![[AUDIO Only] Office Hours LIVE Ep 39: Crop Steering Theories, Generative vs Vegetative Steering, EC, VPD - podcast episode cover](https://assets.metacast.app/images/podcast/artwork/9vAcwW2l)
All right. It's Thursday at 4:20 PM. Eastern. That means it's time for office hours. Roy's weekly session for cultivators to hear from the experts and talk to each other about what they're seeing with their grows. My name is Kaisha, and I'll be co today with my good friend, Mandy. What's up? How you doing Mandy? Hey, Kaisha. So psyched to be here for episode 39. Uh, we're also going live over on YouTube. I'll be monitoring for your questions over there.
So don't be afraid to go ahead and send them on over, uh, be sure you're following us on Instagram and TikTok. If you haven't. You guys know how we do it. So let's go ahead and get to those crop steering questions we got this week back to you, Kaisha. Awesome. Thank you, Mandy. And yeah, if you're alive with us here and have a question type it in the chat at any time, your question gets picked. We're gonna either, have you unmute yourself or I can ask for you, Seth and Jason.
How's it going over there? Good. Kaisha, how about yourself doing good. It was nice to see you last week. Um, you ready for our first question from Instagram? We got a bunch this week. We're so excited. It's
not wasting any time.
dude, I like that. All right. So someone wrote this in first and foremost, thank you to everyone, aro for the wealth of information than the professional setting, to learn and gain a better understanding of plant physiology. My question is as the industry and home growers move toward full spectrum LEDs, could you dive deeper into the role of RuBisCO in carbon fixation and the increased grow room temperatures you would recommend. What do you guys think about that?
Sure. Uh, so let's just talk a little bit about RuBisCO. Uh, I'm no plant biologist here, but it is one of the first major. Steps, uh, it's the enzyme in creating the sugars that plants used. So it's a carbon fixer that happens inside the plant before we get to ATP. Um, as far as when we talk about LEDs, I'm, I'm not sure I'm qualified to deep dive right into the science of, uh, Resco production itself in relationship to the LEDs.
But I do like to think about, uh, what we call room temperature to, um, ratio. So it's room temperature to radiation ratio, excuse me. And so when we're looking at that, we're thinking about how much heat is produced on the leaves when the specific light spectrum hits that leaf. Right? And so with HPSS, we have quite a bit of red spectrum light, um, We've got quite a bit of infrared light and those waves are gonna create a little bit more heat on the leaves.
So when we think about changing from LEDs to, uh, or excuse me from HBS to LEDs, a lot of times we're gonna have to up that room temperature because the leave temperature is actually gonna be decreased due to less radiation hitting the surface of those leaves.
And so in order for us to, you know, achieve the same leaf P D um, and we we've talked about, uh, leaf VPD versus room VPD, uh, in this case, making a modification from HPS to LEDs, you need to readjust your, your known offset between the leaf VPD and the room P D. So when, uh, when we increase that. Room temperature. We can help the plant keep up with an actually a higher metabolic rate versus an HPS simply because we've got a higher temperature in the room.
Um, and the leaves aren't working as hard to reduce their surface temperature just with transpiration. So, uh, in C3 plants like cannabis, 97% of the water uptake in the plant is, uh, expired through transpiration. And, uh, sometimes that transpiration is what is. Just keeping the leads. Cool. And so when, uh, when we're changing from HPS to L E D, obviously we can get a little bit more efficiency.
Typically, if we do make the appropriate adjustments, sometimes we can actually grow a plant faster. Um, the irony there is that we are hitting the plant with a different spectrum, and sometimes that actually completely modifies how long it takes the plant to ripen as well. Um, and a lot of times we can get a bigger plant simply by making those changes, increasing our, uh, metabolic rate in the plant. So basically more photosynthesis can happen.
Maybe it takes a little bit longer for that plant to ripen throughout the entire cycle. But usually if the appropriate modifications are made, we can end up with a little heavier panel.
Yeah. I mean, What it all boils down to for growers is we want RuBisCOCO. Well it's action inside the plant, inside the cell to be operating at an optimal rate. If we want the most plant growth, that's why we're targeting that leaf surface temperature, you know, the 80 to 82, usually that's not just because we, you know, we've looked at it and seen, oh, Hey, plants are happiest at that rate. Or they grow the fastest.
When we start to look back into the biochemistry behind it, that's the temperature that we have the most optimum interaction and best efficiency for these enzymes to start assembling carbon and making sugars. If we slow down the temperature, less sugar production, let's plant growth. Like Jason said, you know, RuBisCO, go's building these sugars that eventually power the cells. It ends up as ATP.
Um, if we don't have the temperature to actually reinforce that production, we don't get as big of a plant. So when we're talking about, you know, running lower temps, uh, let's say during generative. During stretch.
That's been, you know, over the years of strategy, some people have employed, especially, let's say in like a, you know, double tier system to keep plant height down because we know that it's say 78 degrees versus 82, we have a lower rate of plant metabolism and a lower rate of stretch. Um, as far as RBIS goes, is concerned, uh, role in how we make our decisions goes as though I'm glad someone brought it up. That's really cool. Backend biochemistry.
Um, it's not something we think about directly. Typically when we're manipulating choices, we're manipulating the environment in the garden, but again, that's something everyone should be looking into understanding. Some of these processes is really cool because you can kind of get an insight on why, you know, why we're looking at that and then kind of extrapolate, okay, now that we look back, if I understand why we're making these choices, I can really identify some of the stuff out there.
That's bad information. You can go, Hey, that, that growth strategy you have, doesn't really jive with how I, I understand plants work, therefore, uh, you know, maybe I'm gonna modify those strategies or decide, Hey, I'm not gonna risk my crop on, uh, running 90 degrees and 80% humidity. Let's say you go, okay. Maybe it works. But from a scientific perspective, I don't get it. Not taking the risk.
Yeah. And I think last week we mentioned, uh, the balance as far as, you know, crop steering strategies go. And, you know, Seth talked about, you know, lowering temperatures for a, a generative signal. Well, sometimes if we're pushing really hard, maybe our irrigation schedule is extremely generative and we have a perfectly sized substrate. Sometimes we can keep that temperature up and mm-hmm, increase, you know, keep that metabolic rate very quickly.
