Take The Vpd Poll. How Important Is It?

ShroomKing · Nov 20, 2015

Let's hear what you think about VPD , or Vapor Pressure Differential , and it's importance to YOUR growing style. Do you follow it? Do you care? Has it changed your game? Let's hear it!

Everyone is entitled to their own opinions. Let's keep the heckling down to a minimum and keep our minds open.

Peace

3N1GM4 · Nov 20, 2015

The question might as well be "how important is quantum physics?" Because I have no idea what pressure humidity and temp have to do with each other

ShroomKing · Nov 20, 2015

3N1GM4 said:
The question might as well be "how important is quantum physics?" Because I have no idea what pressure humidity and temp have to do with each other

Something about how much moisture the air holds at certain temperatures and how this effects a plants respiratory system. And by controlling these factors you can have optimal growth ability, or somesuch.

sixstring · Nov 20, 2015

I voted it means nothing :)

sixstring · Nov 20, 2015

I mean if you want growth so fast that the leaves grow faster than the thc can cover the leaf then vpd is the way to go.but ime lower rh beings on more resin.of course thats just my own observation lol

cocoJoe · Nov 20, 2015

sixstring said:
I mean if you want growth so fast that the leaves grow faster than the thc can cover the leaf then vpd is the way to go.but ime lower rh beings on more resin.of course thats just my own observation lol

I concur..

ShroomKing · Nov 20, 2015

sixstring said:
I voted it means nothing :)

cocoJoe said:
I concur..

Ive seen users claim vpd parameters were why a new users plants were showing deficiency, in the infirmary threads.

Is this even possible?

fishwhistle · Nov 20, 2015

I do follow it somewhat my veg is 60-65 right now,in flower im usually 55-60 and dropping the last few weeks to around 50.Is it a gamechanger?I dont know,i voted i just want to smoke weed,lol.
I think everyones setup,geographical location,grow style etc dictates what works best for them,here its dry and cool in winter and dry and hot in summer so i think its one little thing that helps a bit in the overall picture.

Mudskipper · Nov 20, 2015

ShroomKing said:
Is this even possible?

No

3N1GM4 said:
The question might as well be "how important is quantum physics?" Because I have no idea what pressure humidity and temp have to do with each other

Wet Bulb https://en.wikipedia.org/wiki/Wet-bulb_temperature

CelticEBE · Nov 20, 2015

It depends on what you are trying to achieve. Commercial growers who are looking for max weight by using CO2 and pushing the plants to produce as much as possible, should pay close attention to hitting the sweet spot on temps and rh. Whereas if you are looking for a higher quality product it's not nearly as important.

I also think that things are very strain dependent. A strain that has it's origins from the Hindu Kush region is going to react a lot different than an Equatorial Sativa. It's all about dialing things in and knowing what your plants like.

ClassV · Nov 20, 2015

I'm a novice grower, and weather caused significant swings in RH and temps over several weeks while vegging my current grow. I definitely noticed a difference in how they feed and respond at 75% RH as opposed to 45 %. Nothing drastic, but noticable.

There does seem to be a relationship between transpiration, RH, temps, and the plant's processes. Dunno if the values listed in the VPD chart accurately describe the relationships though.

sixstring · Nov 20, 2015

ShroomKing said:
Ive seen users claim vpd parameters were why a new users plants were showing deficiency, in the infirmary threads.

Is this even possible?

i think it could def be a reason for newer growers to have major problems.if the rh gets too high they have one set of probs and when it gets real low they have totally dif probs.low rh will def make a new grower work hard to keep plants from locking out nutes or burning the piss out of them,even more so if they are following a feed chart lol.and i do think higher rh in the 60-75%range can make a shitty grower look much better.that is until the bugs and molds decide its a perfect spot to hang out when it creeps into the 80% range hahaha.but i cant say i ever saw a grower with problems post pics and say,oh fuck dude those plants are def not happy cause the vpd is off.then again most times new growers wont give all the important info needed to get proper help without being proded with multiple questions.

