I had all other environmental variables but humidity down on my recently finished first grow. When cut and hanging were ready to jar in 2 days which read is related to low rh. wonder if can effect the potency?
b

 

[Borderliner]

Good question Borderliner. I have learned the answer through the school of hard knocks. I used to think low humidity was not a problem at least I had no mold when humidity was low so what could be the harm?

Low humidity leads to Vapour Pressure Deficit. VPD. GOOGLE IT! It leads to excessive evaporation and transpiration. The plant transpires and absorbs too much fertiliser as it takes in water leading directly to leaf tip burn and clawing. Evaporation and adsorbtion of water from the soil is also excessive and leads directly to salt build up, nutrient burn and lockout due to pH rise. Green Liberty is right about seedlings doing better in high humidity. The last month of flowering is when PM is a big risk so about 50 percent max for late flower. Up to that point I run 65 to 70 percent rH now because it is very important in dry climate.

On my first and only grow so far rh was around 30 to 25 usually and they were one in 5gal and 2 were in 7gal pots. watered or feed once the pot was mostly dried, judged by the lifting the pot route. feed everyother time alternating with plain water and some molasses. And it took about 3 days for them to dry. Toward the end of the run was down to every other day. This was in supersoil and FF trio of nutrients. Never showed any burn or clawing. Think my girls were heavy eaters. Dried yield for the 3 plants was little over 16 ounces.

I understand your reasoning and have read the same. Thanks for helping.
b

 

[Oti$]

You want higher humidity, ~70% in veg up until about week 3 of flower or the end of stretch. Then 50% or lower through the rest of flower.

 

[rangergord]

Thanks for the info guys.

GreenLiberty

think I had all other environmental variables but humidity down on my recently finished first grow. When cut and hanging were ready to jar in 2 days which read is related to low rh. wonder if can effect the potency?
b

Oh yes it does! BIG TIME. Until last year my harvested buds were dry in 3 to 4 days. My dank buds lost most of their smell and especially flavour. THen I read the advanced curing threads in the harvest forum. Got an accurate hygrometer to measure humidity. Changed my methods to provide a drying environment in my closet that was 70 % rH. Doubled and trippled the time to dry. To my amazement my buds were the stickiest, smelliest, most flavour packed ever. The potency was way up. When I think of the years I spent ruining my harvests by drying them in low humidity, I could cry!

 

[Borderliner]

Oh yes it does! BIG TIME. Until last year my harvested buds were dry in 3 to 4 days. My dank buds lost most of their smell and especially flavour. THen I read the advanced curing threads in the harvest forum. Got an accurate hygrometer to measure humidity. Changed my methods to provide a drying environment in my closet that was 70 % rH. Doubled and trippled the time to dry. To my amazement my buds were the stickiest, smelliest, most flavour packed ever. The potency was way up. When I think of the years I spent ruining my harvests by drying them in low humidity, I could cry!

rangerord

hey thanks that's what I'm looking for first hand experience.
b

 

[Granger2]

Found out the hard way that too low humidity in last 4 weeks of bloom caused terpenes to evaporate, leaving buds with little smell, taste. Good luck. -granger

 

[Saltlife]

Border you get so you can private message
Im trying gey my count up so i can
whats it take 50

 

[Borderliner]

yeah need 50 to pm

 

[Saltlife]

Ok thanks

 

[HarvestMoon303]

my buddy had a plant die on him in one of the 15gl, he uses it now for humidity by just keeping it watered and keeping it in the middle. no plant in it, just premix bx to help retain the moisture. really helps if you have the leftover material, if not invest in the triton 707 for the easiest/optimal results.

Sounds like this would just be a breeding ground for pests/mold. Soil that just stays wet and stagnant all the time?