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Seth Baumgartner and Jason Van Leuven open the mics for your crop steering and cultivation questions.
Kaisha [00:00:05]:
All right, what's up, gromies? Welcome to AROYA office hours, your source for free cannabis cultivation education. I'm your moderator, Kaisha, and this is episode 106. Shout out to our live viewers on hangout, on YouTube and Instagram, to everyone tapping in on Spotify, Apple Music, YouTube, or wherever you listen to your podcast. Thank you for your support. And if you like the pie, drop us a review. We absolutely appreciate your feedback. Seth, holding it down solo today. How you doing, my friend?
Seth [00:00:32]:
Not too bad, Kaisha, how about you today?
Kaisha [00:00:34]:
I'm doing good. Good to see you. We've got some great questions in the bank and I know some live ones will probably be rolling up, so I'm just going to, let's just get into it, shall we? This seemed like a really good one to start with, especially lately we've been talking a lot about PH. Spencer dropped this question. They wanted to know, can you go over the relationship between runoff EC and poor water Ec and how that relates to runoff ph and the ph of your substrate?
Seth [00:01:02]:
Yeah. So if we're looking at pore water EC versus runoff EC, there's a few things to take into consideration. So number one, are we slowly reaching field capacity without pushing any channeling before we reach that? Because if you're irrigating too much, a lot of times you're pushing water through too fast. Once the block hits a certain saturation point, water will tend to conduct down through the media without homogenizing with the nutrient solution within. So when we're looking at that, like, let's say my goal is to go get a runoff sample today and I just push, you know, a twelve minute feed to accomplish that. My runoff sample's probably gonna actually come back for PH and Ec very close, maybe slightly elevated from what my feed EC and pH would be. Um, if we're looking at slowly bringing that up to field capacity over one to 2 hours and actually getting runoff at the end of that conf, that field capacity, when it's homogenized, our runoff EC will be slightly different than the, uh, pore water EC. A little lower, a little higher sometimes.
Seth [00:02:01]:
And that's a good reflection. But in terms of pH, what we're looking at is that ratio between positive and negative ions. So when we're looking at a plant that's, you know, feeding well, we should see in that runoff, uh, EC and pH, you know, a slight drift sometimes a little bit down on the EC versus poor water, and then oftentimes a little, uh, you know, 0.1 to 0.3 ph difference. If I went in at 5.9. I would expect a healthy plant to be feeding and giving me a runoff ph of 5.5 to 5.7. And that's just because, you know, we're looking at that positive and negative balance and we're only pulling the negative out of it which is making the solution more positive. And in this case, you know, some of the ions we're looking at aren't just hydrogen ions, they're other positively charged ions in solutions. So as we adjust that, that ph is going to start to fall.
Seth [00:02:52]:
And that's part of why we usually discuss looking at five to 15% runoff. That's generally an amount to replace that nutrient balance and maintain ph. And ph is a big indicator of what the balance of nutrients is or actually is inside of the root zone because, you know, we don't have a sensor that we stick in there to look at, you know, how much actual plant available elements or plant essential elements it's pulling out. So at the end of the day, you know, the relationship that we're looking for is looking and seeing, okay, are we getting adequate ec in our runoff? You know, if I don't have a root zone sensor I want to make sure that hey, I'm hitting three to 4.0 in my runoff, 1500 to 2000 ppm. Going higher all the way up to 4000 is not uncommon. And then in pH really just don't want to see that to start to drift if it's going, you know, if I'm reliably putting in at 5.9, coming out at 5.6, that's great. What you'll tend to find is if you don't push runoff for like let's say a week at a time. When you do push runoff now, a lot of times you're going to see your ph come back and your runoff ph come back at like 5.25.0.
Seth [00:03:57]:
And once we've drifted down to that point, really restricted nutrient availability to the plant on all levels, especially our NPK. So as far as that relationship goes, one of the best things you can do is make sure that you're actually achieving field capacity before you get runoff. And a great way to do this is to go look at your p one series and say, hey, I've calculated that over these five shots I'm going to add 600. My goal is to not get any runoff until I've actually added that 600 ML or very close to it. You know, if my last shot is 80 ML, that's where I want to see the runoff. If I go in and watch that p one cycle and I'm starting to see runoff. You know, after the second irrigation, that's when I'll pull back on that irrigation duration and potentially space the uh, the irrigation shots out just a little bit. Maybe take it from 15 to 20 minutes in the spacing to give that volume of water a little more time to wick around the media and homogenize.
Seth [00:04:54]:
And uh, like I said, if you're, if you're seeing that runoff or we'll call it actually channeling during that p one cycle, that's just a sign to slow down your irrigations and make sure that you're actually getting good water use efficiency on these plants so that we know like hey, we're not pushing water straight through and not giving it a chance to make any effect on the root zone.
Kaisha [00:05:15]:
Appreciate that overview. Seth Spencer, we appreciate your question. Thank you for asking it. Okay, so you kind of answered this question, but let's bring it home. We got this from Nick. Nick wrote, when crop steering a medium in generative phase, should we be aiming for runoff every day or is it okay if we get close to field capacity but not quite hit runoff?
Seth [00:05:36]:
So I mean this is where the situation comes in. That's, do you have time series data monitoring in your root zone or not? Because if we can look at the EC in the actual root zone, we can make better decisions about whether or not we want to push runoff that day or not. My general rule of thumb is I don't like to go more than three days without runoff because typically on that third day I'll start to see a ph drift downward. If I push it out to a week, that might be when we're hitting that 5.2 or so runoff. And at that point we're probably going to see some plant health symptoms. Not, not 100% of the time, but there's a good chance that that's what we're going to see. So you need runoff basically that's the, that's the whole drained away system like we're replacing. You know, an important thing to remember here is whenever we're using salts, we're operating in a hydroponic system.
Seth [00:06:24]:
We have very, very good control over our inputs and using those inputs to manipulate what the outputs in terms of runoff should be. And in that situation, we always want to be replacing that nutrient balance. And ph is our indicator that we're actually back in balance because that's the easiest thing we can measure rather, you know, I mean the other option is to take a runoff sample and go into a lab and try to analyze what's in it. Most of us don't have a lab that's capable of doing that. And it's, and it's cost prohibitive compared to just using pH as your indicator for nutrient balance.
