Drying and Curing using vpd

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g4sho

Well-Known Member
raggyb said:
You're making me think that even if I can't afford to get my drying temps down below 66F (edit) I should be trying to increase my atmosphere's rH above 60% to target a vpd of .8kpa instead of targeting 60% rH. It would seem I would probably need to increase my atmosphere's rH whereas what you are doing is lowering your rH because yours are in a wine cooler. I'd still lose terpenes but maybe minimize their losses and maximize chlorophyll losses if the dry completes in 9 days in other words not too slow not too fast. I take it you keep the door shut and don't swap in O2 in while you are drying? Is that right?
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Yes for the most part, I do not intentionally open the door to exchange air. But the door gets opened to check for moisture level activity with the moisture meter, and for general observation. And I did flip the trays from front to back to insure more balanced drying once during the 9 day cycle. The two trays with cutouts for dehumidifier, I just moved the flower that was in the front to the back and vise versa. This may have been totally unnecessary, but I am anal sometimes. That temp should be below 70 if possible, because terpene preservation is one of the priorities of this method. The Koolatron like the Cannatrol, provides a controlled enviroment which would really be hard to achieve in a tent or a room(unless you can completely seal it). That is the main take away. And what I present here is for the purpose of using the Koolatron as a tool, not for any other situation even tho it may apply.
 
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g4sho

Well-Known Member
raggyb said:
You're making me think that even if I can't afford to get my drying temps down below 66F (edit) I should be trying to increase my atmosphere's rH above 60% to target a vpd of .8kpa instead of targeting 60% rH. It would seem I would probably need to increase my atmosphere's rH whereas what you are doing is lowering your rH because yours are in a wine cooler. I'd still lose terpenes but maybe minimize their losses and maximize chlorophyll losses if the dry completes in 9 days in other words not too slow not too fast. I take it you keep the door shut and don't swap in O2 in while you are drying? Is that right?
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Here are some tools I use to calculate for my environment.
www.dimluxlighting.com

Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights

Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...
www.dimluxlighting.com www.dimluxlighting.com

Dew Point Calculator

Dew Point Calculator is a web resource created by the Image Permanence Institute to help express and visualize the relationship between temperature, relative humidity and dew point.
www.dpcalc.org
 
raggyb

raggyb

Well-Known Member
g4sho said:
Here are some tools I use to calculate for my environment.
www.dimluxlighting.com

Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights

Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...
www.dimluxlighting.com www.dimluxlighting.com

Dew Point Calculator

Dew Point Calculator is a web resource created by the Image Permanence Institute to help express and visualize the relationship between temperature, relative humidity and dew point.
www.dpcalc.org
Click to expand...
very helpful. thanks
 
raggyb

raggyb

Well-Known Member
g4sho said:
Here are some tools I use to calculate for my environment.
www.dimluxlighting.com

Vapor Pressure Deficit VPD Calculator - Dimlux Lighting - The Best Grow Lights

Vapor Pressure DeficitCalculator Calculate both Room VPD and Leaf VPD automatically Just enter the value below to generate the VPD values for your room and your plants. You’ll need to know the room’s temperature, relative humidity, and the plant’s temperature. We recommend calibrating your...
www.dimluxlighting.com www.dimluxlighting.com

Dew Point Calculator

Dew Point Calculator is a web resource created by the Image Permanence Institute to help express and visualize the relationship between temperature, relative humidity and dew point.
www.dpcalc.org
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Using that info, if 0.8 vpd is desired,
at 80F I would want 77% rH, at 70F 68%, and at 60F 55%.

And then for curing we don't want to lose any more moisture I imagine, so target 1.0 vpd:
80F:72% , 70F:60% ,60F:44%
or a little higher % to be on the safe side, < 1 vpd
44% at 60F is a surprise to me compared to what they always say.

Hard to control, but this is eye opening and makes sense to me. So theoretically if dry chamber is at 70F and 68%, the buds would still be giving moisture to the air and drying down to less than 68% say the target 62%. I'm not totally convincing myself this wont have issues like mold but maybe not. It becomes harder to control rH in a chamber and provide airflow at the same time. So if for some reason we need light airflow while drying like they always say this becomes more tricky. I get that in your Kooltron the drying buds release water to the air and then you need to dehydrate so you won't need to raise T above 66. That's totally cool. I guess my takeaway now is in my cheaper arrangement I will monitor T and H and try to keep the rH a little higher than I used to think I should which is not a problem like day 1-4 but maybe too low day 5 and on depending...
 
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g4sho

Well-Known Member
raggyb said:
Using that info, if 0.8 vpd is desired,
at 80F I would want 77% rH, at 70F 68%, and at 60F 55%.

And then for curing we don't want to lose any more moisture I imagine, so target 1.0 vpd:
80F:72% , 70F:60% ,60F:44%
or a little higher % to be on the safe side, < 1 vpd
44% at 60F is a surprise to me compared to what they always say.

