Subscribe
Share
Share
Embed
Seth Baumgartner and Jason Van Leuven open the mics for your crop steering and cultivation questions.
Kaisha [00:00:04]:
You. What is up, gromies? Welcome to aroya office hours, your source for free cannabis cultivation education. I'm your moderator, Kaisha. This is episode 94. If you're on the hangout or checking us out live on YouTube or Instagram, be sure to drop your question in the chat. And if it gets picked, we're going to cover it during the show. Seth, Jason, gentlemen, how are you doing today?
Jason [00:00:29]:
Doing well, doing great.
Kaisha [00:00:31]:
Awesome. Okay, I'm going to get right to it. This is a great question. We get a lot of questions about ph. So kootenay craft cannabis dropped their data with us on Instagram. Feeding 4.0 ec and ph 5.9. Ph stable in pipes after sitting still at 5.9, plants are very healthy. Cocoa one gallon bags day 25 substrate ec seven at full saturation.
Kaisha [00:01:00]:
Runoff EC nine runoff volume 500, ph is 5.2. Any thoughts on why runoff ph is low? What actions, if any, to get my ph closer to my feed?
Seth [00:01:13]:
Ph? Yeah. So I think probably the best place to start here is a little bit of a definition of what ph means in the root zone, right. So ph as a base, we're looking at the concentration of positive ions in solution, hydrogen ions specifically. And when we put different salts into solution, they dissolve, dissociate, and now we have positive and negative ions floating around in solution. So pH is really looking at that balance between positive and negative ions. And the more positive charge we have in the solution, the lower that ph number is. So the reason that ph number drops between input water and runoff water is because while the plant is sitting in that solution all day, it's pulling up. Specifically at night, it's pulling up more, it's pulling out negative ions.
Seth [00:01:59]:
Most of our plant essential elements are negative ions once they're in dissociated form from salts. So that plant as it feeds is constantly shifting that solution to have a more positive charge because it's pulling the negative charge out of it. So if your plant's feeding at a healthy rate, we should see a little bit of a ph drop. Now, over time, as you're building up EC in your substrate, it's important to make sure you're getting enough runoff early on. So if we want to build EC, but we cut off runoff for like, let's say seven days, there's a good chance that although we're building EC, we're building a lower ph solution because that balance isn't correct. So your best approach is to usually feed heavy, push a little more runoff. If you're at a 30, sometimes bumping up to a 35 to help refresh and replace and reset that ion balance in the root zone.
Jason [00:02:53]:
And really, from a plant's perspective, the reason that ph is so important is because it affects how those different ions are uptaken and metabolized by the plant. Right. So when we take a look at nutrient availability, it is actually somewhat affected by our different ph levels. I love looking at the charts on the Internet as far as the solubilities of our macros, our micros, and getting an idea of, all right, well, when I'm at this specific ph, I am kind of just trying to wager what is making most nutrients most available. All right. And so as we go lower in ph, certain nutrients are going to be more available to the plant. As we go higher in ph, a different set of nutrients are going to be more available in the plant. And so we're always trying to find, hey, what's that happy medium that allows us to basically balance its uptake in the system there? And so at 5.2 ph, yeah, you're just a little bit low.
Jason [00:03:53]:
And I think I would follow Sus advice here just perfectly in looking to correct it. Obviously, if you do that and you aren't getting quite the results that you wanted, you're not seeing that rise up to the 59 on your feed, then you might think about, all right, maybe my nutrient balance isn't quite right. If it's something that you're mixing up yourself, or you're not following the manufacturer's instructions, or you are following the manufacturer's instructions, then you might think about just adjusting some of those ratios a little bit and see if that doesn't help the balance of cations and anions and solution on that plant.
Seth [00:04:32]:
Yeah, I wish we'd prepared a chart for a visual because it really is cool. When you look at all of those different availabilities lined up in a visual chart, and you can see why we typically want it between five, six and 60. That being said, there are some nutrients out there that are meant to be mixed at, like, let's say a five six compared to a 60, for instance. And some of that has to do with solubility issues with different salts. And it's great to pull up. I think Jason's going to pull up this chart now. It's good to remember though, once we see this, we see tapering availability of nutrients down at low ph and high ph. But at 5.2, for instance, we still have plenty of availability for nutrients to be uptaken by the plant.
Seth [00:05:10]:
The important thing is to keep monitoring it. So when we see that ph drifting low, that's when we really do want to keep making sure we're getting runoff every single day, usually that 5% to 10% minimum of irrigation volume. And that way we can also get a good ph sample. And it's important, too, when you're doing this, to make sure you're irrigating slowly and actually hitting field capacity before you get runoff. So that way your sample actually reflects what's in the block and isn't artificially high because you're pushing water through just to get that runoff.