Kaisha [00:07:03]:
Awesome. All right. And then, so thank you Nick, for your question. So I'm moving on to this next question. I love it when the questions are all kind of related. This one came from Terp Fiends PDX. So they wrote I can't get my EC to drop below 5.5 to 6.6 after my p one input around four. Getting plenty of runoff.
Kaisha [00:07:24]:
Am I channeling? How do I correct if I do need correction?
Seth [00:07:28]:
You know, if you can't get your Ec down, one thing obviously is to lower your feet Ec a little bit and push some runoff. And then like I said, just watch that p one series. You know, you should be able to time your irrigations and your irrigation volumes to a point where you know when you're going to get runoff. If we are getting channeling, if I have a five irrigation series for my p one or let's say an eight and I get, you know, runoff at four, that means I'm channeling because I'm seeing that runoff happen before I've actually hit field capacity in terms of volumetric water content. So if my media were to hydrate up to a 65% like a lot of the finer ground cocos out there or rockwool, and I see runoff coming out after that fourth irrigation and they've only hit, let's say 52%, then I know, okay, that's too big of an irrigation too fast. I need to slow it down, space it out and figure out what this media can take. You know, in a, in a perfect world, if we wanted to go as generative as possible, we'd have, you know, a big pot and one big irrigation every morning and that's it. But the reason we go with a p one series is because we're working with pots that are small enough that we want to be able to actually achieve a decent dryback in the daytime and bulk those plants during midflower.
Seth [00:08:41]:
If we had too big of a pot, we don't get enough dryback during the daytime to actually bulk those without just keeping them highly and possibly oversaturated. So that's where some of this irrigation calculation comes in. If I've got a one gallon pot, I can't put nearly as big of an irrigation on that without channeling as I could. Let's say a three or a five gallon pot. However, because I'm getting that daytime dry back, getting enough air into the root zone, I'm able to hit those successive p two irrigations and steer the plant towards more of a bulking behavior. So that's, that's really the big thing to keep in mind when we're looking at these generative irrigations is like the extreme would be you know, one really big irrigation, feed it everything at once and then you know, give it the longest time between pushing oxygen to the root zone and forcing respiration more and more. And we don't do that, we're not going to see that bulking behavior. That's why historically if you've grown a five or seven or ten gallon pot you were able to produce some very quality flour, especially if you have good genetics.
Seth [00:09:41]:
But the yield would leave something to be desired. It wasn't something that was quite as important until we've seen commercial growing and commoditization of prices. That's where we've got to look and go and that's where we're seeing too. Some of these older genetics that are a little more finicky and want to be steered super generatively their whole life cycle are tough to grow in a commercial situation because were trying to balance like hey weve got a genetic that weve you know, selected over several generations the last 20 years to produce a specific nose and a specific cannabinoid profile but usually werent selecting for yield or ease of growth. And so now when we see like hey if you've got a plant that is difficult and you blow it up to let's say 2000 5000 sqft in one room, now it's a lot tougher to manage that plant and that's where we're seeing, you know, kind of a little bit of a traditional ag approach is in terms of genetics coming in and saying hey you know you've got a facility or I grow a farm that is most profitable when its producing a certain type of genetic because that genetic grows to the best of its potential inside of those parameters. And then once you start planning a business around that youve really got to evaluate like hey if Im going to grow a strain I know that I need you know, based on pricing x amount of grams per square foot, can that strain deliver it and can it deliver it in the same growing environment as other strains? So using lemon cherry gelato for example, the best yields and some of the best, you know, cannabinoid testing I've seen come from people deciding to mono crop that strain because the market potential is there, you know, depending on what, what state you're in, you and what, you know, brokers and dispensaries you're working with, you might get a pretty hefty premium for the lemon Cherry gelato. But when you try to grow it with some other strains under the same program, you might see, you know, 1.8 to 2.5 pounds per light as a metric. Whereas if we can mono crop that strain and not have to have it in the exact same conditions and same timeline as some other strains, we can start to see that 3.4 to 3.8 pounds of light.
Seth [00:11:53]:
So a lot of it just comes down to business planning and really, you know, evaluating your return on investment. So if I put, you know, two out of the eight benches in one room into lemon cherry gelato, but I decided to do it under all the same conditions as I did with Oreos next to it, which is a quicker flowering strain, much easier to grow, I would expect that Im not going to get the best performance out of that lemon cherry gelato. And thats really one thing thats tough for growers, because as impassioned individuals, one thing that I always love about the cannabis industry is most of the growers I work with are very passionate about the actual plants theyre growing. Whereas when we blow it up to very big scale, ag, you much more looking at, like, how much money you can pull out of that area of land. Right. And because it's, you know, kind of completely opposite and more passion driven. You know, we, as growers, tend to try to want to grow the things we want to grow, and then we've also got to deal with the market. Unfortunately, the market's driven by a lot of different factors, whether it's music, social media, you know, name all the different media channels, you can find out about new strains and what's going on.
Seth [00:13:04]:
Uh, that's, that's another aspect that's tough to growers, because sometimes what the consumers want is not what's the best to grow for us. And so it's a, it's, it's a fine line, and there's a lot of balance work to do, and it's, it just takes a lot of planning and unfortunately, a lot of Roi math to figure out if it's actually worth it to grow that strain. And unfortunately, every once in a while, you're going to get burned, too. You know, like, it's, it's going to happen that if you're cranking through, you know, 80 strains in five years, putting them out in the market, there's probably going to be a few that you get that you're late to the game on, and that's just a reality. And that's, that's a constant thing that I think is, you know, number one, tough for growers, and then number two, fortunately, as we're getting farther into the cannabis market, breeders are able to adapt to that and say, okay, you know, there was a period in time where I needed to put out something new, like every three months, and now we're understanding, like, hey, if you can work with some of these lines a little longer, take them out farther in the filial generations, you're going to get better results. It's just adjusting your breeding business strategy to not be putting out strains on every couple month basis. You might have a year or two where you really slow down on those releases because you're working on a lot of stuff, but then once you get past that gap, you have enough projects going that now you're back in line to be releasing things on a really regular basis. But from a business perspective, that's tough, right? If you're going to say, hey, we're going to go two years without, you know, instead of releasing five or ten strains a year, we're going to release like one or two, and then in three or four years, we'll be back to our normal cadence.