So we're basically just tricking the plant physiology. So we're using maybe a really, really hard generative irrigation schedule to get that reduced node space, keep that plant from stretching, um, and, and keep those temperatures up and, and get it growing as fast as possible. So I just wanted to mention, you know, it is that balance that we're talking about.
And every once in a while, uh, and specifically we're certain strange, you can get away with some, some cool tricks that end end up, uh, giving you a major advantage.
Yeah. And I, and I think an important thing to remember when you start looking at biochemical pathways and stuff is, uh, you know, if we're looking at just sugar production, respiration, those are things that are happening inside the plant. A lot of what we do with plant morphology control is a lot more, uh, dependent on plant growth regulators in their balance inside plant tissue.
So although we're, you know, speeding up and slowing down growth, we're also, you know, manipulating different morphological traits through, uh, just plant growth regulators. A certain balance will tell that plant to stretch longer. Literally it cells are gonna stretch more versus divide for the plant to grow. So when we're looking at that, um, don't go too deep and make really big decisions based on that.
Look at, you know, there's a lot of good standard information out there and just understanding the relationship between some of these backend concepts and how we apply them is really important before you go forward with doing some more, uh, I guess radical strategies that are out there. And that's not to say that some of the stuff we do, wasn't considered radical a few years ago. Yeah.
And you know, when, when we're analyzing something like RuBisCO code, it's probably at the scientific level versus an application level in some of these operational, um, implementations that we recommend and obviously very, very cool stuff. Um, how, in the end, you can change what you're doing in your rooms, uh, to modify something like that may not be as important as what, when we look at what we're doing in these rooms to modify the end output of a plant, say that, that morphology.
So by tricking the, um, physiology to the morphology for, for an increased.
Yeah. And, uh, you know, heading down that road, if you're really gonna get that far into it, you're gonna start wishing there was like a C4 photos version of cannabis. Like, you know, you're gonna start to see some of the other, uh, other systems that are out there in different plant species that are either more efficient, less efficient. Um, you it's, it's more of a botany implant, physiology, exercise and exploration than anything. I mean,
we've, we've seen what, uh, what was done with corn in the last hundred years. So who knows what, uh, what grow in like a century from now
true? Oh, my goodness. Cannabis is century from now. Let me, let me focus. Okay. uh, we got a question here from our good friend Billbo who's on with us live. Billbo you wanna unmute yourself and ask it or shall I ask for you? No, I'm here. Hey, welcome. Hi. Is there any evidence to suggest that environmental settings should be adjusted during different steering techniques and to expand on that a little bit?
Well beyond, uh, the, the norms of what you'd see within, I guess, the HPS double-ended world and your L E D world given transpiration rates and light spectrum.
Um, you know, that's gonna kind of come down to genetics. Uh, you know, there's some genetics that can take advantage of say five, six degree increase in room temperature when we switch from something like HPS to LEDs. Um, you know, another thing to think about as well is when we've decreased the amount of water going through the plant, just for transpiration. Now we have more, uh, water in that plant that's, uh, being used for, um, for growth processes.
And so we're probably gonna have to up the EC when we get under LEDs, because the we're not transpiring quite as much.
Yeah. I mean, really a lot of what it boils down to is that leaf surface difference or leaf surface temp difference, right? Like with our I lights, we've got a lot of radiant heat coming out with the LEDs we don't. So the difference is usually with, I D we're seeing two to five degrees above room temp at the leaf surface led. We're seeing, you know, one to four degrees below room temp typically. So, and especially once you factor in your ventilation, you've got fans blowing around in there.
So really it's just accounting for that difference. And then understanding that what we're chasing is that leaf surface temp, and really trying to dial that in, you know, we're trying to keep everything stable in the room and do what the plant's telling us. It wants us to do essentially following its cues rather than, you know, focusing on, uh, what if, if my leaf surface temp says 78 and my room's running at 82, um, my room might end up running at 86 and, you know, normally for me.
I would be like, whoa, what's going on? I'd do that with customers. Actually, sometimes I'm like, Hey, it says your room's pretty hot. Oh, we have LEDs. Okay. Well then we don't have to worry about it. It's just, it's a, it's a simple math problem that needs correcting basically.
Yeah. And you know, anyone that is making that transition, I guess the easiest way to know how much you'd need to adjust is go in and take some leaf surface temperatures.
Uh, you know, I recommend taking quite a few samples, a across the, the Leafs some up in, in the higher canopies, some up in the lower canopy and compare that to the leaf surface temperatures you were seeing in, in IDs and just up your room, the, the temperature difference that you see, um, from the original leaf temp to the, the leaf temp after you've changed LEDs.
Yeah. And, uh, also if you are budgeting for LEDs budget for more deh capacity, generally, if you can't push higher than a two with your IDs, uh you're you're not gonna be able to cut it with your LEDs, given the same size room and same Dehut deh equipment. That's great. Billbo did you get your questions answered there? Yes. Awesome. Thank you for submitting. That's a good one. All right. Another one of our attendees mark is on with us. Posted a question here, mark. You wanna ask it?
You're you're he's he's busy. He's busy back there. Yeah, I'll ask it. Okay. Goi right now, um, the, the EC, so we use trim master sensors, uh, right at water content sensors. The WCS ones were crack. We got WCS twos. Now they're a little better, but they're still. Far from optimal. Uh, uh, the, what we're finding is the EC is affecting the WC, right? Uh, so we are, uh, at least the reading that we're getting from the control master controller.
So, um, when we drop the EC from like 3.0 to 2.0 week seven, let's say, uh, it, it takes, uh, the medium a couple days to balance out what it's gonna be for the next week. And we're chasing the water content because it's dropping too damn fast and we know it's not accurate. Um, so, but, but the readings that we're getting are, are, are, are not reliable. Um, and, uh, I've, I've got a, I've got a system, a DIY system in place that is water. Based on, uh, water content readings from those sensors.
So I have to be able to trust them. And I don't.
Yeah. So I, I guess this kind, let's just talk about the root of this challenge. And it comes from, uh, most of the sensors that are in these industries have come from traditional horticulture practices and we don't necessarily see the type of EC levels that we can run in cannabis for most, uh, most productive growth.
