Take The Vpd Poll. How Important Is It?

  • Thread starter ShroomKing
  • Start date
  • Tagged users None

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


  • Total voters
    23
  • Poll closed .
DemonTrich

DemonTrich

6,394
313
vdp is very important. once I added my ultrasonic fogger system to my veg room (9 disc with adjustable speed 80mm fan), I saw an immediate growth spurt with in the 1st week alone. I match it to my room temps, 82* and 75% rh. my rh before the fogger was 50% tops.

shroom king, your vdp chart is a bit different that my chart (below). orange being the target ratios. maybe the chart is stretched out for ease of viewing???

in flower I don't go over 55/60 tops no matter what the vdp chart says. but I have huge air movement in both rooms.
 
VDP chart
Y

YaBuddy321

123
28
vdp is very important. once I added my ultrasonic fogger system to my veg room (9 disc with adjustable speed 80mm fan), I saw an immediate growth spurt with in the 1st week alone. I match it to my room temps, 82* and 75% rh. my rh before the fogger was 50% tops.

shroom king, your vdp chart is a bit different that my chart (below). orange being the target ratios. maybe the chart is stretched out for ease of viewing???

in flower I don't go over 55/60 tops no matter what the vdp chart says. but I have huge air movement in both rooms.
Do you have a link for that fogger?
 
DemonTrich

DemonTrich

6,394
313
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.

there may be some truth to that. I know mj is different, but what about the tropical rain forests? rain forests have some of the greatest and most dense forests in the world. their running 90*+ and 100% rh day after day after day.
 
ShroomKing

ShroomKing

Best of luck. Peace
3,127
263
Great replies everyone.

I personally have no control over VPD parameters in my grow room.
My flower tent holds steady at 82*f with 40-50% rh. I don't ever really have any issues. But I do get a few crispy leaves towards end of flower.
My vote. ...It means nothing....MuHaHaHa!
 
sixstring

sixstring

7,079
313
You mind taking a look at some pics?
Not at all.point me to your thread so we dont clutter this one.

vdp is very important. once I added my ultrasonic fogger system to my veg room (9 disc with adjustable speed 80mm fan), I saw an immediate growth spurt with in the 1st week alone. I match it to my room temps, 82* and 75% rh. my rh before the fogger was 50% tops.

shroom king, your vdp chart is a bit different that my chart (below). orange being the target ratios. maybe the chart is stretched out for ease of viewing???

in flower I don't go over 55/60 tops no matter what the vdp chart says. but I have huge air movement in both rooms.
I always said there should be different charts for different plant species
.why would a vpd chart designed for lettuce be useful for pot?
So i would question where the charts came from and who made them. I have seen a few dif ones out there
 
shemshemet

shemshemet

623
143
It definitely has merit, but I disagree with the ideal charts. As already pointed out in this thread there are at least 2 different charts. Each species is different and with cannabis varities and taxonomy all over the place, it would be very difficult to standardize at this point. Regional heritages of the variety may be able to be used, but I am not so sure the work has been done.
 
Mudskipper

Mudskipper

41
18
I know mj is different, but what about the tropical rain forests? rain forests have some of the greatest and most dense forests in the world. their running 90*+ and 100% rh day after day after day.

There's so much foliage because of the humidity. Rainforests typically don't have deep massive root systems. The soil there is very alive, teeming w/ microbes and mycorrhiza. It's also why so many of the plants have evolved to have massive leaves etc.
 
DemonTrich

DemonTrich

6,394
313
There's so much foliage because of the humidity. Rainforests typically don't have deep massive root systems. The soil there is very alive, teeming w/ microbes and mycorrhiza. It's also why so many of the plants have evolved to have massive leaves etc.


exactly why vdp is critical for a grower.

my sfv og x dmt has super huge fanleaves, 10" or greater fingers, in 4.7g pots currently in veg. most of us also inoculate our soil and add myco as well.
 
shemshemet

shemshemet

623
143
There are many factors in determining "ideal plant growth" and in cannabis growing especially, this becomes extremely subjective.

There are odd relationships between photosynthetic rates and secondary plant metabolism. This important because that basically boils down to this:

Photosynthetic rates and resin production are not one in the same. Photosynthetic rates build plant material; including cell growth, multiplication, etc.

It is very possible increasing your rates and therefore yield, can take away from resin production.

But none of this has been studied in any detail with cannabis.....

@ShroomKing really nice looking!

I don't think you have to fix much
 
DemonTrich

DemonTrich

6,394
313
Vpd I would never spray that shit on my plants, sounds toxic.


who is telling anyone to spray anything on their plants? you can raise your rh with a fogger system, which moistens the air, not foliar sprays the plants.

I don't worry about vdp in flower, veg only. I run max 60%, ideally 50%-60 any given time in flower.
 

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