Seth [00:14:39]:
That's certainly a pretty big business challenge if you were to ask me about it, and I don't have a clear cut answer for that because it's so dependent on what your cost of produce is, what state you're in. If you can get a research license, if you've got to take all of your. If you've got to take away from production space to do any experimentation, that's also a very hard thing to plan into your business because, hey, most of us want to know, you know, when we put clones in the room, how much money are we going to pull out of it?
Kaisha [00:15:10]:
And yeah, yeah, this industry is dealing with a lot of considerations that other agricultural industries are not dealing with. Also, cannabis industry, the regulated industry, is new. So we're really still learning. This is just the beginning, y'all. So awesome. Seth, thank you so much for that great overview. The live questions are coming in, so let's get to the first one from Instagram. Our friend Trichome Valley dropped this one.
Kaisha [00:15:37]:
They wrote, I just purchased a terras twelve sensor and I'm seeing my poor water EC at 5.5 ec but my runoff says 9.4 ec. With a ph of 6.2, the plant looks quite good. No real burning. What number do I go with? Also, I'm just thinking, too, that prior to irrigation, I was at 35% volumetric water content and around 9.2 pore water EC. Is the runoff more a reflection of what pore water EC was in the pot prior to irrigation? Thank you. Times a million. Did you get all that, Seth?
Seth [00:16:12]:
Yeah, for sure. Um, typically, what I go for is looking at the root zone EC, because my leachate is going to be a diluted version of what's in my, my pot. You know, if I've been stacking my EC successfully like this, this customer has, um, I'm going to see, you know, an elevated EC coming out of the bottom of the pot. That being said, that's also going to be diluted by what I put in. So if you're putting it in too fast and we're actually seeing, like, let's say, some channeling, then it's not really a reliable number. I always like to look at what's going on in the root zone for EC in that time series so I can say, hey, what is. What is my ec at the wettest point, and what are we seeing at that extreme dryback? And, you know, for most sensors out there, what we'll see is at the end of a dryback, especially when we stacked, you know, and it depends on how much you've stacked up, where you start to see that exponential spike on the graph and actually draw that real quick. If we had, you know, let's say, snap.
Kaisha [00:17:09]:
Front row ag, whiteboard is coming out, y'all. It's my favorite.
Seth [00:17:13]:
You know, let's say this is our water line coming in. You know, beginning of the day, like, here's our day mark. A couple hours in, we irrigate, and what we should see is our EC line looking a little more like this. We're gonna hit a high point right before we irrigate, and then as we irrigate, we're going to see that come back down and intersect like that. Sorry, I wish I had more colors. We'll do that next time. And, you know, what we should see is at the end of this dryback, and it depends a little bit on what sensing technology you're using. We'll see that EC start to rise.
Seth [00:17:52]:
And part of that's because water is leaving the block. Because water's leaving the block because the transplant's transpiring and we have transpiration, but it's not if we're stacked up properly, not pulling salt out at a rate that's linear compared to our dry back. So at a certain point in the dryback, we actually see the salt ratio compared to water in the pot starts to go up exponentially. And, you know, part of that is an artifact of sensing technology. But when we see that you're usually low enough in a dry range, in a dry back range that we might be approaching temporary wilting point, which once we hit that, you know, which, you know, in rockwool is much lower in coco, usually somewhere between twelve and 18%. But once we've hit temporary wilting point, we've interrupted that plant's respiration and transpiration process and actually slowed it down. So we've affected a sizable percentage of that plant's life cycle and taken it out of producing plant matter and cannabinoids and forced it to go into, you know, reactionary state, basically drought response, which the plant's response there, even though it's starting to wilt, it's going to close up its stomata, it's not going to bring up as much water and it's going to do everything it can to just survive that, you know, pressure difference. So in terms of root zone Ec, what I look for in determining when to call my dryback is when my EC line, you know, and with some of the newer sensors, it doesn't spike as high, but usually as we get lower and lower, we'll see it go, you know, almost exponential.
Seth [00:19:20]:
And that's where to start, calling the end of your dryback in your specific media and stacking situation, you can always push it harder. But if we start to see readings that are really, really high, we know that, hey, we're probably going into a zone of salinity where we're actually going to cause some plant stress. And that's not what we want. We want to guide the plant, not stress it to the point that we see some sort of negative effect on production.
Kaisha [00:19:47]:
Outstanding. Thank you for that, Trichome Valley. Thank you for your question. Good luck and enjoy that terrace. Twelve. Okay, we got this question from apex gardens on Instagram. They're wondering, can you talk about the correlation between bulk EC and poor EC? I know that you can determine poor EC from bulk EC via the Hill Horst model.
Seth [00:20:09]:
Correct. You can. So bulk Ec we're looking at, you know, what is the total saturation there and then? Not total saturation. But if I were to be able to pull a sample out of that media and look at the EC there, that's what we're talking about. Poor water, you see, is what's actually going on in the pores. And that's a really dynamic number over time, because when we've got that nutrient solution in the pores, it's changing constantly, every minute, you know, not massively up and down, but we're either trending upwards or downwards in EC, depending on how the plants feeding and drying back. So poor water EC is ultimately what we want to be looking at because that's the best representation of what the plant's experiencing. And that is why, like with the t twelve, we use the Hill horst model to convert bulk EC into poor water EC.
Seth [00:20:52]:
Because if you think about how the sensor is inserted into the pot, it's just sensing that water, which technically is a bulk EC measurement. So once we convert that, we've got a much more usable value and bulk EC is a lot more comparable to leachate EC. It's just not quite as accurate compared to what's going on in the substrate. So poor water EC is really, at the end of the day, what we're looking for. And that's why AROYA chose to go with that representation using the Hillary's model, rather than just give you bulky c.
