Vapor Pressure Deficit or VPD. Which chart is right and why so much variance?

[smoke]

With your temps around 80, do you run a chiller? I've kept mine 74-77 and my water temps have remained 72-74.

You may be in dirt, sorry if I missed that somewhere.

I run a 4 site current culture 13 gal in my veg and in my flower with a chiller for each room set at 68 f

78 deg leaf temp is what i look and i actually run my room around 82 using hps lights. Room temp usually a couple degrees lower if running leds is my understanding

 

[IamN2pot]

With your temps around 80, do you run a chiller? I've kept mine 74-77 and my water temps have remained 72-74.

You may be in dirt, sorry if I missed that somewhere.

One is RDWC and the other is in super soil. My RDWC has a chiller set at 68*.

 

[Shaded]

I have to admit VPD is one of the vectors that I don't track or pay attention to. Mostly because I just don't have the means or methods at the moment for that level of control(no sealed room or temp/humidity controls). Nature doesn't seem to concern itself too much with VPD though and plants in the wild still thrive and survive?

I guess one could argue that if you grow good shit without monitoring VPD then dialing in your VPD can only produce better results?

 

[Aqua Man]

I have to admit VPD is one of the vectors that I don't track or pay attention to. Mostly because I just don't have the means or methods at the moment for that level of control(no sealed room or temp/humidity controls). Nature doesn't seem to concern itself too much with VPD though and plants in the wild still thrive and survive?

I guess one could argue that if you grow good shit without monitoring VPD then dialing in your VPD can only produce better results?

Most growers are naturally very close to ideal VPD but your absolutely right it can improve your grow… rarely does it hirt a grow…. But rather can result in high uptake of nutrients etc so you can address those issues instead of tweaking VPD. Lots of work arounds but VPD does play an important role and most are already close and don’t know it

 

[Rootsruler]

Most growers are naturally very close to ideal VPD but your absolutely right it can improve your grow… rarely does it hirt a grow…. But rather can result in high uptake of nutrients etc so you can address those issues instead of tweaking VPD. Lots of work arounds but VPD does play an important role and most are already close and don’t know it

Agreed. I keep pretty tight control of my environmental parameters and I've seen an improvement in yields.

I'd say most indoor growers do keep it generally in range since their plants live in the same environment the grower lives in but when there are wild swings that go uncontrolled for days on end then you will see a slowdown in progress. Humidity is one of those swings that is harder to detect and control without the right equipment to do it. Humidity, along with a few other factors, plays a major role in the plants performance. The fan controllers they use nowadays pretty much eliminate the need to have to manually control humidity while we try and dial in the fan speed that most closely stabilizes humidity level we are after at that moment.

 

[Shaded]

Most growers are naturally very close to ideal VPD but your absolutely right it can improve your grow… rarely does it hirt a grow…. But rather can result in high uptake of nutrients etc so you can address those issues instead of tweaking VPD. Lots of work arounds but VPD does play an important role and most are already close and don’t know it

Yeah that does seem to be a fair assessment. Bringing all the factors in line to optimize the metabolism. Like you can get good results going to the gym and working out, but if you dial in your workout program/diet/sleep/supplements your results are going to be vastly improved.

Just need to hold out for that sealed-room sponsorship

 

[Rootsruler]

Yeah that does seem to be a fair assessment. Bringing all the factors in line to optimize the metabolism. Like you can get good results going to the gym and working out, but if you dial in your workout program/diet/sleep/supplements your results are going to be vastly improved.

Just need to hold out for that sealed-room sponsorship

Perfect example!

 

[tobh]

re: the comment about not worrying about VPD in rooms smaller than 10 x 10. I will say I agree with this to an extent. *prepares for the tomatoes and lettuce shower*

IF a grower hyperfixates on getting VPD dialed in perfectly in a small space, they can lose hair with how quickly parameters can shift. Without having large volume to buffer against microshifts in climate, the entire environment reacts to a change in one parameter much more significantly. If the grower didn't have those pesky plants in the same space fucking with the variables, too, it would be super easy to dial in perfectly.

HOWEVER it's still important to at least try to get into the ballpark of the sweet spot. For new growers, I wouldn't throw this at them. They just need to get temps to 78F, RH to 60% and run with that. Once they get through a grow or two, then a topic like this absolutely should be something they start to learn about. Kinda like a growing child, we don't throw em on a bicycle when they're barely learning how to crawl.