And so, you know, in something like if we're trying to grow, uh, you know, lettuce or even tomatoes who are typically never gonna see something in that say five to 10 EC range, it's just way, way beyond what the plants will happily tolerate. And so, you know, a lot of the sensors out there ha have not been calibrated appropriately or simply don't have the ability to read water content appropriately at those high ECS.
And we're fortunate enough that you know, that the terrorist 12 is, uh, A lot of generations beyond where our first, uh, EC water content sensor was, uh, you know, we've been developing these for about three, three decades at this point. Um, and so what we've done is just calibrate those up into say the 20 to semen range to, to try and hold accuracy throughout.
Um, you know, fortunately we use a patented circuitry in there that is able to support a fairly accurate, um, calibration across the board.
You know why we do see some amount of changes, you know, effective of water content on EC it's very negligible with the tariffs 12, um, that can't be said for, uh, some other sensors out there, maybe the Klima or, or the troll master, you know, especially some of the, the more cost cutting, uh, types of sensors out there, or, or some of the companies that, that don't quite have the research history that that meter group does supporting, uh, aro in this case.
Um, I don't necessarily have a great recommendation on how you can get around that other than maybe trying to, to map exactly how far off it is with your sensors. Um, and, or, or try, try to get into a little better sensor suite. Yikes.
Uh, yeah, I was just trying to see if the, if the platform handles that, uh, better. Cause I feel like it's just, it's sort of like a math equation based on what's being read. Yeah. And you know, one thing to remember too, if you've got a calibrating sensor, that's gonna be really hard. The more times you calibrate it to be accurate because what we use as a solid state calibration leaving the factory.
So when we're calculating the information coming in off that sensor, when Roy is dealing or, uh, processing that we there there's no changed variable in there. There's no trusting that, you know, the cultivator went and set, you know, max saturation at max saturation with VWC. It just is what it is. And there's no cut, you know, it's cut and dry. There's no question on it. Okay. Um, Thanks my second. My second question is on the, the open sprinkler integration.
Um, uh, I I've, uh, like I said, I've developed my, my system based on the, the, the readings we get from the, take it out on and home automation. Um, but it's, it's got a lot to be desired as well, but we're making due. Um, so the, how, how is it handled? Like if you wanted to feed one strain differently in, in, in the same room or maybe there different harvest groups going on in a room, would you actually feed those, uh, zones differently based on your, uh, water content reading and.
Just real quick, mark. Just wanna let you know, we're gonna have a whole episode dedicated to, uh, the open sprinkler integration. Very, very soon. We're gonna be making that announcement soon. We're working hard at work on it. So I just wanted to clarify that. And then Seth and Jason, I don't know if you wanted to speak to his question
anyway. Sure. Absolutely. And you know, the answer is yes. Uh, if you have the energy to be able to steer crops differently in a room that is multi cropped, then, uh, your plants will reward you with that, that type of dedication. Um, at some of the larger facilities, we see that they just have too much complexity to be able to manage some of that stuff. Um, and as far as the, the details in the open sprinkler itself, yes, you can run different irrigation schedules for, uh, different zones.
Uh, the wonderful thing about the array integration is, you know, we're, we're mapped our zones directly to the channels on that open sprinkler. So, you know, you have a, a mapped visual of which zones are, are related to which harvest group you can change the timing on each of those harvest groups as well. So maybe we have, uh, one set of plants in there that prefers a, a shorter generative, uh, cycle.
And a longer bulking vegetative cycle then, uh, then you can just map that out even before you get that, that plant started and we're gonna up update the irrigation schedule when each of those different harvest groups land at that point in the plant life cycle. Great. Well
done. Awesome. Thank you, mark, for your question. Um, yeah, it's popping over on YouTube. So I'm gonna get to get some of those questions. Hoffman's choice from Detroit rode in. Do you guys have any irrigation guidelines for freshly transplanted plants in order to invoke root production? Currently I water every four hours until I see some real dry back and then I change any advice. Uh, you know, that's, that's not too bad provided you're putting on very, very small shots at a time.
You know, typically what we want to do is after transplant, give that plant one to two very small shots per day, as we watch that water con that volumetric water content line fall. So basically we don't wanna bring it back up to field capacity until we've achieved a pretty decent drive back typically about what we'd wanna see in our generative steers.
So that 15 to 20% minimum, but the key is we're giving it fresh water every day to keep that root zone aerobic and not suffer any damping off or root rod issues that'll happen. And you know, the other thing you remember too, especially if you're transplanting, you know, on top of slabs or unit blocks, plant roots, don't know what gravity is. They don't know to grow down.
They follow the path of water and they follow the path of water by following the air that the water sucks in behind it, into the pours in the media. So we have to give those plants or those roots, a path to follow. If we don't. Typically is not gonna be a very stimulating growth into your transplant media, especially if it's on top. And we, you know, we just wanna make sure they're healthy and fresh the whole time. You don't want to just neglect them for two weeks or a week.
Yeah. So I just gonna say the same thing basically in different words. And one is, um, those daily irrigations are encouraging, uh, plant growth. They are simulating the growth of the roots. Uh, when we overwater our plants are gonna get lazy and they're not gonna seek out that lower media and mean Gulf fit as quickly. Um, and, uh, if we underwater, we're just gonna stunt the growth of the plant. So it's the happy medium in between there.
And, uh, you know, and it sounds like you're on a pretty good path, uh, to doing that. So usually we just call it a dry down segment, uh, while we're rooting in. And that is, you know, every day we wanna see the overall water content decrease after transplant. We wanna make sure we do get those irrigations in there on a daily basis. And once we see that, uh, that water content hit a say, 15 or 20% decrease from original transplant, then, then let's move into some generative steering.
Yeah. What I can say honestly, is that was something that was always a little frustrating without, uh, without monitoring equipment. You know, it seemed like some plants had be nailing it on and then a quarter the table, like they're way overwatered, you know, and now I can actually quantify that and say, all right, across this veg table, let me put on this small shot that I know is not gonna overwater any of these plants.
And I also know that I've got a few days where I'm still just gonna be putting on those small shots and chasing it down. And, you know, without the tools, it's really, it's a lot harder to have the confidence that you're doing the right thing, you know, especially if you can't look back and say, Hey, that's where we messed up last time, even though we're trying to do the same strategy. It's all about having the tools to do your job better growers also.