Kaisha [00:21:23]:
All right, so then, Seth, can we bring it back to. We've had a question about the terrace twelve sensor. We have the new terrace one. Can we bring it? Let's bring it back to talking about our sensor technology. How does it work in relation to poor watery sea? And why is it so much more accurate than what else is out there?
Seth [00:21:40]:
So when we look at how we sense some of this stuff, we're using dielectric permittivity. And basically part of what makes these sensors great is they are a probe that's designed to be inserted into a media that is wet. So we're not looking at something that's looking at measuring straight liquid water and we're not looking at something that's measuring dry media. It's actually optimized for the ranges that we operate in as growers. And excuse me, the main difference between the two sensors that we see is how they read EC. So at the t twelve EC and volumetric water content are two very related values that are calculated based on an electrical reading coming in. With the t one, we're able to separate those two measurements. When we look at this exponential curve here with the t one, we don't necessarily see that go exponential.
Seth [00:22:36]:
It's much more capable of sensing that EC at a lower moisture content. That being said, when we're talking about the difference between the two, if we see this exponential increase happen as we're approaching temporary wilting point, that's already a good indicator. And then with the t one, if we had a curve that was less exponential and a little more like what we see on the t one, maybe even a little flatter. What we're looking at is instead of always using that spike as our, you know, indicator that we're approaching temporary wilting point, which, you know, isn't always the case, it's just something to go look at, like, hey, it started to spike. Go check your plants. Now, instead of using this spike, we're going to look at this water line and say, hey, that's approaching 15%, that's hitting wilting point. I'm not getting the indicator necessarily from a really high speed EC perspective because the sensor is better at differentiating between the two and not spiking EC at a low range. But because of where I'm at here on my water content line, I might want to start applying some more irrigation and getting that water content up.
Seth [00:23:47]:
So it is important to look at what sensors you're using and figure out how to use them in operation. Because whether it's a what, you know, soil moisture potentiometer, t twelve, t one pulse blue lab, and we can name all the different sensors out there. All of them are a completely relative reading. You know, the only way you're going to get true volumetric water content is to measure a dry pot. Hydrate it, measure it again on a scale, figure out your grams of water. A gram equals a milliliter. Now you can look at what the volume of water that that pot actually holds. Now, in practicality, it is incredibly expensive.
Seth [00:24:26]:
And then also you have to develop a progressive model if you want to use like, load cells out on your benches. Like, yeah, it'd be great to put a bunch of plants on scales, but then we have to develop a model that says, hey, we have to isolate the increase in mass every day on that plant from the actual water content that we're putting on. So long term, it becomes a lot more difficult to really keep track of, like how much water am I putting on every day versus how much biomass am I building? And that's where the root zone measurements come in, because that stays consistent. We're looking at the same measurement all the time and we're not basing it on trying to see the difference in accumulating weights, I guess, is the best way I would say it. So old school technology, they did used to use load cells quite a lot in greenhouses, but again, they're very expensive, they require service, and it's a lot more sensitive to operator error, I would say, because you have that accumulating weight, and different strains are going to pack on at different times, different amount of weight every single day. So when we take it back to VWC, as long as we have an accurate reading, we can figure out that, hey, 1% VWC in a one gallon pot equals 37.85 ML. If I see a 20% drop in VWC, 20 times 37.85, I know exactly how much water to put on. Whereas if I was looking at just grams, I would have to figure out roughly how many grams of water I lost in that day and then compensate with how many grams of plant matter did I grow during that day, which at different points of the life cycle could be reasonably significant.
Seth [00:26:07]:
If you're really good at growing weed.
Kaisha [00:26:11]:
You rocks. Dropping some science, but also gromies, you're coming through with some great questions. We really appreciate it. All right, we're going to keep it moving to the next live question we got here over on YouTube. This came from Lloyd. They asked, when running generative in a two gallon or one gallon, when is the last p two event, roughly, are you running more than 18 hours of a dry back?
Seth [00:26:37]:
Yes, more than 18 hours. In fact, in a classic generative state, the way I'd call that, whether I want to use a two gallon or a one gallon in my situation is during generative, whether I actually have to add a p two. So, in a classic generative model, and not just classic, but what we define as the most generative, were using only p one s to achieve field capacity, you know, within one to two hour, a one to two hour window, usually one to 2 hours, ideally two after the lights are off. And that's just to get us, you know, the best transpiration before we start putting that water on there, we get the most rigidity. That's when you see your plants, the leaves come up, and they start, you know, as we say, praying really hard. That means they're very much ready to take on that water and start putting it to work and building plant mass. So my advice would be, start paying attention if you. If you have time series data monitoring, and you can see what that VWC is doing in a very.
Seth [00:27:31]:
In a well steered and, uh, proportional. And by that, I mean, you know, great plant to pot, plant size to pot ratio in that first three to four weeks, we shouldn't have to put on any p two s if we don't want to. And then the next gap or the next hurdle is, hey, we go into bulking and that's where you know the difference in a two gallon and a one gallon, you're going to be able to put more shots on a one gallon and bulk it harder. Uh, but then at the end of that, ill go look and say, hey, my last two weeks or so for my ripening period, did I have to add a p two there? And thats really were looking. If you had to have a p two in your generative phase in the beginning, you know, early flower, that means your plants getting too big for its pot to be steered the way you might want to. And although some strains will be fine, you might find that others, if the plant outgrows the pot too quickly and you dont have a, a chance to pull back generative at the end and ripening, you might not get the quality you want to see out of that flower. So in this case, like I said, just try to eliminate those p two s. And if you're in the one gallon and you can't because the pots drying down and you know that, hey, right before the lights go off, I can already tell, like, I look at the last few days and you know, that value is going lower and lower and lower, like it's gone from, you know, 30 to 28 to 25 to, hey, tomorrow it looks like it's going to hit 18.
Seth [00:28:46]:
Okay. Then I'm looking at putting a p two on, just a corrective shot about 2 hours before lights off. And if I could track and say, hey, I want to, 25% is the bottom range of my dryback goal. But this one's going to hit 18 2 hours before lights off. I'm going to put about a 7% corrective shot on there to make sure that I'm not potentially going into that, you know, temporary wilting point territory.