 

[Rootsruler]

re: the comment about not worrying about VPD in rooms smaller than 10 x 10. I will say I agree with this to an extent. *prepares for the tomatoes and lettuce shower*

IF a grower hyperfixates on getting VPD dialed in perfectly in a small space, they can lose hair with how quickly parameters can shift. Without having large volume to buffer against microshifts in climate, the entire environment reacts to a change in one parameter much more significantly. If the grower didn't have those pesky plants in the same space fucking with the variables, too, it would be super easy to dial in perfectly.

HOWEVER it's still important to at least try to get into the ballpark of the sweet spot. For new growers, I wouldn't throw this at them. They just need to get temps to 78F, RH to 60% and run with that. Once they get through a grow or two, then a topic like this absolutely should be something they start to learn about. Kinda like a growing child, we don't throw em on a bicycle when they're barely learning how to crawl.

Yes. At The Hellhole I would advise newbs that wanted to start out using RDWC or some other more advanced technique to start in soil and master that first before you get into more labor intensive methods. Most of them see the pictures of the explosive growth but what they don't see is the guy pulling his hair out because pH dropped off a cliff or the system is sludging up or whatever the issues that tend to come with more advanced methods.

I'm a lazy ass. Sure, I could go full hydro. I've run it successfully many times but there is so much more that needs to go into it and the time it takes in having to constantly monitor it just doesn't fit my current lifestyle. With dirt I have a buddy that can keep the girls healthy regardless of the abuse I put them through.

I use VPD more as a guide in regards to environment. The fact that I have a decently controllable lung room makes it easier to maintain a narrower parameter.

 

[tobh]

Yes. At The Hellhole I would advise newbs that wanted to start out using RDWC or some other more advanced technique to start in soil and master that first before you get into more labor intensive methods. Most of them see the pictures of the explosive growth but what they don't see is they guy pulling his hair out because pH dropped off a cliff or the system is sludging up whatever the issues that tend to come with more advanced methods.

I'm a lazy ass. Sure, I could go full hydro. I've run it successfully many times but there is so much more that needs to go into it and the time it takes in having to constantly monitor it just don't fit my current lifestyle. With dirt I have a buddy that can keep the girls healthy regardless of the abuse I put them through.

yeah, that's my one rub with hydro, getting it to a state of equilibrium then not fucking with it too much aside from ongoing maintenance. can't really trust a buddy or babysitter to handle that kind of work when you're away though. hell, i had to fly out of town for work last year late in flower on my last run. left a simple 30 step instruction set for refilling the res for my ol lady to follow lol. was still biting nails hoping she did it right, but she managed fine then i fucked up it all up with a timer incident guess that proves your point haha

i never did good with soil, tbh. at least not with cannabis. just about anything else i can grow in it, even supposedly "hard to grow" plant varieties. cannabis, though... not so much. ime, hydro has yielded more upfront cost (learning, materials, physical effort) but once i came to understand the whats and whys, that upfront effort has yielded a hell of a lot less involvement on my part.

 

[Rootsruler]

yeah, that's my one rub with hydro, getting it to a state of equilibrium then not fucking with it too much aside from ongoing maintenance. can't really trust a buddy or babysitter to handle that kind of work when you're away though. hell, i had to fly out of town for work last year late in flower on my last run. left a simple 30 step instruction set for refilling the res for my ol lady to follow lol. was still biting nails hoping she did it right, but she managed fine then i fucked up it all up with a timer incident guess that proves your point haha

i never did good with soil, tbh. at least not with cannabis. just about anything else i can grow in it, even supposedly "hard to grow" plant varieties. cannabis, though... not so much. ime, hydro has yielded more upfront cost (learning, materials, physical effort) but once i came to understand the whats and whys, that upfront effort has yielded a hell of a lot less involvement on my part.

I always tell newbs that want to go full hydro that they are now committing to being God for those plants. You control almost every component of their livelihood. Fuck one of them up and everything goes out of balance.

I like to break it down to them in zones. Environment and root zone. In dirt, the root zone is pretty much handled so the only thing you really need to worry about is the environment and keeping it within the range you want for the growth level the plant is at. Easy. In hydro you have to chew gum and walk at the same time. Not so easy.

Maybe a better example would be a juggler trying to juggle 30 things at once for hydro.

 

[tobh]

I always tell newbs that want to go full hydro that they are now committing to being God for those plants. You control almost every component of their livelihood. Fuck one of them up and everything goes out of balance.