And we had another question coming over on YouTube. Lou wants to know can, and should your sensors be calibrated to a specific soilless substrate per meter group's directions in order to achieve plus or minus, um, accurate one to 2% accuracy, especially in cocoa. Um, for example, based on its use of substrates, uh, dye electric properties, does the sensor account for the difference between the makeup of a hor grow purchase, uh, versus Dutch Plantin, cocoa pot, smaller, uh, larger sizes of cocoa.
Sorry, that's a lot in, uh, one question, but, uh, I can repeat it if you.
Um, so from our opinion, it's not worth doing a specific calibration between, uh, two different types of, uh, soilless medias, especially if you're within cocoa, um, or within rockwool or within a cocoa Pete per light makes any of that type of stuff. Um, and, and the reason is, is mostly because it's gonna be hard to see that amount of accuracy, even between sensor installations across the facilities, right?
Mm-hmm so that last, you know, one or 2% that we might gain from being specifically calibrated, we're not gonna be able to reach that with the, with even a great sensor installation. Um, and the. I guess stepping back and, and taking the, the whole value of it is really looking at the time series data as well. So we've got a population of plants.
We've got sensors in a sample of that population, uh, that sample, you know, even at some of the best growers, I'll see, you know, 5% variation from, uh, top water content to bottom water content in, in those samples. And so, uh, I guess, uh, from my standpoint, um, you know, without trying to, trying to, um, get too offensive is just that there's energy spent better elsewhere.
Yeah. I, I mean, I think you brought up an important point. Jason, when we're looking at this room, it's, it's dynamic. We don't have a set value for all the plants in it. And that's why, you know, whenever we're talking about like water content values for crop sharing strategies, especially in terms of dry back, we're always patting everything with about 5%, if not a little more. And actually it's gonna depend when we go and look across your room.
If, uh, you've got five sensors in there and five benches and you run out and take 25 spot measurements, and then we discover that, Hey, you got about 10% variance on each bench. Those are the parameters we have to work in. At that point, we know that based on our one sensor that might say 50%, we have another plan at 40%. So we've got a plan for the best worlds for both. We're playing a game of averages at the end of the day.
So, you know, just like in statistics, when we see one outlier, sometimes it's initially concern. But if we look at the whole and what we're actually able to treat practically, then we can kind of dial it back and say, okay, that one to 2% may not be the most important thing. And one thing to remember too, um, you know, there, there is a certain amount of, uh, user skill involved in using some of these like highly precise, scientific instruments.
And I say precise and not accurate because accuracy can come down to that user skill. If we want to go back. 2030 years, we could be using only soil moisture potentiometers and I can give you a pot that I know because I weigh it dry and I put X amount of water in it, and I know how much water's in there. I can give it to you. And I guarantee the first 10 or 20 times, you're not gonna get the right value because that instrument's difficult to use.
There is a large amount of user skill involved in attaining that and what we've got here at Aurea, you know, at the tariffs, 12 is much easier to use than anything that's existed historically. However, um, that doesn't mean that it's super easy. That doesn't mean it absolutely works. If you just jam it in, you know, these probes are designed to be in constant contact with both media and water.
Well, if you don't put it in far enough, or if it scoots out a little bit, or if we happen to have some inconsistent media with a big hollow spot, um, if you're still using perlite as a big crutch, there's a lot of things that can really make it, um, difficult to get an accurate reading. And it's important to structure your processes around that.
You know, just little things like if you've got the terrace 12 and the sous, you know, for a second, if you're running around and worried that, Hey, my sous readings are always a few percent off. What my TAs reading is in you. Okay. Well that terrace reading's been in there for a few months with roots growing around it, your sous you're jamming it in every time you're each installation is opening up a possibility for a variable in your own processes and inaccuracy.
So you've always gotta look at like, yes, we've got accuracy and precision and data. How precise are. The things we're measuring, because if we looked at that table, you know, we're looking at precision it's how close are your measurements to each other? Well, if your table itself, isn't very precise, you can't expect to get very precise even with the best tools.
Yeah. And, uh, absolutely. You know, if you've got your drippers, uh, within 1% of each other, if you've got your clone and plant growth rates, as consistent as 1% within each other, then, uh, then you're on top of the game. Um, you're, you're the absolute best in the industry. If, if that's that's the level that you're at and we're always working to, to make our stuff better calibrated in different dialectic medias.
Yeah. I'll be perfectly honest. If, if you're down to the point where 1% matters to you for volumetric water content, or you feel that it does in your performance, you wouldn't be here listening to what Jason and I have to say, you'd be rolling in your money and on vacation probably. Maybe, I don't know, that's the dream, right? If you're successful. awesome. Thanks for that. Um, Lu said thank you very much. Makes a lot of sense.
Um, that's the last question over on YouTube for now, but uh, you guys keep sending those in back over to you, Kaisha. Thank you, Mandy. Yeah. Thanks. YouTube said drop those questions to over to us so we can get 'em answered, but we do have a couple of our attendees here with us. Dropped a couple questions in the chat. Billbo you wanna go ahead and unmute, unmute yourself and ask your next question. Okay. It's probably a repeat.
Are you going to add leaf surface temperature readings to your platform?
Um, you know, over the years we've had a ton of requests for it. Uh, since leave surface temperature is usually fairly constant in reference to room temperature, as long as other variables, aren't changed such as light type as we discussed earlier, uh, typically you can infer and, or make the same decisions with a room temperature.
Um, so we don't currently have any plans to release a leaf surface temperature in our, in our interface right now that doesn't mean that we won't at some point in the future, we've just, uh, we've got some, some other goals that we're, we're staying focused on.
Yeah. And part of that, can I add to that? Um, why Jason brings that up is if I was out there taking temperature, leaf leaf temperature samples all day, am I getting a more accurate VP D at, you know, right around the leaf? Sure. But if I go do that 20 times and I watch my VPD on the meter, I know that under my conditions in this amount of light, this VPD number means this leaf surface temperature.
