VPD in flowering

[Douglas.Curtis]

Does anyone happen to know the 'maximum' RH you can have with 69-70F temps and still have only one single stem without branching in each flower? Nubs are fine, just no 'branch'.

I crush one of my flowers gently between thumb and 2 fingers and get a frosty pile of flower bits. The single, non-branched, stem easily pulls out of the frosty pile for discard. This is the type of cannabis I prefer, since the amount and complexity of the resin is simply fabulous.

When was the last time you spent a LOT of time taking small hits, simply to sit and savor the complexity of the terpene profile as it lingers on and on and on? When was the last time you licked your lips 45 minutes after smoking a doobie and STILL have enjoyable terpene flavors lingering there?

The presence of stemmy flowers and sERIOUsly boring terp and cannabinoid profiles (in comparison), are major reasons I do not like hot/wet flowers.

 

[Ca++]

All I do is take small hits to taste it. Two or 3 licks, and I'm emptying out bowls, that others want to finish. It's almost like I'm vaping, with the bottom of the bowl often still green. Once it's releasing carbonised dust, I loose interest.

I won't smoke anything so dry it crunches. I would rather wait and humidify it again. Though you can just wet a rolled joint, in a rush.

I like the smell of flowers as they first develop. Mid flower, through to cropping. These are wet smells. Partially because it's sensation and sinus condition. The smell of fresh cut grass is gone when it's dry. The morning air when camping, is all about the RH in the area. Burning the lawn trimmings later, won't give that smell again.

There is no joint that tastes the same to the bottom. It's not the same joint as when you lit it. Not here anyway. Perhaps if everything about your environment is always dry, then it gets no drier. Explaining why you see no change. I'm one that will wet things again.

You can play around with the effects of RH on taste, by smoking in the moisture stream of a humidifier. Even after the driest of weed is burnt, you can inhale moisture along with it, and it tastes fresh. Dry mouth is not helpful, when trying to wash things out of the smoke. The difference is everything.

I should design a proper vape, that puts the RH in place.

 

[Crooked8]

All I do is take small hits to taste it. Two or 3 licks, and I'm emptying out bowls, that others want to finish. It's almost like I'm vaping, with the bottom of the bowl often still green. Once it's releasing carbonised dust, I loose interest.

I won't smoke anything so dry it crunches. I would rather wait and humidify it again. Though you can just wet a rolled joint, in a rush.

I like the smell of flowers as they first develop. Mid flower, through to cropping. These are wet smells. Partially because it's sensation and sinus condition. The smell of fresh cut grass is gone when it's dry. The morning air when camping, is all about the RH in the area. Burning the lawn trimmings later, won't give that smell again.

There is no joint that tastes the same to the bottom. It's not the same joint as when you lit it. Not here anyway. Perhaps if everything about your environment is always dry, then it gets no drier. Explaining why you see no change. I'm one that will wet things again.

You can play around with the effects of RH on taste, by smoking in the moisture stream of a humidifier. Even after the driest of weed is burnt, you can inhale moisture along with it, and it tastes fresh. Dry mouth is not helpful, when trying to wash things out of the smoke. The difference is everything.

I should design a proper vape, that puts the RH in place.

The other wild thing im learning through wine is fault detection based on palate PH. We average between a 6-8ph in our mouth roughly 6.2-7.6 (averaging 6.7 technically). When you taste a wine with a more basic palate its easier to detect certain faults. Flavors are more prominent. When you have an acidified palate, they become nearly unnoticeable, imagine after eating a salad with a vinaigrette. Or after smoking weed or a cigarette, which lowers ph. Id love to play with this idea. Terpene presence on a more basic vs acidic palate. I bet it makes a huge difference.

 

[Douglas.Curtis]

All I do is take small hits to taste it. Two or 3 licks, and I'm emptying out bowls, that others want to finish. It's almost like I'm vaping, with the bottom of the bowl often still green. Once it's releasing carbonised dust, I loose interest.

The last hit in the bowl should taste nearly as good as the first. Hell, the damn *exhale* of the last hit should be tasty enough you want to chomp it like a burger. The ash should stay in place and be super fluffy from a tightly packed bowl. At least that's the way I like it.

Flavor going downhill fast after each hit is an over nutrition issue. Have to keep in mind the very definition of a hyper accumulator plant (like cannabis) is how it visibly hides the fact it's packing on excess elements and ruining end quality of the flower. When you *see* the plant is overfed it's already too late in most cases. Shoot for the zone just above too little, where the plant begins to grow quickly and healthily. Above that is ruining quality.