Kaisha [00:29:12]:
All right, Lloyd, there you go. A little bit of advice from Seth. Good luck. Thank you for your question. All right, we're going to move on to this next one. This one came from Boxwood farmer 120. They're looking for a small overview of hydrostatic pressure versus osmotic pressure and how it's applied. You up for it?
Seth [00:29:35]:
Yeah, a little bit. Hydrostatic is not my specialty, but osmotic I know a lot about. So we're looking at osmotic pressure. Look at the ionic concentration difference inside the root versus outside. Inside the root we've got sugar molecules. Outside we've got salt molecules both are charged ions dissolved in water in this application. When we look at the root generally, well I guess I can tackle hydrostatic a little bit. When we look at the root, we're looking at in a healthy plant, that osmotic balance between the salinity outside and the sugar it's built up inside.
Seth [00:30:05]:
So if our salinity gets too high outside and we don't have enough sugar inside the root, uh, we can't defeat that osmotic uh, pressure. We can't pull in water and nutrients very well and then vice versa. If we take and build up that EC in the root zone and then the actual EC, not the EC, but the sugar content inside the roots becomes really high and then we cut out the salinity from the root zone. Now we've got a situation where all those ions want to flow from higher to lower concentration without regulation. We see, you know, root membrane disruption, just root death because we have literally sugar exploding out of them into straight water because it's not being balanced by that salt. We talk about hydrostatic stress. That's when we're getting so low in moisture content or so high that we're not able to facilitate that exchange either. So on the other, you know, on the high end, were not looking at a whole lot of hydrostatic pressure issues.
Seth [00:30:57]:
Its just theres not enough oxygen in the root zone. Once we go down low enough to the point like lets say in coco or 15% in Rockwool, maybe down to 6%, down to two, were hitting that point where we actually do hit a water pressure issue because the media is starting to hold onto the water harder and its taking more energy to pull water out of the media. Hydrostatic issues are something we should never approach in commercial cultivation because as we approach that we lose efficiency in plant growth. So that's, and that's why we talk about like temporary wilting point versus permanent wilting point. So if I'm in coco and a lot of coco growers know this, you a great, a great amount of them use coco because we'd say it's more forgiving. And part of that is, hey if I have an emitter plug up or I screw up the irrigation scheduling and I go in there, I see a few plants wilted, I can bring them back. Whereas in Rockwool if I overdrive it's, you see them wilted, just go cut them down, you're not going to bring them back. But that doesn't mean, you know, just because the coco is more forgiving, that doesn't mean we lost efficiency and left grams on the table when that wilting point occurred.
Seth [00:32:01]:
So I think that's an important thing for growers to look at is, you know, we're trying to optimize, uh, osmotic pressure and the, you know, the stress we can apply to the plant through that never hydrostatic pressure. So, you know, with our long drybacks, we're essentially trying to induce a drought response, kind of, but not actually go into drought response mode. We're trying to tell the plant like, hey, you're not getting rain all day, so don't grow like crazy. But you're not going down to the point where you're almost wilting and going into full drought mode where you're, where the plant is closing its stomata and trying to dramatically reduce transpiration, because anytime we reduce that transpiration amount, we're reducing biomass and oil production.
Kaisha [00:32:53]:
Amazing. Thank you for your overview there, Seth, but also Boxwood farmer, thank you for that question. It's really cool to be able to make that distinction between hydrostatic pressure and osmotic pressure. All right, moving on. We got this one from golden child on YouTube. They wrote, I'm trialing out different brands of nudes. A couple of them recommend no higher than 2.5 ec input. One brand even calls to reduce input.
Kaisha [00:33:20]:
If input EC goes above 20% above input, three Ec they said to, and I think they mean not ever go above six EC for any reason. Would you recommend following company guidelines or run them like I run everything else? Six to ten ec in early flower, four to seven EC ish later on in flower.
Seth [00:33:44]:
So, yeah, I think a good place to start here is to reel it back ten years and lets look at what, you know, nutrient companies were recommending, which typically was a much lower eC feed than were going for today, and pushing, you know, more regular runoff. And part of the goal there is like, hey, youre forcibly controlling the root zone. You see in that situation and were not pushing it super high, so it's not likely you're gonna hit a point where it gets out of control. Now, once we introduce sensors to the equation, that's when we can start pushing that 3.0 to 4.0 feed and really having more root zone control. And if you want to think about how a, well, let's just say any chemical company is gonna look at applying their chemicals, whether it's a fertilizer, pesticide, or herbicide, you know, you name it. They want to have their bases covered and give you instructions that are gonna give you success despite your potential lack of tools because when that fertilizer company makes that recommendation they cant assume anything about how you grow, your experience, what level of tools you have to actually gain insight on whats going on in your root zone. So theyre always going to steer you towards a little bit more conservative input value and probably a little bit more liberal runoff value so that youre not letting your ph drift too much. And the idea is they want to give you a recommendation that, you know, you're at most, they're asking you to take some runoff measurements and otherwise they want to give you the simplest formula for success.
Seth [00:35:13]:
And unfortunately, you know when you define success as producing a crop versus producing the optimal crop, that's where some of these recommendations kind of fall short. So in that situation I would run that fertilizer the same way you run every other. And look at your, if you have root zone EC values, keep those the same because when we talk about going into these higher PPFD and CO2 levels, uh, we need that amount of EC. You know, run after run has shown that hey if I've got eleven 1200 ppfd in that room, I need a six to nine baseline EC in the root zone to provide adequate nutrition to those plants because they're essentially an overdrive compared to, let's say I used to run at six to 800 ppfd, you know, now I've got all these inputs and that plant just needs, if I, if I had a table that is plant production, you know, my legs are air, you know, how, how dry can I get the room to facilitate transpiration? Obviously there's a range we want to be in, how much light can I put in, how much CO2 and then how much water and nutrients. And if any one of those legs is short the table's not going to be level and we're not going to get great production. Right. And uh, unfortunately EC is one of the scarier ones because without using root zone monitoring technology for EC, basically we just have to push runoff to maintain ph and adequate nutrition. Whereas if we can watch that EC stack up in the root zone and then modulate our runoff a little bit more intelligently, we can keep that ph in range while also stacking that nutrition up and having it available for the plant in the block.
