Understanding VPD chart.

Helmut79

Helmut79

Well-Known Member
I made a new thread as I have gotten so many PM's lately by so many forum members who want to see more threads from me.

I am now going to figure out what is a VPD chart and how can it be applied and where.

If you have something helpful and interesting to say, please talk.

I am probably going to post again soon.
 
Dr. Who

Dr. Who

Well-Known Member
Really?

Vapor Pressure Deficit.

I don't use it as it sits. I like to manipulate the plants up-take by doing less RH then optimal. This practice is something you have to learn to do, or risk overfeeding......

Now as far as the use of GAS (Co2). The VPD is directly into play! It should be followed exactly when gassing with the required higher temps to make the gas the the most effective.

If your running at 70 F. The optimal RH factor is kind of high to me. PM can become a problem...You need to understand that by lowering it. You increase up-take. This increases nutrients to the plant. Increasing your chances of problems..

The environmental balance of your room. Is critical to final results. Holding tight those values, so they don'y vary much at all. Make for consistency in results. Being consistent, allows you to work for reaching plant potentials.

Growing for potentials. Is the ultimate form of cannabis growing, in my opinion.
 
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natureboygrower

natureboygrower

Well-Known Member
Dr. Who said:
Really?

Vapor Pressure Deficit.

I don't use it as it sits. I like to manipulate the plants up-take by doing less RH then optimal. This practice is something you have to learn to do, or risk overfeeding......

Now as far as the use of GAS (Co2). The VPD is directly into play! It should be followed exactly when gassing with the required higher temps to make the gas the the most effective.

If your running at 70 F. The optimal RH factor is kind of high to me. PM can become a problem...
Click to expand...
yeah ,i noticed that too.first 2 weeks of flower=65%-75% rh?? yikes
 
Helmut79

Helmut79

Well-Known Member
Dr. Who said:
I don't use it as it sits. I like to manipulate the plants up-take by doing less RH then optimal. This practice is something you have to learn to do, or risk overfeeding......

Now as far as the use of GAS (Co2). The VPD is directly into play! It should be followed exactly when gassing with the required higher temps to make the gas the the most effective.

If your running at 70 F. The optimal RH factor is kind of high to me. PM can become a problem...You need to understand that by lowering it. You increase up-take. This increases nutrients to the plant. Increasing your chances of problems..

The environmental balance of your room. Is critical to final results. Holding tight those values, so they don'y vary much at all. Make for consistency in results. Being consistent, allows you to work for reaching plant potentials.

Growing for potentials. Is the ultimate form of cannabis growing, in my opinion.
Click to expand...
Exactly what I was thinking about. I can see the chart and the "golden zone" at which temp and rh would be best for the plant, but how can it be applied when gassing with 1100ppm of CO2?

Who made the chart and to what extent can we rely on it?
 
Jaybodankly

Jaybodankly

Well-Known Member
The chart as I understand is a function of stomata. At a given temp and range of humidity the stomata are optimum and fully open able to easily take in CO2. It is like having the right fuel/air mix in a carburetor.
 
Dr. Who

Dr. Who

Well-Known Member
Helmut79 said:
Exactly what I was thinking about. I can see the chart and the "golden zone" at which temp and rh would be best for the plant, but how can it be applied when gassing with 1100ppm of CO2?

Who made the chart and to what extent can we rely on it?
Click to expand...
How to apply?

Use a ppm control switch set to 1100 ppm Co2

Use an environmental controller. Set it to 88F and 80% RH.

When the controller's set point is reached. The gas shuts off. The exhaust turns on, as does the cooling. It draws out the air and adds new cool air.
At another set point. The controller shuts off the exhaust/cooling. Turns on the gas, and holds it at it's 1100 ppm till the whole thing starts over. This allows for the best effective use of the available co2 by the plant.

Going over 1300 ppm is flat out a waste. The amount of light intensity to actually use the ever increasing need of it by the plant (on a bell curve) is basically very hard to do as you need to deliver over 80,000 lux of light......To reach the ability to use even that 1200 to 1300 ppm. Your going to need to run 1400 K w of HID.
There are formula's to know where your at but, basically put. You need to supply 1000 w of HID to run to that 1100-1200 ppm. Read Ed Rosenthals Marijuana growers handbook - pages 132 - 133.
 
ttystikk

ttystikk

Well-Known Member
Dr. Who said:
How to apply?

Use a ppm control switch set to 1100 ppm Co2

Use an environmental controller. Set it to 88F and 80% RH.

When the controller's set point is reached. The gas shuts off. The exhaust turns on, as does the cooling. It draws out the air and adds new cool air.
At another set point. The controller shuts off the exhaust/cooling. Turns on the gas, and holds it at it's 1100 ppm till the whole thing starts over. This allows for the best effective use of the available co2 by the plant.