 

[Ca++]

My bowl starts damp, and ends half way through as it's dry. I don't like the last bit, as it's been vaped. All the nice smells that come off while it grows, need only the heat of growing, and the moisture leaving during grow, to vacate the buds. So add a little fire an they are vaping off. All the evaporative power seen in flower, amplified. It seems illogical that the last would taste like the first. I often wait for people to pipe in with their own opinions when you say this, but feel they might not want to say something that makes their gear look second place. If yours does as you say, I will take second place. It's not feed related though, as every bit of weed I ever had, is exactly the same. Some of which I did outdoors, in some pretty poor conditions.
I just keep looking for why you might think this. From pallet to location. I don't know what, but think it's you. The description 'dank' says damp and gooey to me. Which isn't your starting point, from what you say about your dry lifestyle.

 

[Douglas.Curtis]

My bowl starts damp, and ends half way through as it's dry. I don't like the last bit, as it's been vaped.

Right... because the terps you have are not as complex as mine. The most fragile monoterps begin vaping off at around 70F... so anyone growing hot/wet is going to have significantly less complex terpenes due to fewer starting materials for polymerization. I assure you, the exhale of the last hit in my bowls is very tasty and has amazingly little 'burnt plant' flavor.

The description 'dank' says damp and gooey to me. Which isn't your starting point, from what you say about your dry lifestyle.

My flowers are 'dank' due to the resin and quality, only the desert around me is dry. I cure at 55RH in jars, just like every other accomplished grower.

 

[Ca++]

I apolagise for the stupidly long post, and invite angry faces if you would rather be on twitter, so ain't reading it

I'm just mulling over a gap in my knowledge here. I don't really know how they say, for example, a terp has a vapour temperature of 70f.
I'm going to talk water, as it's a more familiar topic. We are presented with the vapour temperature of 100c. We know from school that going up a hill lowers this temperature, as there is less atmospheric pressure, lowering the vapour point. They don't talk much of RH, or deficit. You can see where I'm going here. Water has this vapour temperature of 100c, but actually we loose water not because we reach 100, but more related to VPD.
Switching this to your grow, you have the low temps, but in terms of VPD, you say they drink a lot.
I have to weigh this up, and consider if your environment is one that preserves things better, or looses them. The temperature suggests, as you say, that you should be keeping these things that are easier to loose than water. While your VPD and it's effects we can see on the water, suggest you actually loose more.

Perhaps without actual measurement, the notion you are keeping more of these light components, to build heavier ones with, isn't to be taken for granted.


Almost as a different topic, we have the fact these terps are generally carried in water. Another chem we like, is THC. It vapes at about 190c. Ethanol vapes off at 80c. Yet, looking at extraction, as the ethanol vapes off at 80c, it carries the THC away with it.
In this sense, the water leaving, is a constant stream of terps leaving. Many of us know how peaks in RH will carry smells through filters, as the smells are in the water vapour, which carbon doesn't catch.

What I'm looking at here, is the importance of two roles in terp loss. One the terps vapour point, and the other VPD. Most evidence suggests VPD is driving losses more than vapour point temperatures taken as fixed values.


All of this sounds like I'm trying to erode your terps content, with reasons for losses. So, where does that leave me, with my warmer room. How do I not loose these terps, the moment they are created. Which was a suggestion you made.
I can't be sure, as I'm just following the yellow brick road as I post. If I went down that rabbit hole though, my kettle wouldn't boil at 100c. The air got thicker. Looking at my bud, is the terp trying to evaporate into the air, or is it actually in a different substrate. Back to where the story started.. I don't know where this 70f number comes from. I could guess though. Which has real significance to how we apply that knowledge.

For me, the importance of VPD seems to out weigh the vapour point issue. It's almost like vapour point was the origin of the story, but with VPD, we have found the wizard.

 

[Douglas.Curtis]

Switching this to your grow, you have the low temps, but in terms of VPD, you say they drink a lot.

They drink a lot because the RH is also low. Low RH drives transpiration up the same way warm temperatures do, which is why hot and dry overtaxes the ability of the plant to transpire healthily.

Perhaps without actual measurement, the notion you are keeping more of these light components, to build heavier ones with, isn't to be taken for granted.

After reading maaaaaany studies on terpenes, and the effects enzymes, pH, temperature and hydration levels have on them, I'd say it's been measured and done to death. There's a massively complex process going on well before harvest you seem to be unaware of.