Kaisha [00:36:56]:
Amazing. Golden child, that was a great question. Thank you for all of that. Good luck. Good to hear from you. All right, we're going to move it over to the hangout. Our gromy carpe dripm dropped this question. He wants to know what's your preferred DLI to run.
Seth [00:37:14]:
I usually, I like to approach 40. 40 is my solid point. You know, that's getting me in the 1000 plus PpFD range. And that's where we see max production. That being said, if you have any shortage in the other legs of your table, it's going to be difficult to run that Max DLI. So there, there are situations like, let's say, you know, we were talking about plant to pot ratio earlier. Let's say I did overgrow my pot and, you know, my plants 6ft tall, I'm in a one gallon pot and it's a, it's a big raging plant and at 1000 or 1100 ppfd, it looks like I'm going to over dry it and have to start putting on p two s during ripening. Like more than I want to in that particular situation, especially if we're looking at, you know, hey, if I can hit a certain number in quality, that's going to give me a significant premium on my price per pound.
Seth [00:38:07]:
We might want to turn down the lights, slow down that transpiration a little bit and try to, you know, maintain our ripening strategy so that, hey, we might lose, you know, ten to 20% of yield max by not really optimizing growth in those last two weeks. But on the flip side, we got a $300 per pound premium because we were able to produce something at 28% to 30% THC versus 24 to 25 or, or even lower. So there's sometimes the choices we have to make and, you know, the biggest way to start to figure out how that impact, you know, affects your crop is just crop registration. So looking at your irrigation strategies, looking at your yields, looking at when you made those changes and starting to draw correlations between, hey, on this train we ran three weeks of ripening and we actually saw a significant increase in THC, THCA content and TErp profile compared to running it two weeks or one week of ripening. Now, we always have to balance that. Let's say, hey, when we ran as much bulking as possible right till the end, maybe we did experience the best yields. But if I can't sell it, it wasn't really worth the time, right? Or if the price is so depressed it's not, you know, worth selling, then why, why did I do it? So I think that's, that's really where for growers and that's where it becomes tough, right when we're trying to crank through all these strains. You know, used to say, at least for me, um, I'd say hey, it's going to take me six runs to dial this strain.
Seth [00:39:32]:
I'm sure that there's a bunch of people out that are like, you know, you're an amateur, you should be able to do it easier. But really, if I'm looking at commercial scale, a two to 5000 plus square foot room, running a strain in that environment on maybe two benches, it's going to take me some time because I'm always operating in a world of averages and compromises. I can't really focus on only dialing that strain. I have to grow that basically with my standard program, see how it responds and then start to tweak from there. And that's what's tough when you only get, like I said, personally, I think before having root zone sensors, six runs was like not something I'm super proud of, but very average in growers. I talked to. Some of the people producing the best possible product are people that have been growing some of these strains for a long time and really, really dialing their environment and irrigation strategies and everything else around producing this very awesome boutique genetic. And it's just hard when you blow that up to, you know, 5610 strains in the same room.
Seth [00:40:32]:
So with some of this root zone monitoring, we're able to start to look at like, you know, what kind of trends are we seeing with different strains? What strains behave very similarly? And then also once we can see the ECPH water content, we can start to rule out some of those things. Like on the show we talk about not flushing so much. But really the reason we say that is because when you can monitor what's actually going on in your root zone without having to, it just takes that out. If I have to basically trust that my runoff sample was accurate every day, I hit the end of my p one without any channeling. Well, good luck getting it on the right plant because you have a dynamic population of plants. If you have 100 plants on there, there's a good chance that, you know, a certain amount of them depends on your uniformity. Did have channeling. So if you happen to get your runoff sample from one of those, well that's going to make it much tougher to actually run your strategy because you've got something that's not very representative of the rest of the plants.
Seth [00:41:34]:
So once we can see that, we can really make choices and say, hey, this plant's locked out. Oh, well, the EC is not high but the ph is low. So yes, effectively it is locked out, but flushing is not going to fix it for us. And that's I think, where really having time zone root zone monitor, time series root zone monitoring helps growers make choices that are actually more impactful and can also, you know, save crops. Like our goal as growers is to eventually get everything to a streamlined point where we're not being reactive, right. We know, we know the problems we're going to hit. We know what we have to do to avoid those, and we can have clean runs. But in this world where cannabis, you know, there's no crop insurance, at least not any affordable things that I've seen, we've got to try to be as proactive as possible because it's for your business.
Seth [00:42:27]:
Way better to try to, you know, start to forecast problems than it is to always be reactive because you're never going to be able to figure out what 100% of your potential, your businesses, if you're only ever to operate, able to operate at like 60, 70%. And that's something we're seeing with these irrigation strategies is that little last 10% of polishing your environment and your irrigation is oftentimes responsible for 50 or more percent of your yields. And so that's where I think the mindset growers have to get into. You know, there's that setup period in any business where it's just chaos. You're thrashing to get everything together and get through that first run. But then once you, if you have the goal of stabilization in mind and a good plan, eventually youve got to figure out what your facility can do, what 100% is, so then you can start to forecast what your yields will be and plan a business around it. If my yields are fluctuating from 1.5 to three pounds of light, and I cant tell if this next run is going to be that or not, suddenly, ive got a problem with my sales and marketing department where they dont know how much weed theyre going to have to sell next month. Therefore, they cant maintain the best relationships with the dispensaries that I want them to maintain.