Going over 1300 ppm is flat out a waste. The amount of light intensity to actually use the ever increasing need of it by the plant (on a bell curve) is basically very hard to do as you need to deliver over 80,000 lux of light......To reach the ability to use even that 1200 to 1300 ppm. Your going to need to run 1400 K w of HID.
There are formula's to know where your at but, basically put. You need to supply 1000 w of HID to run to that 1100-1200 ppm. Read Ed Rosenthals Marijuana growers handbook - pages 132 - 133.
Click to expand...
LED lighting has the potential to do it.

I know, I've done it.
 
Dr. Who

Dr. Who

Well-Known Member
ttystikk said:
LED lighting has the potential to do it.

I know, I've done it.
Click to expand...
This is true!

But those of us growing out tall plants.. Get better results from HID for overall penetration....... I have to grow tall plants or suffer #'s problems.
I really hate that the state controls me that way.

I would change over in a flat ass minute, if I could run the plant #'s to take advantage of COB's. My 1K's have 400w MV's suspened as it is. Heat is a cooling $ issue during summer months (staying within my calculated limits is easy but, still expensive.). I have them set on 6 ft center to center separation, and that keeps lux up for better growth with those tall plants too.
20170127_121427.jpg
 
ttystikk

ttystikk

Well-Known Member
Dr. Who said:
This is true!

But those of us growing out tall plants.. Get better results from HID for overall penetration....... I have to grow tall plants or suffer #'s problems.
I really hate that the state controls me that way.

I would change over in a flat ass minute, if I could run the plant #'s to take advantage of COB's. My 1K's have 400w MV's suspened as it is. Heat is a cooling $ issue during summer months (staying within my calculated limits is easy but, still expensive.). I have them set on 6 ft center to center separation, and that keeps lux up for better growth with those tall plants too.
View attachment 4046644
Click to expand...
Ummmm no.
20161110_235620.jpg
 
Dr. Who

Dr. Who

Well-Known Member
ttystikk said:
Ummmm no.
View attachment 4046655
Click to expand...
Your not growing a traditional style......Your supplying a flat.....Is the lighting on the ceiling also? Any lighting source below ceiling? Or vertical lighting?

What goals are you reaching with that method.......To me yield is not my focus. It is an end factor but, not a focus point. I also understand your set up too.....

In speaking with some of the new corporate level growers. Attempting to lic. up in the state. The use of COB is not going to fill their bill by plant size limitations of the lighting.
Their going HID...
 
ttystikk

ttystikk

Well-Known Member
Dr. Who said:
Your not growing a traditional style......Your supplying a flat.....Is the lighting on the ceiling also? Any lighting source below ceiling? Or vertical lighting?

What goals are you reaching with that method.......To me yield is not my focus. It is an end factor but, not a focus point. I also understand your set up too.....

In speaking with some of the new corporate level growers. Attempting to lic. up in the state. The use of COB is not going to fill their bill by plant size limitations of the lighting.
Their going HID...
Click to expand...
The lights are beside the plants, to the left.

LED would definitely serve their needs, many utilities would assist with the up front costs and anyone who says that LED can't 'penetrate' as well as HID lighting is optically impotent, lol

I'm quite sure they didn't not consider all the available options on the market or there were additional limitations not discussed.
 
MichiganMedGrower

MichiganMedGrower

Well-Known Member
ttystikk said:
The lights are beside the plants, to the left.

LED would definitely serve their needs, many utilities would assist with the up front costs and anyone who says that LED can't 'penetrate' as well as HID lighting is optically impotent, lol

I'm quite sure they didn't not consider all the available options on the market or there were additional limitations not discussed.
Click to expand...

Lol. You're quite sure you are pretending to know stuff.
 
Dr. Who

Dr. Who

Well-Known Member
ttystikk said:
The lights are beside the plants, to the left.

LED would definitely serve their needs, many utilities would assist with the up front costs and anyone who says that LED can't 'penetrate' as well as HID lighting is optically impotent, lol

I'm quite sure they didn't not consider all the available options on the market or there were additional limitations not discussed.
Click to expand...
*RESPECT* for you and your grows. To be sure!

But I still have to side with the "Not enough for me" guys and COB LED vs. tall plants and effective square inverse law......The fucking starting cost is getting insane too.... But, that's totally a different thread.

Cob led's are stated to be great for compact area's.... I agree. They have too much wasted green banding that is fairly useless to us growers.

Do they work, yes.
Do they work well, yes.
Do they work for taller plants, in a spread out area. Not well enough for me.

I understand this is a hot topic. I'll still stand with Odin on it though..... Please use what works well for you.
 
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