What I'm looking at here, is the importance of two roles in terp loss. One the terps vapour point, and the other VPD. Most evidence suggests VPD is driving losses more than vapour point temperatures taken as fixed values.

This I cannot help you with at them moment, I only have personal experience to draw on.

(p.s. To anyone reading this... loose is what happens to hinges of a door, and the neighbor's daughter, when they're banged too hard and too often. Lose is what most people do in poker. Common typo being spread by people who didn't know. Now you know. )

All of this sounds like I'm trying to erode your terps content, with reasons for losses. So, where does that leave me, with my warmer room. How do I not loose these terps, the moment they are created.

How do you not lose these terps in a warm room?
You don't, and that's why your grow room smells so nice. They're going to evaporate and be lost. While you do not lose 'all' of your monoterpenes, you can bet the most fragile ones will not be polymerized in your end terpene profile. These little monoterps are what make very complex terpenes possible.

For me, the importance of VPD seems to out weigh the vapour point issue. It's almost like vapour point was the origin of the story, but with VPD, we have found the wizard.

I have seen almost nothing but confusion and problems since VPD was discovered in the cannabis community...

 

[Ca++]

Well it's VPD that defines losses, not vapour temperatures. Temperature is just one part of the VPD calculation. You have spoke of 70f because you read it somewhere, but in reality you use RH as it's the more relevant part of the VPD story.

I don't use VPD myself. A computer could, and in return modify the tank for the prevailing conditions. I'm a bit more seasonal than that though. Month by month you might see some modification, but generally my environmental controls are static for weeks on end. My room at the mercy of the weather. There is only so much we can do, and VPD is far from an exact science to worship. It's more like an explanation with guidance notes. As an example, two growers could have the same VPD in the canopy, but not the same air circulation. So one grower is actually using quite a bit more water, and should use a lower EC. The charts can't tell them this though. They are just tools, but more tools is always good, if we can use them.

The terps info available is also a huge library of data, that I don't feel I need. Things like the vapour point of lab extractions, offer me no tangible benefit at the growing stage. I did enjoy reading about the main contenders, in terms of our pallet. I guess that first sweet smell at 4 weeks I like, could be easily pinpointed if I looked. The question is, would I do anything about it.

There is a saturated weed market, driving down prices. There is money to do lots of trials. Big growers are all looking for a product that sets them apart. You have been freely sharing your idea for years now. This might not be apparent, but people doing horticultural courses often need to prove themselves. To get a grade, they must identify an idea. Construct an experiment. Analise the results. Draw conclusions, then do a presentation. These forums offer a range of questions worth looking at. It's perfect for the academic who has a great memory, but lacks original thought. Or the many people just looking for the next new thing, because they are businessmen. They come for genetic material quite often, but a very different opinion on how to make a product that sounds like no other, won't be ignored.

It's nice to come here and see the diversity we have between growers. It's really not been the same since legalisation in the states has produced song sheets we can all sing from. We have been corralled from some of our fringe views, by solid evidence. However, sometimes some crazy ideas add the diversity we need, to find things in places we would never of looked. There are seedbanks in Denmark, that cater to their outdoor market. Outdoor, in Denmark? I won't be running your numbers, as I don't have the environment. Do you have a diary though?

 

[Douglas.Curtis]

Well it's VPD that defines losses, not vapour temperatures. Temperature is just one part of the VPD calculation. You have spoke of 70f because you read it somewhere, but in reality you use RH as it's the more relevant part of the VPD story.

The only bits I really want is the bottom end RH where plants are about to begin stressing due to an overtaxed transpiration rate, and the point where the plant begins growing side stems inside the flowers. The 70F is info from a study done on terpenes and their vaporization points, and when combined with 69F being the optimal cannabis temp for growth (in a few studies), I have found amazing terpene polymerization at 69-70F and have not looked further.

What most growers are not aware of is the constant polymerization of terpenes as the plant flowers. That means 60 days of monoterpenes chaining up into di/tri/quad/quint terps along the way. So question... what makes a heavier molecule? Adding a monoterp to a tri-terp or adding a di-terp to a tri-terp?

When you can smell your monoterpenes in the room, they're not chaining up to di-terpenes nearly as quickly as they would at a lower temp with more of them available to do so. Without fail, the terpene profiles in cool/dry cannabis are more complex than hot/wet grown.

I don't use VPD myself.

Yeah, neither do I. LOL