Seth [00:43:35]:
And ultimately, ive been in that position before where we had some great contracts. Unfortunately, we had some things go wrong and right when things were looking great, like, hey, our reputation is good. Were our crops sold before we ever cut it down? That next round, it wont be all sold because youll lose some customers that were pretty bummed that you ended up. They didnt necessarily give you money ahead of time, but they planned on their shelf space and inventory to have, let's say, five pounds from you, and now you're giving them two. And they go, okay, well, hey, man, I measure my store inventory space in square inches. If you can't fill it up or if you can't sell, those are two reasons for me not to stock your product, and that's compared to regular ag, anything outside of the small organic sphere. A lot of farmers don't have to deal with that as much because they're working with distributors, and that does exist in the cannabis world, as well. But we all know if you want to white label and go through a broker or a distribution company, you're certainly leaving some money on the table, right, by not participating in that side of the business, and you've just got to go look at the ROI and say, hey, if I want to distribute out of my business, is the licensing, the personnel cost worth, worth what? It would be worth it compared to just white labeling it out and letting a different company deal distribution, knowing that I'm leaving money on the table.
Seth [00:44:59]:
But, hey, you know, if I'm looking at it, you know, I lose $100 per pound by going through that system compared to marketing my own. Might not be worth it depending on the size of the business you have.
Kaisha [00:45:12]:
That's real talk crop registration, y'all. We say it almost every episode. It is your friend, amazing. Seth, thank you so much for that excellent overview. All right, we got this question on Instagram. Changing gears a little bit from the real j 100. They want to know what you think about low stress training and topping. Too soon, bad or not, you know.
Seth [00:45:38]:
Low stress training is a great technique that's used historically, especially among home growers. I do it because I'm not in a hurry to produce weed at home. It's a passion project, and I'm not making money on it, nor am I, like, running out of weed anytime soon if it's just me. That being said, we talk about things like low stress training and topping. There's two things to look at. Topping. Number one, we're looking at increased that veg time, uh, because, hey, we top the plant, we've got to wait for it to grow a little more biomass before we flip to get the same number of nodes. And then low stress training.
Seth [00:46:12]:
Um, great. The best way to figure out your low stress training is to figure out a way to get your plants to grow up through your trellis. And the main reason I say that is both of those techniques involve labor. And so when we're looking at, you know, the production life cycle of a plant, every time a human has to touch that plant, it's costing us money. So even though it might take 2 seconds per plant to top, if I've got to go do 2500 of them, that's now a couple hours of someone's time that I had to pay for, and that's an additional cost to the crop. Same with low stress training. So, you know, if I'm in and where, where I see that come out in commercial ag or commercial cannabis production mostly is like in the double stack situation where it's like, hey, we've got four or 5ft from the trade of the light, and we're doing everything we can not to get the plants to grow into the light. And if I've got to go in there and tell people to tuck branches and try to do a lot of low stress training, that's where I'm really going to look at flipping a smaller plant, trying to, you know, find a plant size and structure that grows up nicely through the trellis and hits the height that I want under the conditions that I'm growing in.
Seth [00:47:17]:
Because if I have too big of a plant, that's where that low stress training comes in. And, you know, both of them are effective at boosting yields, especially in a smaller scale, more homegrown situation. But once we blow this operation up to a certain size, I mean, time is money. So if we slow down veg by a week, if we go from a three week to a two week veg, by not topping, we're saving money in the veg room for those plants. You know, they're not taking up as much square footage, light any other resources, that's only two thirds the amount of time. That's a significant cost savings there. And then really, I think the biggest thing we got to look at is like, hey, some of these techniques, you know, especially the classical ones for boosting yield and stuff at home, they really were never designed to optimize a production cycle. So we're looking at like, hey, what, what can you do with your own two hands easily to boost this crop? And also, you know, let's talk about, you know, GMO or some of the hazes that, or even the ogs that you talked to, some old school guys, they're like, yeah, I'd flower those for 1214 weeks.
Seth [00:48:19]:
Okay, find me a commercial cannabis production manager that's gonna build a business around a 14 week flower cycle. You know, the game's just changed. That's what it is. So some of these older techniques that we all love to do, even from a perspective of like, hey, I enjoy gardening, just don't have a big place in commercial plant production. You know, we want to optimize that growth cycle so there's as little human touching as possible because at the end of the day, labor is always going to be expensive, and we are dealing with a commodity now. It's not, you know, marijuana is no longer a luxury item or rare, you know, or, yeah, even rare because it's legal. Like it's just a commodity. We have a roughly known price, and you've got to hit, you know, check certain boxes to get above said price.
Seth [00:49:10]:
So you need to do everything you can do to protect that. And then once you know that price, you work it backwards and say, okay, in my business, I know what price I can get. How can I cut costs in achieving that price with an acceptable volume? And that's one of the unfortunate things about it, is I always say I love cannabis because so many of the growers I work with are passionate about what they do in the plant. And sometimes you've got to really pull back on that passion and say, hey, I love this plant. I love doing all this work, but I did some math, and I'm not going to make money doing it with this strain this particular way. And that, I think, is one of the hardest things for a lot of growers to get over is you almost skipped going from gardener to farmer to manufacturing. You almost skipped the farmer part. Unfortunately, once you get into some of these big facilities that crank over crops every week and have this high output, and you really have to balance that.
Seth [00:50:09]:
And I think that's one thing that's important for people to think about as they approach getting into commercial cultivation. Ive seen a lot of, I would say, master gardeners that produce amazing product at very acceptable yields not be able to translate that to a commercial level process. And its not because they are unskilled or unintelligent. Often theyre just driven so hard by the passion and feel so strongly that the only way to achieve those kind of results is with this meticulous, highly hands on process. And sometimes that's true that that that might be the case, but can you repeat that process at scale and still make money, is the question. And oftentimes we find if you sit down and do the math, you just can't. And then, you know, that's kind of, as a grower where you decide like, hey, do I want to hop into this commercial cannabis space? Do I want to look more at starting my own or working at a licensed micro grow, really find your niche and whats going to make you happy, because if youre very passion driven in the cannabis industry, theres different levels of money, of course, but were still working with a pretty highly profitable crop. If you have a pretty well run business, so you dont necessarily need to work in situations like I do with 2000, 5000 10,000 square foot rooms and just look around and try to figure out like, hey, maybe I'm going to go work at this place that's a 2000 square foot micro grow with three employees.