And that, you know, as far as Jason talking about being steady state, that's kind of reflected when we look at VPD charts, we're always correcting for leaf surface temperature and we're doing air VPD. So almost any quick chart you look up, you're gonna be able to reference like, okay, are we plus 1, 2, 3, 4, or minus 1, 2, 3, 4 on leaf 10. So it is important, but the actual number that you're adjusting your system. The things that let's say your HVAC system can sense is not leaf surface VPD.
So we've gotta take that and transfer it into a number that we can actually work with.
Yeah. And, and kind of just thinking about how, um, leaf surface samples are taken right now. Um, Most commonly is done with the infrared thermometer. Uh, one of the things that I loved doing as a cultivator was actually taking a thermal camera in there, a and checking out the dynamics across the plant, as far as leaf surface temperature went.
So instead of having very small point measurement, I could capture a whole plant or a whole canopy and, and check out all right, here's the temperature of my buds, where I'm not getting transpiration. Here's the, the top level temperature of, of my plants, which one, which are the ones that are getting the most radiation from the lights. And, and here's the temperature down lower. Um, also fun to check out, uh, check out your planters with that thermal camera.
You some sometimes see that the water flow, just because of the changes and temperatures of irrigation from the drippers. Uh, I was able to catch a lot of clog drippers and emitters because of the thermal camera. I could see that, Hey, the left side of my planter is not getting cooled off for my, from my irrigation systems. Um, so if you know, you have the, the resources to do so in the time and interest, uh, go check it out.
You can definitely learn a lot about, uh, your plants from, from doing that.
Yeah. And that's a good point too. And we're trying to dial leaf surface temperature. We wanna look at, you know, the leaf surface temperature across the plant as well. If we just dial into those top nugs, then our bottom Lu nugs, probably aren't gonna look too great. So we really wanna look at that whole plant and say, okay, what are we equating to? You know, at this level of light exposure and least surface temperature. Do we have a less mature bud, farther down?
You know, that's something I've noticed over the years. If you've got a nice purple up top and then pretty deep, pretty quickly you get into the green. Well, that might influence some decisions down the line where you can go back and say, Hey, with the thermal camera, I can tell when I've got too thick of a canopy too thin, too deep, you know, and really just, that's taking it from a single point measurement and making it way easier to get in all that information at once. Awesome.
Thank you for that question, bill Bo, if you have a follow up, please, you posted in the chat. Uh, we're gonna move on to Nathaniel's question. Nathaniel, you wanna unmute yourself and ask it? Or would you like me to ask for you? No, I'll go ahead and click this one. Excellent. Um, so just to bring it back to some, uh, the crop steering topic, um, for basically for every, uh, automated control system manufacturer out there, there's a different crop steering, um, technique, uh, that's published.
Um, and so my question is what, uh, if you guys could, you know, um, discuss a little bit about the different theories on crop steering techniques, uh, the two examples that came to my mind, um, were the two opposite extremes of, you know, one suggestion is at different phases of the plant's life cycle. You may want to have a dry back down to 20% of BWC, uh, and then all the way up to, uh, um, saturating the field capacity. Um, whereas the, you know, opposite side of that spectrum.
Is to maintain just static water matrix, tension of a consistent 40 to 50% VWC throughout the life of the plant. Um, can you guys speak a little bit to that?
Yeah. Um, and I, you know, I think probably the biggest differences that's coming from these manufacturers is just the, the details of it. Uh, I'm hoping that everyone else is pretty close to where we're at as far as how the science actually, uh, affects plant physiology. Uh, I know that, uh, some of the, the largest rockwool manufacturers, um, I'm not gonna name in specific, but the. Probably the ones that are original, you guys are most familiar with.
Uh, you know, they've been used in peppers and tomatoes for, for decades and decades. And, uh, uh, you know, what we recommend is exactly in line with what they recommend. Uh, they've done tons of research as far as massive production, um, in those greenhouses, in the Netherlands. And, uh, and so I, I think the best idea is to, you know, take the science behind it and learn the science.
And as you know, we mentioned all the time, it, when we say it's strain dependent, um, there is gonna be different techniques for the different plant genetics. And, uh, and so the best way to do it is learn on how those controls affect the plant, uh, rather than just going by a template recommended from, uh, some company or supplier.
Yeah. I, I think it's important to remember that these techniques really are a set of tools to go in your toolbox, to apply at times when you need 'em, you know, you you've gotta learn when to use what type of screw. That's something, you know, someone can give you the toolbox, if you are not proficient in using those tools, you're not gonna be able to get it. And then another thing to really kinda look at is I'll use liquid versus salt nutrients as a great example.
You know, if we look at feeding schedules for the same product, liquid versus salt, usually the liquid's a little lighter. Um, it's not quite as aggressive. Um, basically when you look at those feeding schedules, we're looking at what can, we're gonna design a schedule. That's gonna be reasonable for the person to accomplish with the tools they have.
So if you don't have high precision tools, like there's a few crop screen guides out there that I've seen that aren't, aren't quite as tight as some of the parameters we look at. But if I were to step back and think, Hey, I'm writing this guide that hopefully anyone can do and not fall flat on their face. I'm gonna be super conservative in that guide and make sure they don't fail.
You know, I mean, again, like if we go out to, if we compare to nutrients for most people at home and in a smaller facility, Liquids are easier for them to measure, you know, if I'm only mixing up two gallons to feed my plant every day or so, every couple days, my big plant, uh, maybe I don't want to go spend money on a scale that would be appropriate for me to be accurate there. Well, liquid nutrients are really easy solution. I can get my little shot glass.
That's got my graduated milliliters on it, fill it up to where I need to be. Boom easy. Whereas yeah, maybe I don't want to go spend a hundred, $200 on a scale. So I think that's really important to remember when you're looking at some of this information coming out of different manufacturers, you know, uh, one, one name names, but I've seen one great crop steering guy from a company that doesn't sell any sensors and, uh, you know what, they have a lot of the same science behind it.
But if you look at that, it's got a lot of padding in it to make sure that, Hey, you might not get as aggressive of results as you would as aggressive, aggressive as results as you get with, uh, high density sensor population, but you're getting an improvement. Just only watering whenever you feel like it or not having any, you know, rigid schedule at all.
