VPD vs. humidity?
- Thread starter soulshine
- Start date
Wastei
Well-Known Member
Having VPD in check is only one of the important parameters for optimal growth. The plants will tell you what's optimal at the end of the day but saying following optimal VPD is stupid is laughable at best.
People who say "they never experience any problems" don't really work to optimize and each to their own. A plant will grow in subpar conditions. I on the other hand need to grow as potent medicine as possible since I use my herb medicinally.
If I were to rug my shoulders with knowingly having my parameters out of range I'm not doing the best job I possibly can do. Some just grow for fun and that's fine to, each to their own!
People who say "they never experience any problems" don't really work to optimize and each to their own. A plant will grow in subpar conditions. I on the other hand need to grow as potent medicine as possible since I use my herb medicinally.
If I were to rug my shoulders with knowingly having my parameters out of range I'm not doing the best job I possibly can do. Some just grow for fun and that's fine to, each to their own!
Porky82
Well-Known Member
So a measurement that was only thought up as a sales point is now somehow seemingly important?
It's only been around since 2017!
Who pissed in your corn flakes? You can call me names all you want. I really don’t give a
. I grow because I enjoy it and I don’t need some holier than thoe telling me that I’m not doing it to their standards. So you do what you want and I’ll do whatever I choose. My grow my choice. CL
Not to be that guy or anything but this made me bust out laughing.. another weird mental image.. this time of you caressing a grow tent while demanding respect for your choices
drugs yo
Some times you gotta know your audience.. it’s clear Cap N Pork don’t care about VPD at all, not even a little bit, and may even be slightly hostile toward it. (Which is unsurprising considering how many gimmicks and fads were sold as the key, especially in growing cannabis, only to fall apart down the road)
It’s been explained and they still have no interest. Fair enough. Those who do care can ask questions, but you’re probably not gonna convince a couple guys that have been around this long if they don’t want to be convinced.
Like I said originally.. it’s a perfectionist measurement.. Like the guy that completes the video game with 100% versus the guy that just wants to have fun. There’s room for everyone to reach the end.
It’s been explained and they still have no interest. Fair enough. Those who do care can ask questions, but you’re probably not gonna convince a couple guys that have been around this long if they don’t want to be convinced.
Like I said originally.. it’s a perfectionist measurement.. Like the guy that completes the video game with 100% versus the guy that just wants to have fun. There’s room for everyone to reach the end.
You just made me burstNot to be that guy or anything but this made me bust out laughing.. another weird mental image.. this time of you caressing a grow tent while demanding respect for your choices
out laughing with your description. Lmao CL. 
none of the most successful longtime growers i know have ever bothered with this. all were growing long before it was ever a thing.
this right here. it was originally dreamt up in part as a way to sell gear.
this right here. it was originally dreamt up in part as a way to sell gear.
Delps8
Well-Known Member
If you were being cheeky, why didn't you say so? ;-)
Another example of one of the drawbacks of digital communication…
Re. VPD - it is as simple or as complex as people want to make it.
Delps8
Well-Known Member
"perfectionist" - isn't that the description given to people who are more detail oriented than the person doing the writing? ;-)
what i find hilarious is the number of folk using the wrong vpd chart. hardly anyone knows the difference between room vpd, leaf vpd, and canopy vpd. it's not only gimmicky, it's the wrong gimmicky.
one company alone has published something like 30 different charts for different cannabis vpd.
Sueet
Well-Known Member
Sorry, I thought it was obvious that it was a backhand statement when I mentioned searching 'til you find a chart that fits you.
As for vpd, I don't worry about it, because I have enough other stuff to worry about, and I live with a great many physical limitations which leaves me in a boat where I'm just happy it's still afloat. I do recognize it could... and maybe even should, be done better than I do it, but at least I'm not a slave to the dispensaries anymore, and my medicine does what I need it to do.
Im gonna disagree with this kind of.. VPD has been known since at least 1936, here’s a link to the first study:
Google Scholar
scholar.google.com
D. B. Anderson was the original proponent however it never caught on. It has an incredibly accurate link between fire and weather. It serves many great purposes that are poorly understood because as we know, it’s not necessary to understand it to grow. It’s not necessary to understand VPD to know that when it’s dry, fires will start, but it will give you a very pinpoint number at which fire will start. It’s a measurement which needs much more study in relation to our environments and as climate change becomes more serious we will need to understand it better.
Plants can grow in any range of conditions. They can barely survive in poor conditions or thrive in perfect conditions. As the climate in an area changes over time, those plants that are barely surviving will only hold on for so long before they can no longer be grown there. Having VPD helps to tell us which plants should be grown where, at a larger scale. This will become more useful as climates change and the old ways and plants of the area become irrelevant.
However.. for your average home grower.. this isn’t really necessary. VPDs importance is lessened with the smaller and more specific your environment is. You don’t need to know the VPD to grow plants at home, you just need to know your environment. Especially with something like cannabis that performs well in a range of climates.
Those in drier environments have already made their changes or adapted to their environments without needing a measurement. Those in wetter climates have adjusted or adapted without needing a measurement. However, if for some reason you found yourself responsible for deciding what crops or plants to grow over a large area, knowing the average VPD would be a useful resource to determine what would grow best in that area.
It can’t be denied though that unscrupulous capitalists have decided to exploit a not well understood measurement to sell people more crap they don’t need. VPD is more useful from a historical/current perspective than a day to day measurement needed be taken by someone with 4 plants in a 5x5 area
I’m gonna stop here because I’m already rambling and I’m only gonna get worse and I made my point
all good. i'm not denying the history. just the use. also the fact that vpd wasn't developed for our industry and is plant specific, and changes with evolving conditions etc etc..
how it's used in the home grow industry is akin to the tunable " full spec" lights. there's far more marketing than delivery.
I agree completely.. It makes me think of a friend who read about it then went and bought a Pulse Pro system for his 2-3 plants he half ass grows every 6 months.
a new local has just spent $2600 cdn on a 2x2 and a 3x3 tent and gawd knows what and killed 3 grows straight. he keeps killing seedlings like it was a business. he's not set up quite right and we can't get him to listen.
myself and a friend have been trying to coach him, i want him to join here but he's paranoid, his wife is super sketching, and i think she managed to sink some good decisions.
Delps8
Well-Known Member
Good of you to clarify.
Digital communication can make it hard to communicate nuance. In this case, the idea of a grower searching until they find the right value didn't strike me as strange, not in the least. I've been an active member of four cannabis sites since I started growing (again) in 2021 and that comment would fit right in including collecting hearts and thumbs up from many growers.
Sorry to hear about the physical limitations and lots of respect for keeping on going through it all.
I agree that it's great to not be beholden to dispensaries - that was a big reason why I started growing cannabis. Here in SoCal, prices are (were) >=$350/ounce. No mas!
Sueet
Well-Known Member
The prices are still that here where I live, and considerably more if you want top shelf.
Delps8
Well-Known Member
Hah, we don't need no stinkin' facts!
It's still "rubbish" and VPD charts are stupid So there!
And "not a well understood measurement to sell people more crap they don't need".
Yes!!! We are victims!!!
And those "capitalists" (evil, evil people doncha know!) are exploiting "measurements" - the bastads!
Think about how evil they are. Take Pulse as an example. They developed a product, made the information about it available to anyone who can access the internet, and then they send things to people when people send them money. Evil, evil, capitalist.
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What wankery…this thread. Not 420's finest.
That poor OP who wasn't clear on low RH vs low VPD and we send the poor SOB this dreck. I'd have to laugh if the fellow never came back.
Let's talk about something less contentious — politics anyone?