Seth [00:51:41]:
And we're all super passionate and that's how we're going to do it and we're going to live within that revenue box, we're going to make it work. And I think that's the really hard thing is if you've been growing, let's say with ten lights and you know, you had a decent yield, that was, that was very acceptable money for one person or two people coming in. Well, with the overhead that comes along with license growing suddenly, it just isn't, it's really, really hard to make that small business work, especially, you know, with the different states laws and stuff. Some states have a better program for micro growers and then you have Florida, you know, that's an example. Don't, don't move there if you're a passionate gardener.
Kaisha [00:52:25]:
Oh my gosh. Oh, yeah, let me wrap, let me just speak to that. Yes, you got to get in where you fit in, right? Yeah. I just was so surprised. Jason just logged in from Germany. Jason, can you, can you unmute and say hi, buddy? Hey.
Seth [00:52:41]:
Hey, y'all.
Kaisha [00:52:41]:
Hey, how are you?
Jason [00:52:44]:
I'm doing all right. I'm just having a pizza here in a old fashioned.
Kaisha [00:52:49]:
You having a german pizza?
Jason [00:52:51]:
Yeah, it's good.
Kaisha [00:52:53]:
Amazing. It's so good to see you. Well, you know what, your timing is excellent. We have one more question from our grown our gromy carpet drip. I'm here on the hangout. Let's go ahead and ask it and both of y'all can chime in. Carpe dripm writes. Should I be worried about hollow stems? Is this from my veg environmentals or irrigation under led? I wasn't seeing this under HPS, so I feel like I'm doing something wrong.
Kaisha [00:53:18]:
What do you guys think?
Jason [00:53:23]:
You know, holostems, like some genetics are just more proposed to having holostoms, while it's not ideal personally, don't necessarily get too worried about it. As long as plant growth looks healthy.
Seth [00:53:37]:
Yeah, absolutely. I'd fall at that. You know, we're talking about there's pith autolysis where the plants actually consuming that pith, or growing faster than its ability to create the pith in the middle of the stem. So, you know, my first approach is to go look back at veg and making sure Im giving those plants adequate nutrition for the amount of light that Im giving them. And then along with those changes just register over time just to what Jason said, you know, ive run strains that, uh, its actually a constant battle with the moms to try to get cuts without hollow stems, because that genetic is so, so, uh, predisposed to pithotolysis. Um, its genetic traits, sometimes it comes up, sometimes it doesn't, and it's another. Another one of those artifact ones where over the years, breeders have selected for nose and potency, and not the traits that are great for the growers. You know, in a traditional breeding program, we look at that and go, hey, this one sucks.
Seth [00:54:33]:
That's a bad trade. It contributes to poor rooting from the moms. It's, you know, weak branches. We all splits. It's just not a desirable characteristic. We're going to look in the other 10,000, you know, f two crosses, f three, f four that we've got in this, in this generation. Pick a better one. That's.
Seth [00:54:49]:
That's largely a result of just breeders not being able to really explore the genetic availability or variability that's present in the lines they're working with. Because, hey, if you can only pop like 50 or 100 seeds at max, that's, you know, 1% of what you want to be popping, maybe to actually get, you know, see what's out there in that cross. The. But because cannabis is dioecious and we're not self pollinating, the amount of variability is just as big as with apples. Go to the store, get an apple, pull a seed out. If you got a granny Smith, you are not growing a granny Smith out of that seed, I can guarantee. And the one you grow might actually be way better. Yeah, I mean, apples are obligate outcrossers, kind of like, cannabis is not an obligate outcrosser, but in the way we grow it, in diocese setting, we've made it outcross, unless we hermit out, right? So when we get two very different genetics, that cross, we have, you know, not 123456 females, really.
Seth [00:55:48]:
We've got, you know, in that f one cross, maybe we have four to ten phenos that are all really, really similar, but slightly the same. But then we do either selective crossing within that, or some synthetic breeding where we let it open, pollinate, and then we might see a thousand different phenos in that f two generation. And a lot of times, if we didn't. If we didn't. Weren't able to take it to that and really look at that, you know, variability and level of expression, there's probably things in there that we don't even know exist. Yeah, you might. Your winner might be there, and it might be way different than either of the parents and just totally weird and awesome. But if you couldn't pop, you know, enough seeds to find, it never makes it up.
Kaisha [00:56:31]:
Wow. Well, nature's always in charge. Amazing carpet drip. And we appreciate your question. Thank you for that. Well, before we go, Jason, you want to tell the world what you're doing in Germany?
Jason [00:56:43]:
Yeah, we're here at Mary Jane in Berlin. So if you're over here, come see us in our booth. And we're all going to be set up tomorrow, I think, 11:00 a.m. starts local time. And just looking for a great show. We get excited about meeting prospects over here in Europe, and we're going to just keep pushing AROYA, go take Jason.
Seth [00:57:07]:
Out and show him a good time. That's all I got to say.
Kaisha [00:57:10]:
Yeah, have so much fun, Jason. Take lots of pictures. And yeah, if y'all are anybody out there that's in Berlin for the Mary Jane show, AROYA will be there June 14 through the 16th. We've got a booth. Head over to booth e 88 and go say hi. That's it. Jason, have an amazing trip. And thank you for stopping by the pod today.
Kaisha [00:57:33]:
It's always good to have the whole team. We miss you already. And then, of course, Seth. Thank you for holding it down, solo producer Chris. I could not do this without you. Thank you for all for another great session. And thanks to everyone for joining us for this week's AROYA office hours. To learn more about AROYA, book a demo at AROYA IO and our team will show you the ins and outs of the ultimate cultivation.
Kaisha [00:57:55]:
Cultivation platform. If you have any crop steering or cultivation questions you want us to cover, drop them anytime in the Aurora app. Email us at salesroya IO. Send us a DM over Instagram, Facebook, LinkedIn. We want to hear from you. Don't fear not. If your question wasn't picked, resubmit it. We also have a great bank.
Kaisha [00:58:12]:
We will get to it. And if you're a fan of the pod, please leave us a review on Spotify, Apple Music, YouTube, or wherever you listen to podcasts. We appreciate your feedback. And be sure to subscribe to our YouTube channel so you never miss an episode. Thanks, y'all.
Seth [00:58:26]:
See it?
Kaisha [00:58:26]:
Episode 107. Bye.