How Humidity Affects The End Result!

[AutoDaddy]

Hello to everyone,

I've decided to post this thread so people can avoid an issue I've experienced a few times over the last 5 years growing autos.

Simply, if the humidity is too low throughout flowering then nutrients can get 'locked' into the buds and CAN'T be flushed, causing bad tasting weed no matter how long you cure.

I've experienced this in 4 different auto grows all where relative humidity was less than 30% during flower, recommended RH for autos is around 60% throughout the grow.

If you live in a dry climate or have issues with low humidity it is definitely worth investing into a humidifier.

 

[Death The Cultivator]

Hello to everyone,

I've decided to post this thread so people can avoid an issue I've experienced a few times over the last 5 years growing autos.

Simply, if the humidity is too low throughout flowering then nutrients can get 'locked' into the buds and CAN'T be flushed, causing bad tasting weed no matter how long you cure.

I've experienced this in 4 different auto grows all where relative humidity was less than 30% during flower, recommended RH for autos is around 60% throughout the grow.

If you live in a dry climate or have issues with low humidity it is definitely worth investing into a humidifier.

That's just asking for problems sub 40%.

Read about the below? https://www.dimluxlighting.com/knowledge/vapor-pressure-deficit-vpd-calculator/

Interesting thread around here about flushing as well.

 

[Mañ'O'Green]

@AutoDaddy Welcome to AFN Nutrients that have been transported into the plant can never be "Flushed Out" period. This is a proven scientific fact.

Mostly Low but also too high RH will cause the stoma on the plant to close and stop the potential loss of water. This in turn stops transpiration - water moving through the plant and therefore the uptake of nutrients. This will cause nutrient deficiencies and the appearance of a lock-out.

If the plant cannot intake the nutrients it needs it will not be able to make terpenes or any cannabinoids. This is why your weed is worthless.

So your observation is correct it is just happening for different reasons.

You already understand the need for proper RH in the grow and there is an entire science behind it called VPD Vapor Pressure Deficit.
This chart is based on a leaf temperature -2°F lower than the ambient temperature of your air.

All of the good science aside I live in a desert and these numbers are not possible for me when the outside RH is ZERO! I shoot for >40%<60% RH. If I have really dense colas I try to stay close to 40% in late flower.

 

[AutoDaddy]

@AutoDaddy Welcome to AFN Nutrients that have been transported into the plant can never be "Flushed Out" period. This is a proven scientific fact.

Mostly Low but also too high RH will cause the stoma on the plant to close and stop the potential loss of water. This in turn stops transpiration - water moving through the plant and therefore the uptake of nutrients. This will cause nutrient deficiencies and the appearance of a lock-out.

If the plant cannot intake the nutrients it needs it will not be able to make terpenes or any cannabinoids. This is why your weed is worthless.

So your observation is correct it is just happening for different reasons.

You already understand the need for proper RH in the grow and there is an entire science behind it called VPD Vapor Pressure Deficit.
This chart is based on a leaf temperature -2°F lower than the ambient temperature of your air.

View attachment 1305438View attachment 1305439

All of the good science aside I live in a desert and these numbers are not possible for me when the outside RH is ZERO! I shoot for >40%<60% RH. If I have really dense colas I try to stay close to 40% in late flower.

Thank you so much for providing the scientific biological info as to why this problem occurs!

It's so depressing harvesting a strain you love and have excelled with before only to end up with tasteless herb.

Thanks again

 

[DDubs]

I ended up buying full adjustable mini humidifier and a dehumidifier. My tent it small and they take up about a 1/4 of the space but my plant looks so much healthier with the controls.

I look forward to a enjoying controlled cure. My first attempt was heart breaking. I still smoked it though.

 

[AutoDaddy]

I ended up buying full adjustable mini humidifier and a dehumidifier. My tent it small and they take up about a 1/4 of the space but my plant looks so much healthier with the controls.

I look forward to a enjoying controlled cure. My first attempt was heart breaking. I still smoked it though. View attachment 1305729View attachment 1305730

Thanks for sharing man,

I've had problems with mould in the past, late in flower, which made me over compensate by keeping humidity far too low throughout the majority of flowering and we know how that ends up.

Have you had to deal with any of the dreaded bud rot before?

 

[DDubs]

Thanks for sharing man,

I've had problems with mould in the past, late in flower, which made me over compensate by keeping humidity far too low throughout the majority of flowering and we know how that ends up.

Have you had to deal with any of the dreaded bud rot before?

I had some issues the last time. It was tough to screw up so late in the game. I'm going to pick up another fan to try and add more air circulation this time. But all in all, my plant health its above and beyond my last grow.