It's it's why you'll see us, uh, us on here kind of scream get a little squirmish when people ask for exact DC numbers or exact room temperature numbers, there's just so many other variables in play that, uh, that sure. We can give you a reasonable range to start with. Start within that range, makes modifications, document those modifications and, and then make a AB comparison. Um, obviously the, the key there as well is don't change more than one variable if you have any opportunity to do so.
And you want to make an improvement on there. Um, the challenge of that in reality is a lot of times we don't mean to change a variable. It's just hard to operate a room exactly the same for 60 days. Uh, and this is especially true in greenhouses it's, uh, It's very challenging. Especially somewhere we have four seasons, like up here in, in the Northwest. If we wanna do AB testing, we can try as hard as we want not to make a change to, to a certain variable.
Um, maybe we're analyzing a nutrient, well, this month, that average temperature was 60 degrees. And last month it was 70 degrees and nighttime differentials were, uh, you know, they're 10 degrees higher right now than they were a month ago. Um, and obviously we're doing everything we can to combat that with, uh, greenhouse controls. But, uh, it, it, it's not at the scientific level, it's at a, at a production
level. Oh, absolutely. And I think, you know, one thing that I, I see a lot in the industry right now is, um, we're all, we're all going so fast paced. Everyone's trying to make it, we're trying to survive, trying to grow business. Uh, so it's very tempting to try to deal with. Tomorrow's problems, today's problems in yesterday's problems. But what we really need to do is look back and deal with the problems that happened two months ago, when we're about to repeat that cycle.
So if we're talking about like, like say EC coming into ripening, I can take the same strain and show you it at two different ECS and then show you in the jar, smoke it. You couldn't tell me the difference. Now there's a lot of factors leading up to where we're gonna be with that EC and ripening that contribute to it. And if we didn't look back at anything before ripening and say, okay, where was our EC at what time? What kind of ranges were we seeing? How slow did we stack up?
How slow are we tapering? If can't look at all that, then we really can't extrapolate much. Like if you've got Herms in week seven, you're just throwing bananas, like crazy. And, uh, you know, you don't, you can't figure out what changed. , but you're only looking at that week's worth of data compared to the last time. And you're not looking at everything leading up. You just, you don't have the complete picture.
This is, this is the, the basis of why we created harvest group recipes. Uh, take, take a data set. Here's what we plan to do. Here's what we're trying to do. And, uh, then we run a harvest group analysis, jump into our production page and check out the harvest group analysis. Here's how many days that you are outside of your intended parameters for easy or relative humidity or any of that? Obviously, if you you've nailed it perfect.
Now you can maybe dial in those target parameters even just slightly more. Um, and then that's where continuous improvement comes from is how tightly can we operate within our plan. And do we need to adjust the plan if we are operating tightly to that plan? Uh, obviously if we're doing everything we can just to. Be close to what we intend to do is it's gonna be really hard to make improvements on what we intend to do.
Nathaniel, did we address everything in your question, in a shout out to you? Thank you for dropping. You dropped some, uh, an article here and a chat, um, love the resource sharing, but yeah. Did we cover everything that you wanted to know? I, yeah, that, that totally makes sense. I mean, I, it, it absolutely is.
Um, uh, you know, pretty clear that, uh, manufacturers are gonna make the most generalized wide applying, um, uh, advice that they can give with the least amount of failure and the largest group of people, which is their customer base. Um, and every iterative aspect after that is going to be, um, based upon your, your own personal experience. I was looking for, um, uh, I suppose a bit more.
Uh, introspection into your experience in your own R and D. I know me group has, uh, OROYA has their own crop steering, uh, program as well for that same purpose. Um, uh, but I was looking for, uh, a bit more insight into, um, the, the effect of dry back levels are different stages. What you guys see personally in your own work. Um, I is effective.
For example, I, I find that a static, um, uh, water matrix tension within the 40 to 50% consistently without hitting 60, 70, 80% video VWC, without going down to 10, 20% VWC, keeping that static with just a couple points, um, of fluctuation for, uh, for crop doing at different phases. But the vast majority being that static, uh, level is the most effective across the largest, uh, group of strains. But I was hoping to hear what you're.
Personal experiences were within that as well, rather than the explanation of, um, this is why manufacturers do it this way. Gotcha. And yet real quick to the point of the, uh, uh, uh, flowering plants are GRA Tropic, um, the, uh, the AMPL organelles inside the, uh, Mari thematic root cap, um, it's filled with starch and heavier than the surrounding cytoplasm causing it to sink inside the cell, which is what signals gravity for the root grow downwards.
So, yeah, roots, roots, and flowering plants are gravity trophic. They do know what gravity is they do, but they don't have to choose to grow down. If I put a plant in a tube and I give it mesh on the outside of that tube, I can get air pruning, cuz those roots are gonna seek out the path of water and where it's at in the media. So you're, you're totally correct. But in application, that's why we're seeing like, you know, that's why your roots grow sideways in the slab. Water's wicking that way.
That that's very, yeah. It's not a hard, fast rule. Yeah. Well, and it, what you're saying is totally correct. What we're talking about here is using that water flow and introduction of grab or oxygen into that poor space to stimulate Ruth root growth. Um, as far as, uh, keeping it static like that, I, I get where you're coming from. Um, that's almost going back to like deep water culture where we're keeping a static saturation point.
We're keeping a pretty static sea point and we're just introducing oxygen all day by keeping it into that. What we're not doing though, is putting any kind of, uh, generative or respiration stress on the plant. So like if we're watering just in the morning, we're depriving that plant of fresher oxygen the rest of the day.
And when we're talking about dry back, That dry back percentage is a reflection of, you know, your heat and humidity in the environment that VPD and how much transpiration we're getting from the plant.
So there is no hard, fast rule on how much dry back comes in that really has to do with, uh, what kind of media you're running, you know, with rockwool point, I, I did really appreciate your, your acknowledgement of preventing anaerobic, uh, uh, bacterial development in the substrate as well through this method. So that, that was really good insight. And that's, that's something too. I have to stop myself.
Sometimes I'll get hung up on, you know, a little, a little detail, but then when you break it out to production, um, it's, it's kind like, you know, when our transplant dry back, like, yeah, I wanna see that 15 to 20% dry back before we hit it with a P one, cuz I need to know we're clearing that, that poor space and giving those roots oxygen enough that they can grow. However, I know that I can't just let those go anaerobic over seven days, right?