I like to break it down to them in zones. Environment and root zone. In dirt, the root zone is pretty much handled so the only thing you really need to worry about is the environment and keeping it within the range you want for the growth level the plant is at. Easy. In hydro you have to chew gum and walk at the same time. Not so easy.

Maybe a better example would be a juggler trying to juggle 30 things at once for hydro.

that's a great analogy. then the hardest battle they face is the inevitable overwatering but that's easily correctable once they figure out how to water properly.

 

[Rootsruler]

that's a great analogy. then the hardest battle they face is the inevitable overwatering but that's easily correctable once they figure out how to water properly.

Yup. Learning to water correctly is easy. Learning to create a survivable, water based microbiome is much harder.

 

[tobh]

Yup. Learning to water correctly is easy. Learning to create a survivable, water based microbiome is much harder.

sterile is my cheat code tried the live res route, that was a disaster. went sterile and will never try live again unless i get into like aquaponics or something along those lines. huge digression from the topic at hand, sorry y'all!

 

[Rootsruler]

sterile is my cheat code tried the live res route, that was a disaster. went sterile and will never try live again unless i get into like aquaponics or something along those lines. huge digression from the topic at hand, sorry y'all!

Now ya see....I consider sterile hydro akin to salt based nute programs. Salt based doesn't rely as much on the bacterial and fungal rhizosphere since they are readily available. I see the same thing with sterile hydro. You're not really using bacteria and fungus to break the food down into usable ions.

 

[tobh]

Now ya see....I consider sterile hydro akin to salt based nute programs. Salt based doesn't rely as much on the bacterial and fungal rhizosphere since they are readily available. I see the same thing with sterile hydro. You're not really using bacteria and fungus to break the food down into usable ions.

true that. personally, i wouldn't want to be having fermentation going on with some large volume of water in a hydro system. That just sounds like a smelly, and difficult situation to deal with. Plus, in hydro running salts is just so much cheaper than trying to keep some semblance of a happy biome. when bacteria bloom in large bodies of water it can get out of hand quickly, and thus wreak havoc in all kinds of ways.

 

[Rootsruler]

true that. personally, i wouldn't want to be having fermentation going on with some large volume of water in a hydro system. That just sounds like a smelly, and difficult situation to deal with. Plus, in hydro running salts is just so much cheaper than trying to keep some semblance of a happy biome. when bacteria bloom in large bodies of water it can get out of hand quickly, and thus wreak havoc in all kinds of ways.

Exactly. Why do you want to complicate your grow? Granted, if you have the time and expertise then have at it. You will be handsomely rewarded.

Otherwise, use a method that will get you to harvest. Maximize it then move on to something else that will increase your goals.

 

[Observer]

What you are doing is the way to control all 3. If you want to automate the process, just plug the humidifier into the same timer outlet as the lights.

Overlooked this bit, that's what I did last time run

I'm starting to push my my plants and to do so, vpd has to be right.

 

[pk1]

sterile is my cheat code

agreed

 

[smoke]

Hydro is easy even a cave man can do it. Lol

Ive grown a 4 site rdwc from current culture for the last 10 years. I don't grow live and i don't run sterile. I grow in a style moe termed as "NEITHER". We think part of the reason im able to do it is because every year for the last 10 years i only run 2 grows back to back.

I remember tobh saying to me at the farm that i was either the luckiest grower he new or i have found the answer and i dont know it. We were looking at culture growth and digging deeper before all hell broke out.

We are empty at the moment and plan to start next grow sometime next month

 

[Observer]

Hydro is easy even a cave man can do it. Lol

Ive grown a 4 site rdwc from current culture for the last 10 years. I don't grow live and i don't run sterile. I grow in a style moe termed as neither. We think part of the reason im able to do it is because every year for the last 10 years i only run 2 grows back to back.

I remember tobh saying to me at the farm that i was either the luckiest grower he new or i have found the answer and i dont know it. We were looking at culture growth and digging deeper before all hell broke out.

We are empty at the moment and plan to start next grow sometime next month

I'm intrigued

What would this be called

 

[smoke]

I'm intrigued

What would this be called

So am i, I've bean telling my wife for years that we shouldn't be able to do what we do.

Live, sterile, neither

 

[Observer]

So am i, I've bean telling my wife for years that we shouldn't be able to do what we do.

Live, sterile, neither

Wait

 

[Observer]

from current culture

What