Mudskipper · Nov 21, 2015

The drier the air the better, as long as the temp is controlled. Higher humidity means the less the plant needs to search for moisture w/ its roots because it's absorbing what it needs(h2o wise) thru its leaves. End all means smaller flowers.

shemshemet · Nov 21, 2015

@Mudskipper I'm not going to claim statements of higher/lower humidity are wrong, but I will correct your statement.

Plants don't typically absorb water through their leaves. What may be happening is a lack of transpiration. Where you're plants are taking longer get rid of the h2o inside them. Water travels from roots to shoots to leaves and out of the stomata due to transpiration (water gas in the leaf moves out of the leaf).

Evapotranspiration is determined mostly by....well you guessed it: VPD

YaBuddy321 · Nov 21, 2015

Can a bad VPD pressure cause decencies ? Droopy leaves and yellowing?

MidwestToker · Nov 21, 2015

Just some observations from experience. If I put my hygrometer in the canopy with the foliage I always get a reading 5-15 % higher than when it's just sitting around in the room.

sixstring · Nov 21, 2015

YaBuddy321 said:
Can a bad VPD pressure cause decencies ? Droopy leaves and yellowing?

Yes it can.even a really high rh can make plants droop.
But i want to correct something that was just posted.leaves can and will take in water as well as expell it,thats partly why its called transpire and not perspire like people do when they sweat.foliar feeds would not work as well if the plant didnt take in water at the leaf surface.

YaBuddy321 · Nov 21, 2015

I have a temp of 75 with a RH of 30%. That is in the red on the chart you think that is causing my issues? I bought a big humidifier but it only raised it from 15% to between 30% and 40% RH. @sixstring thanks

sixstring · Nov 21, 2015

YaBuddy321 said:
I have a temp of 75 with a RH of 30%. That is in the red on the chart you think that is causing my issues? I bought a big humidifier but it only raised it from 15% to between 30% and 40% RH. @sixstring thanks

It can definitely make problems worse if you run those numbers and dont have all your ducks in a row.but those # you posted are right in my sweet spot.75 to 78f and 30 to 40%rh.
Im at 78f and 32%rh right now just slammed my ladies with 800ppm (1.6ec) of jacks bloom booster till it was just barely pissin out the pots and my ladies all said Aaaahhhh,thanks dad. :)

sixstring · Nov 21, 2015

YaBuddy321 said:
I have a temp of 75 with a RH of 30%. That is in the red on the chart you think that is causing my issues? I bought a big humidifier but it only raised it from 15% to between 30% and 40% RH. @sixstring thanks

But i dont know what kind of issues you have.sounds like you need 2x bigger humidifier.run it at 50 to 60% and plants will be much easier to correct.at 76f that is.gl

Take The Vpd Poll. How Important Is It?

Take The Vpd Poll. How Important Is It?

How important is (VPD) Vapor Pressure Differential in your garden?

Very Important!

It means nothing..........MuHaHaHa!

I just want to smoke weed.

ShroomKing

Best of luck. Peace

3N1GM4

ShroomKing

Best of luck. Peace

sixstring

sixstring

cocoJoe

ShroomKing

Best of luck. Peace

fishwhistle

Mudskipper

CelticEBE

ClassV

sixstring

Mudskipper

shemshemet

YaBuddy321

MidwestToker

sixstring

YaBuddy321

sixstring

sixstring

Take The Vpd Poll. How Important Is It?

Take The Vpd Poll. How Important Is It?

How important is (VPD) Vapor Pressure Differential in your garden?

Very Important!

It means nothing..........MuHaHaHa!

I just want to smoke weed.

ShroomKing

Best of luck. Peace

3N1GM4

ShroomKing

Best of luck. Peace

sixstring

sixstring

cocoJoe

ShroomKing

Best of luck. Peace

fishwhistle

Mudskipper

CelticEBE

ClassV

sixstring

Mudskipper

shemshemet

YaBuddy321

MidwestToker

sixstring

YaBuddy321

sixstring

sixstring

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