We've always gotta find that, that medium between, uh, the cool stuff and science, and then actual on the ground application. You know, like if we were talking about, uh, oxygenating your water to feed your plants, that's great. You know, if I follow down that road too quickly, suddenly I'm at 70% per light mix and, uh, really wasting a lot of water. So, you know, we we've gotta find that medium.
And as far as, like I said, those dry back percentages go, as long as we're seeing that 10 to 15%, that means we've got a healthy amount of VPD to promote good transpiration and good plant growth. Um, keeping it in, especially if you're in a soilless medium, you know, our matrix potential is very low. The plant doesn't, it can't really sense a difference between 50 or 40, right. It's very available there.
It can't sense down to 30, when we're talking about cocoa and rockwool, it doesn't get difficult for the plant to start pulling out water from the media till we start to approach that wilting point, even if it's temporary wilting point. So as far as keeping it static, I think that the biggest difference would be looking at like, in that static 40 50, like I said, that's close as close as you're gonna get to deep water culture with some particles around the roots.
And then what we're talking about is really being able to in, uh, increase that amount of time that you're depriving the root zone of oxygen and not depriving, but you're not introducing anymore. You're not giving it that little stimulation to grow. Yeah, thank you so much, man. I really
appreciate that perspective. Yeah. And just to kind of go back to that, you know, the low end of those water contents, um, when we talk about the major potential in something like rockwool, uh, it's very linear, uh, down to about zero. Uh, one of the very first sensor installations that I did after joining on with meter group, I, we did back east and, um, that next day we had flown back and I was checking their graphs.
And here, here we were at like two to 5% and most of these plants and I, I called 'em up and I says, what's what's going on? And these things all dead. And they, they took a picture and sent it over to me. And I couldn't, I couldn't believe my eyes, the, the plants had available water until that substrate was completely dry, obviously.
That strategy is not realistic in order to run an entire cycle, because we are gonna see the degradation of the rock wall through doing that, to, to that substrate. And obviously it's gonna be much more challenging to manage our ECS. Um, and we would need a much, much larger substrate once our, our water holding capacity has, has dropped that much due to low water contents.
Yeah. And, you know, honestly, to build on that a little bit, one important thing to remember is in, you know, plant tissue production, we've got water light and CO2, you know, EC nutrients do play a role in that, but those are three main inputs. So if you know, we're driving, let's say incredibly hard drive backs to the point where we're really stressing out those plants. If I look at that over the whole cycle, and I say, look, I needed X amount of light.
I needed X amount of water and I needed X amount of CO2 to produce this plant. And that's, that's throwing out heat, nutrients and everything else. I can start to quantify that and say, Hey, look, I actually, by pushing these huge drive backs ended up giving that plant a lot less water in a time period where it actually needed it to develop the structure it wanted, or it needed to grow. Cuz when we, when we're steering these plants, we don't wanna stress.
'em so hard that we're like, uh, you know, reducing production. We're just trying to steer it through hormonal changes. So like during stretch, we don't, we're not trying to torture those plants and make 'em grow less. We're trying to focus that growth on increased bud sites, increased stem diameter, and we're really promoting a better, uh, PGR balance in there so that, you know, we don't have, like, let's say this high oxen production state, which is normally what we see in stretch.
That's causing the plant to stretch. We, we want functional structure, not just. Lumber . Jason: Yeah. I, I know historically that, uh, a lot of people talk about stressing their plants for that, uh, that hormonal purpose for the, the indication to modify the plant morphology via physiological cues. Um, and I like to think about it a little bit differently. Not necessarily stressing it, but, but guiding it. Um, and it, I, I, we always talk about a little bit about the weight lifting comparison.
Right. You know, if, if, if I am, uh, if I'm doing some, some heavy, low rep lifting, then, uh, that's gonna be like generative. If I'm doing lots of lower weight reps, that's gonna be a little bit more like vegetative. Um, if I go so heavy that I hurt myself, I'm not gonna be lifting much at all for a. Yeah.
And I think, you know, one thing that honestly, some of the terminology in this industry has gotten a little or pushed a little far, like when we're talking about plant stress, we're just actually talking about plant responses and the easiest way, I think where that term came up is to say, Hey, if we're depriving something or we're, you know, doing something that's, doesn't seem normal, it's gotta be stressful. Right?
Well, yeah, it, it might not quite be stressful in the way that you're thinking, you know, much, much of the way that I always, uh, kind of bash flushing here. And that's mostly because of the term around it, you know, that really in the industry has come to me like, Hey, we are watering this until we literally mechanically flush all the salt out now, you know, in application, not everyone is talking about doing that.
some people are just talking about reducing their nutrient input and slowly bringing that EC down, which is what we want. But you know, you want to avoid that confusion. Wow, what a great conversation, Nathaniel, thank you so much for your question. Um, Mandy, I'm gonna send it over to you because I think we've gotten some YouTube questions in. Yeah. Yeah. We have. Thank you for that discussion guys. Um, Diane's hanging out with us over on YouTube.
He wants to know, um, straight cocoa or cocoa and Pearlite in your experience. What's the better medium.
I, I mean it, I say this quite a bit and I, I like cocoa a lot straight cocoa for me has been consistent forgiving. Um,
yeah, if you have, I mean, honestly, really where per light comes in for me is, uh, you know, it's something I used early on, not just my canvas cultivation career, but gardening in general, uh, before I knew how not to overwater my plants. So if you've got a sensor system, um, don't, don't waste your money on Perla. You want that bigger gas tank that the straight cocoa offers, you know, with a cocoa Perle mix. Typically we'll see like 35 to 45% max VWC.
What that means is I, I can't run a, a 30% dry back if I only hit 35% volumetric water content. So that's kind of where it comes in. On the other hand, if you've got a big pot and, uh, you're bringing a small plant in it that per light's probably gonna help save you from overwatering by holding a lot more oxygen in the root zone. Honestly, the biggest difference that I've seen is, uh, you're gonna go with a smaller pot with straight cocoa.