Hard to control, but this is eye opening and makes sense to me. So theoretically if dry chamber is at 70F and 68%, the buds would still be giving moisture to the air and drying down to less than 68% say the target 62%. I'm not totally convincing myself this wont have issues like mold but maybe not. It becomes harder to control rH in a chamber and provide airflow at the same time. So if for some reason we need light airflow while drying like they always say this becomes more tricky. I get that in your Kooltron the drying buds release water to the air and then you need to dehydrate so you won't need to raise T above 66. That's totally cool. I guess my takeaway now is in my cheaper arrangement I will monitor T and H and try to keep the rH a little higher than I used to think I should which is not a problem like day 1-4 but maybe too low day 5 and on depending...
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Good Luck! But just an f.y.i. and you may already know this, but the higher the vpd the more moisture is pulled out the plant, the lower the vpd the least amount of moisture is pulled out the plant(in the same given time period) in drying.
 
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raggyb

raggyb

Well-Known Member
g4sho said:
Good Luck! But just an f.y.i. and you may already know this, but the higher the vpd the more moisture is pulled out the plant, the lower the vpd the least amount of moisture is pulled out the plant(in the same given time period) in drying.
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Oh thank you so much for correcting me! For some reason I was saying 1.0 vpd would be total saturation. I should have meant to say about 0 vpd is what you want in cure.
 
raggyb

raggyb

Well-Known Member
So here was error. It still makes sense to me that if 0.8 vpd is desired, then
at 80F I would want 77% rH, at 70F 68%, and at 60F 55%.

But for curing, when you want air to accept no moisture from bud, you might think you want 0 vpd. But yeah, that is at 100% rH which sounds a little crazy. Then no matter what temperature, you want 100% rH. Seems like mold would format 100%. Maybe true in theory with pure atmosphere but we're not in a pristine no mold spore atmosphere. So I'm not sure what vpd is safe for no mold. Say you shot for 0.5 vpd in cure,

80F:86% , 70F:80% ,60F:72%

But 0.5 vpd is purely a guess. I've got a jar curing now at 80F and 68% rH and it certainly is not growing mold. Note it was brought down to 62% already but then the room got humid and brought the air in the jar back up. I suppose if I wanted I could find a way to bump it up some percents. I'm not sure what good it would do but maybe it eliminates more chlorophyll.
 
G

g4sho

Well-Known Member
raggyb said:
So here was error. It still makes sense to me that if 0.8 vpd is desired, then
at 80F I would want 77% rH, at 70F 68%, and at 60F 55%.

But for curing, when you want air to accept no moisture from bud, you might think you want 0 vpd. But yeah, that is at 100% rH which sounds a little crazy. Then no matter what temperature, you want 100% rH. Seems like mold would format 100%. Maybe true in theory with pure atmosphere but we're not in a pristine no mold spore atmosphere. So I'm not sure what vpd is safe for no mold. Say you shot for 0.5 vpd in cure,

80F:86% , 70F:80% ,60F:72%

But 0.5 vpd is purely a guess. I've got a jar curing now at 80F and 68% rH and it certainly is not growing mold. Note it was brought down to 62% already but then the room got humid and brought the air in the jar back up. I suppose if I wanted I could find a way to bump it up some percents. I'm not sure what good it would do but maybe it eliminates more chlorophyll.
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I am not sure what your goal is but If you have had good luck with traditional drying and curing, and not planning on using a wine cooler, why are you changing your method? I read thru your plan of action, and I was not sure what you are trying to accomplish. But I will only tell you what I believe to be the case as far as vpd goes. If you set a vpd at .5kpa there will probably be no moisture taking out of the plant due to no difference in vapor pressure. At .6 it is very slow but should have some movement. But the longer there is water activity in the plant whether in dry or cure, enables the opportunity for disease. So take that with a grain of salt. But thats all I have for you in reference to that. This thread is about me documenting vpd drying and curing with the Koolatron, so I would like to keep it on topic. Like I said wish you the best of luck.
 
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raggyb

raggyb

Well-Known Member
g4sho said:
I am not sure what your goal is but If you have had good luck with traditional drying and curing, and not planning on using a wine cooler, why are you changing your method? I read thru your plan of action, and I was not sure what you are trying to accomplish. But I will only tell you what I believe to be the case as far as vpd goes. If you set a vpd at .5kpa there will probably be no moisture taking out of the plant due to no difference in vapor pressure. At .6 it is very slow but should have some movement. But the longer there is water activity in the plant whether in dry or cure, enables the opportunity for disease. So take that with a grain of salt. But thats all I have for you in reference to that. This thread is about me documenting vpd drying and curing with the Koolatron, so I would like to keep it on topic. Like I said wish you the best of luck.
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Sorry, It sounds like I be irritating you. Better than a dead thread though, right? Anyhow, I'm not changing my methods, I'm improving them on my limited budget but can do attitude. In my case my main takeaway from what you described is that I can target vpd during drying, instead of rH. I cure and do well enough but could always do better and even though my cures have got pretty well I don't know the reasons why exactly it works well and your vpd concepts got me more important understanding. Until now I've only heard vpd talking about growing and never about drying so thank you for bringing that to my attention. Like you I want to preserve terps and still have them, but not as many as you, homey. I monitor T and rH religiously during the dry, but didn't tie vpd into that. I would thank you though because I'm confirming I'm pretty close to keeping vpd in a range while drying. Now I understand more what is happening and I'm going to try and target vpd more precisely at varying temps and modulating humidity albeit less exactly than you are. Good luck getting some killer flower. Raggy out
 
