Mephisto Genetics Nutrient uptake vs water uptake and relative humidity

[lunarman]

I could have posted this on the nutrient board but it doesn't get much traffic. and this does pertain to growing some Mephisto gear right now so there you go.

I have been playing with relative humidity. I live in an arid climate with a grow tent in an external garage. I have to add a humidifier to my tent to get over 50% RH. I'm also trying to play around with VPD and dialing in a good tent temperature and RH so that I'm in the green zone.

When i have the humidifier on and RH is above 60% I notice the coco stays moist longer than if I had a lower RH. So I'm not watering as much right now, so therefore the plants are getting less what i call feed water.

I read with a good VPD setup with it dialed in to the "green" range on the chart plants will uptake more nutrients. But I am not watering as much with a higher RH. So it seems like a contradiction. How can less feed water in the system equate to more nutrient use?

Is it true that plants can uptake more nutes with good VPD setup, but you're actually watering less? Is that even possible? I'm thinking maybe my plants are loving the nutrients that are in the coco and uptaking it well with a higher RH, but they are not uptaking as much H20. Hoping that is the case from a botany science point of view.

 

[BII]

I think the answer is simple. At low RH, you are losing a lot more "feed water" to evaporation, both by the medium/soil and plant (transpiration). Much less water is lost at higher RH.

 

[lunarman]

I think the answer is simple. At low RH, you are losing a lot more "feed water" to evaporation, both by the medium/soil and plant (transpiration). Much less water is lost at higher RH.

A) I was hoping you would see this and reply.
B) I didn't realize it was that simple and thank god it is.
C) Do you subscribe to plants up taking nutes better when RH and Temp sets up an ideal VPD value? So in my case if I can get RH just above 60% I know there is less transpiration and I go thru less water, but the plant is going to like the nutrients a lot more and growth will be noticeably better. Is that an accurate statement?

 

[DABaracuss]

Yea man dont try to reinvent the wheel so to speak .Stick to the basics and then tweak it as you learn more and get better. Looks like your doing your homework though..You got this!

 

[lunarman]

Yea man dont try to reinvent the wheel so to speak .Stick to the basics and then tweak it as you learn more and get better. Looks like your doing your homework though..You got this!

So you're saying I shouldn't get in to the weeds? LOL. Thanks bro.

 

[MrGoat]

A) I was hoping you would see this and reply.
B) I didn't realize it was that simple and thank god it is.
C) Do you subscribe to plants up taking nutes better when RH and Temp sets up an ideal VPD value? So in my case if I can get RH just above 60% I know there is less transpiration and I go thru less water, but the plant is going to like the nutrients a lot more and growth will be noticeably better. Is that an accurate statement?

Thats pretty much it, during flower u want your RH btw 50-60%. On your denser strains high RH will cause more problems. I recently saw a study about the how many issues develop due to high humidity.
As someone else stated "Don't reinvent the wheel" when u do, do it one plant at a time.
Theres this guy on Youtube - The Grow Boss - hes a bit loud and obnoxious but one thing he says sticks with me. The object is to not F up, u screw up in week 2, it affects the plant till the end, same thing week 10.
With Autos having such a short life span, any issues just don't have enough time to correct.
That is one of the reasons I love growing autos, everything is crucial
Off my soapbox now.
Cheers!

Sent from my SM-N960U using Tapatalk

 

[BII]

C) Do you subscribe to plants up taking nutes better when RH and Temp sets up an ideal VPD value? So in my case if I can get RH just above 60% I know there is less transpiration and I go thru less water, but the plant is going to like the nutrients a lot more and growth will be noticeably better. Is that an accurate statement?

I would presume "ideal VPD value" is not all that relevant to well-tended and watered/fed indoor plants, with sufficient air circulation. These plants are both simple and adaptable enough, particularly when tended in a tent (vs. outside) and kept well watered/fed, such that they are rather tolerant in terms of RH (with temperature more important, but for reasons mostly other than 'ideal VPD'). A spoiled well-fed plant is not going to care much about RH. Plant cells/tissues/organs take up nutes they need from surrounding fluids. Plant cells/tissues/organs are not going to speed-up or slow-down, make more or less good stuff, just because of faster or slower flow (here driven by transpiration with water vapor exiting mostly via stomata/underside of leaves) of the water/nutes outside the cells/tissues/organs.

 

[MrGoat]

I would presume "ideal VPD value" is not all that relevant to well-tended and watered/fed indoor plants, with sufficient air circulation. These plants are both simple and adaptable enough, particularly when tended in a tent (vs. outside) and kept well watered/fed, such that they are rather tolerant in terms of RH (with temperature more important, but for reasons mostly other than 'ideal VPD'). A spoiled well-fed plant is not going to care much about RH. Plant cells/tissues/organs take up nutes they need from surrounding fluids. Plant cells/tissues/organs are not going to speed-up or slow-down, make more or less good stuff, just because of faster or slower flow (here driven by transpiration with water vapor exiting mostly via stomata/underside of leaves) of the water/nutes outside the cells/tissues/organs.

Very well put Mr Bill, very well indeed.

Sent from my SM-N960U using Tapatalk

 

[slowandeasy]

You are trying to be too precise bro. I am all for having a dialed In environment, but you don't need to over think things. 60+ Humidity is good for veg. But not Ideal for Flower. Honestly, I would rather have lower Humidity and feed more often my whole grow. Good luck

 

[Steviestash]

Thats pretty much it, during flower u want your RH btw 50-60%. On your denser strains high RH will cause more problems. I recently saw a study about the how many issues develop due to high humidity.
As someone else stated "Don't reinvent the wheel" when u do, do it one plant at a time.
Theres this guy on Youtube - The Grow Boss - hes a bit loud and obnoxious but one thing he says sticks with me. The object is to not F up, u screw up in week 2, it affects the plant till the end, same thing week 10.
With Autos having such a short life span, any issues just don't have enough time to correct.
That is one of the reasons I love growing autos, everything is crucial
Off my soapbox now.
Cheers!

Sent from my SM-N960U using Tapatalk

I've seen a lot of those grow boss episodes 2 and the one thing that sticks with me about him is that he also says you can't run things at 100% if you can run things 70 80% you're doing good