You're gonna have the ability to anyways, and again, especially if you have monitoring equipment, if you can see what's going on inside there, you can really avoid some of those, you know, blunders that are easy to make when you're just staring at of pot. Wondering how dry it is. Awesome. Thank you for that. And, uh, John wants to know. So I'm switching to pure Cana, Coco with no crutches. This next run I'm running in two gallon pots, um, is 0.08, four way. Drip going to be enough.
Yeah. If you're, well, if you're, if you have enough pump I built a system before where it takes me, you know, I don't actually get point a, it takes a little longer, so just make sure your specs are, uh, you've got enough pressure and flow for what you need. Awesome. Thank you guys for that. Yeah. Back over to you, Kaisha. Awesome. Thank you. I love when we already know the answers just yes, that's cool. All right, Billbo dropped another question in the chat. Go for it. Billbo okay.
Scrolling up has leave service temperature, been correlated with the model conductance. And is that why you are potentially. Not going for the leaf surface temperature.
Um, so I, I would probably prefer just to talk about the relationship with VPD, um, simply because leaf temp on its own, it isn't enough information to estimate, to model conductance. Um, and that's why you'll hear us usually talk about VPD in relationship to small conductance. So as an easy measurement, VPD is the best way to estimate your store model conductance. Um, and it's gonna be kind of some type of.
Curve some type of bell shaped curve where we see that stem model conductance is highest typically, um, depending on the life cycle of the plant, you know, between say 0.7 and 1.5, uh, BPD, if you will, uh, when we're lower than that, there's so much moisture in the air that, uh, our, our plants aren't necessarily transpiring as fast as they could.
If we go up above those rates at the high end, then the plants actually gonna close its mates a little bit in order to retain water and not go directly into wilting.
Yeah. And much like R H and VPD. It's just important to remember with, to model conductants and leaf BP that we're looking at two, two separate ways of looking at, uh, the same problem. Right. So before we have, before we can measure to model conductance.
The, uh, you know, the easiest way to do it back then was leaf surface temperature with air P D. I can calculate then what my approximate model conductants can be based on how much pull, how much vapor pressure deficit I have and how much the plant should bring up through X amount of Leafs leaf area. Now that I can directly get that in micromoles of water coming out of the leaf, like they're just two different measurements for a similar thing.
So I would say a good way to equate those two would be, you know, if you used to use soil moisture, potentiometers in the, in ground to measure, you know, how much moisture you have in the soil, is that accurate? Yes. Does it give you a percentage? You're inferring something from another set of numbers in another set of units. That's the big difference there. Otherwise we're, we're really talking about something that's approaching the same goal.
We're looking at leaf surface temp or to model conductance.
Yeah. And obviously, you know, when we say VPD related to system model conductance, that is with all other variables consistent, right. That's at the same point in time, uh, same plant type, uh, same nutrients, uh, same light quantity, same CO2 levels. Uh, obviously if we make adjustments to any of those, it'll change the relationship that we see between, uh, the surface temp and, um, or stone model production, excuse me. And
BPD. Yeah. And that's where, you know, if you're dealing with, uh, any kind of variation there, like, let's talk about the greenhouse where we've got varying amounts of light and thus our leaf surface temperatures varying throughout the day. You know, if I'm trying to just use that leaf surface, temp and BPD to calculate my watering needs. Yeah, I'm not really gonna get very close in a greenhouse setting.
I might have a very wide estimation, but pretty much every day I'm gonna go back and be like, wow, there's a little extra in the tank than I expected after today. Or, yeah, it went dry. We missed the last water. you know, just trying to keep up on this, if I'm following the graphs with my irrigation needs throughout the day. Awesome. Thank you so much. All right, we got one more question from Laura, Laura.
I don't know if you wanna unmute yourself, but I feel like this is a good one to take us home. Hey, just wondering if there's a scientific definition for crops
during, um, phasic parameter
modulation. Yeah. I was gonna say manipulating your environment to promote a certain plant morphology. Um, I, I think, uh, Before it entered the cannabis space as much. We just called it, uh, growing intelligently to get the type of product that you want. Like here are the practices that we have to do.
You know, if we're talking about grapes, for instance, thousands of years, people have been going out and pruning flowers early in the season to promote better grape production that's crop steering. You know, people have been manipulating irrigation for thousands of years. All of that is crop steering. But if we wanna talk about it scientifically yeah, just manipulating the environment that a plant exists in in order to produce certain growth results, desired growth results. Thanks a lot.
You guys, thank you for your question, Laura. All right. And our final minute, Seth and Jason, anything else you wanna tell everybody before we sign off today?
Thanks everybody for joining. Uh, and we, we really appreciate our audience contributing to the questions in these. And, um, for us, you know, we're always trying to learn more about this stuff when we get harder and harder questions. Uh, I always enjoy trying to learn up on as much as I can about them before an episode and, and, and provide at least the best interpretation I can, uh, on the subject.
Yeah, absolutely. I love, I love being able to touch some of those things. Like RuBisCO was fun. Haven't talked about that in a few years. . Yeah. Awesome. Yeah. To our community. I mean, this is for you and we thank you so much for all your questions. We got a lot of commission, uh, questions submitted this week that we weren't able to get to. So we're gonna put those off until next week's show. Um, but the live questions, that's the best way to hear from the experts.
So thank you to everybody who submitted their questions either here on our Hangouts, around YouTube and Seth and Jason, thank you for dropping the knowledge man. Like, wow. I learned a lot today. Um, uh, and Mandy, my partner in moderating, couldn't do this without you. Thank you. Always. Awesome. All right, folks. Well, thank you all for joining us for aro office hours. This week, we do this every Thursday. The best way to get answers, like I said, from the experts is to join us live.
If you have any questions about aro, definitely book a demo, and the experts will tell you about how it can be used to improve your cultivation production process. But as always let us know if there's a topic you'd like covered in a future, offers our session posted in the chat, shoot us an email at support.aroya@metergroup.com or send us a DM over Instagram. We definitely wanna hear from you.
We record every session so we will email it to everybody in attendance, a link to the video from today's discussion. And it'll also be on our Aros YouTube channel, like subscribe and share while you're there. And if these conversations are helpful, please do spread the word. Thanks everybody. We'll see you next time. Great meeting guys. Thank you so much. Thank you, Nathaniel. Good.