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g4sho

Well-Known Member
raggyb said:
Sorry, It sounds like I be irritating you. Better than a dead thread though, right? Anyhow, I'm not changing my methods, I'm improving them on my limited budget but can do attitude. In my case my main takeaway from what you described is that I can target vpd during drying, instead of rH. I cure and do well enough but could always do better and even though my cures have got pretty well I don't know the reasons why exactly it works well and your vpd concepts got me more important understanding. Until now I've only heard vpd talking about growing and never about drying so thank you for bringing that to my attention. Like you I want to preserve terps and still have them, but not as many as you, homey. I monitor T and rH religiously during the dry, but didn't tie vpd into that. I would thank you though because I'm confirming I'm pretty close to keeping vpd in a range while drying. Now I understand more what is happening and I'm going to try and target vpd more precisely at varying temps and modulating humidity albeit less exactly than you are. Good luck getting some killer flower. Raggy out
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No irritation, don't know why you felt that way. Answered your questions best I could. But did not want the thread to go away from its intended purpose. There are plenty other threads that discuss traditional curing and drying. The very first comments on page one clearly states what this threads purpose was. And you will always be able to refer back to this thread, when or if you ever splurge and get the equipment listed. Take my word for it, you will be glad you did. So take care and keep learning and growing.
 
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NutterDeep

New Member
g4sho said:
Set and forget. But there is nothing to stop you from sloping it down over a period of time. I just don't think it is necessary as it will cycle between .7 and .8kpa with the vpd set at .7kpa setting for cure. Temp should be always lower than 69 I prefer 64 to 66F.
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So starting off vpd is set to .8kpa and just the controller do it thing?
 
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g4sho

Well-Known Member
NutterDeep said:
So starting off vpd is set to .8kpa and just the controller do it thing?
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Thats the ticket. Make sure you calibrate your temp/humid probe to your koolatron temp. Once you get going be great if you post your min/max data screenshots so we can see if it is consistent like mine was. I also used two different hygrometers to verify humidity calibration for the ac infinity.
 
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g4sho

Well-Known Member
DriverMain said:
Is there an EU version of the UIC adapter from AC or how do you connect the dehum. to the ACInfinity (with an EU plug)?
Thanks a lot!
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I am not sure, but as mentioned earlier, If you don't already own the ac infinity 69 pro, you can opt for the 79 pro which has two controller outlets built in. So you would not need the uic adapter. And its a little cheaper also. Here is the webpage that should help with your question.

International Orders

acinfinity.com acinfinity.com
 
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FmSwayze

FmSwayze

Well-Known Member
g4sho said:
Just some information I found in reference to the $1600 machine we are trying to emulate. Seems vpd is indeed the tool that unit is controlling also, the same as we are doing here.
terpenesandtesting.com

How Cool is Your Cure? - Terpenes and Testing Magazine

Cannatrol Helps Cultivators Establish Command Over The Dry Cure Process When you walk through a field of something like wildflowers, or desert sage, or cannabis, unless you’re lacking in olfaction, you can’t help but notice and inhale the honeyed fragrances wafting into your nose. While this is...
terpenesandtesting.com terpenesandtesting.com
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I think the inventor used dew point of 56 by default. Thanks for this thread btw. How is the cure coming along?
 
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g4sho

Well-Known Member
princessonthebeach69 said:
Do you enjoy the results? Do you think it was worth the effort?
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Yes, it made it almost fool proof, no need to do alot of guessing. And especially if you don't have full control of your environment. I still have some jarred up, it stays fresh at room temp around 68.
FmSwayze said:
I think the inventor used dew point of 56 by default. Thanks for this thread btw. How is the cure coming along?
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Sorry, I am just seeing this. Cure went great! I still have some left jarred up and it is still viable this many months later. Like I said earlier it takes the guess work out, and is mostly automated. This is how I dry from now own.
 
OgTigerKing

OgTigerKing

Member
Stomatal opening is controlled by starch content after harvest. How do you factor that in.

The plant is trying to use all it's energy before the next daylight, which it has predicted based on past daylight patterns, but will never come. So it starts pulling apart proteins to obtain its energy at the first moment of increased night length (harvest) .

How do you factor that in? If Vpd charts are only relative to light dependent reactions, stomatal opening not cuticular or lenticular transpiration.
 
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princessonthebeach69

New Member
OgTigerKing said:
Stomatal opening is controlled by starch content after harvest. How do you factor that in.

The plant is trying to use all it's energy before the next daylight, which it has predicted based on past daylight patterns, but will never come. So it starts pulling apart proteins to obtain its energy at the first moment of increased night length (harvest) .

How do you factor that in? If Vpd charts are only relative to light dependent reactions, stomatal opening not cuticular or lenticular transpiration.
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Do you account for it when you dry/cure?
 
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