Jason [00:05:40]:
Yeah, so I did want to just pull it up because, well, Seth and I were both mentioning how valuable that these can be. And one of the things that you definitely want to make sure is that the chart that you're using is applicable for the media that you're in. So if I'm in Rockwell, it's a substantially different ph range for that optimal rather than if I'm in something like soil. And so, yeah, if we were looking for coco, I might throw coco in my search line. Just going to pull up this research gate one because there are usually some pretty solid publications here. So if we see it looks like. All right, well, nitrogen's optimal uptake would be between seven and 75 in this specific range here. I wonder what kind of substrate I'm looking at here.
Seth [00:06:25]:
Yeah, and that's another important thing, too. When we're talking about rock wool or straight coco, those are pre unbuffered media, so we have really good control of what's going on. If you're running a pre bagged mix that does have any buffering capacity in it, that's something to be aware of. You might not have to do nearly as much adjustment with your ph to achieve a stable range just because your media has some buffering capacity in it.
Jason [00:06:50]:
All right, here we go. So this one's from the coco depot. And open image new tab. Let's see if we can get a nice view on this here. All right, there we go. So this one's specifically for coco. And obviously there's some differences among coco, but we got to make some generalizations so we can see. All right, here for nitrogen, our optimal ranges are actually a little bit on the very balanced side.
Jason [00:07:18]:
And so that's one where we're trying to ride right on the edge for phosphorus. We can see. All right, we actually have a steep curve. As we go lower than 60, we start to lose that solubility. Now down lower on the chart, when we look at something like manganese or this copper and zinc areas we can see. All right, well, if we go lower, we have higher solubility, but if we go up there higher, where we might see phosphorus to be very available, we lose out on some of those. And so if we get our sweet little pin out here, we can talk about. All right, what's the optimal ranges for these? And that page didn't let me get my pin.
Jason [00:07:56]:
So actually, we're going to be in purple today, and we'll talk about. All right, so for coco, probably if we run in a range right here, then we're going to take advantage of the solubilities of the ones that prefer a little bit more balanced or a higher amount of basic and the ones that are more acidic.
Seth [00:08:18]:
I think it's important to consider, too, the phase of growth that you're in. So when we're looking at stretch, for instance, those first few weeks and then going into mid bulking, nitrogen is very important. So if that ph drifts too low, we're starting to limit nitrogen, phosphorus, and potassium. Those are our three main plant essential elements. So dropping it down early in the growth phase is starting to limit that. And that's when we see some of those classic lockout symptoms that we've talked about for years where basically we're just making the plant deficient in some of its main elements and it's unable to uptake them. However, later in flower, we still want to maintain a good ph. But if we're talking about week eight or nine and we're seeing that drift happen at a point in time, the plant's life cycle, where it should be feeding less and starting to finish, it's a little bit less of a concern.
Seth [00:09:02]:
But if we're seeing that ph drift in those first two to three weeks, that's when we're really going, okay, there's something either wrong with how we're mixing the nutrients, the composition, or typically haven't been pushing quite enough runoff to reset that balance every day. So over time, we've built up a high concentration of ions or salts in the substrate. But it's not the ones we want. It's the ones we want to kind of push out and replace with some of those fresh negative ions.
Jason [00:09:28]:
Yeah. And actually, one of the things that might also be an option is think about what you're using as a ph adjuster in your system. There are certain chemicals that actually will prolong how well that ph is adjusted for. So in this case, if you are using something like a nitric acid, which has a lot of residual, that stuff will maintain an acidic component to your feed for a long time. So you might move to something that's a little bit less powerful, and same with vice versa. On the basic side, if you're using something that doesn't have that buffering capacity, then choose one that stabilizes your basic component a little bit longer. The fact that you are 59 in the pipes means that that's probably not the first thing to look at, though.
Seth [00:10:17]:
Yeah, there's a few different things to look at when we're talking about ph and solution. Another important one is how are you mixing up your tank? So, for instance, I've worked in places where our groundwater is coming out that we use to mix at 7.5 to 8.2. Depending on the volume I'm mixing up and how much salt I'm loading that up with, I might actually end up putting in a substantial amount of ph. Down is a commonly named product, usually phosphoric acid. At a certain point, that's starting to affect my p value, my phosphorus value in my mix. And another thing to consider, if you're having to adjust your ph quite a lot apart from your input water, are you mixing your salts in first up at like a 7.8, and then trying to ph down from there? Because if so, you're probably going to have some solubility issues. It's going to be hard to really nail that EC or PPM value fully dissolved that you're looking for. So right back to always reference your manufacturer's suggested mixing instructions.
Seth [00:11:13]:
And then don't be scared to call them and ask any nutrient company you're working with. If their product has special mixing instructions, they usually try to include it. And then if your water quality, and not necessarily quality, but like, let's say your ph coming out of the ground is quite high or quite low, it's always a good idea to consult that manufacturer and say, hey, what would you guys do in order to mix this properly and make sure that all of my nutrients are getting dissolved and I'm not having any unintended fallout or ph swings. The chemistry on it isn't super complicated, but these companies do put a lot of effort into their r and D to try to make sure they figure out how to use these in every possible application they can get into. Right. They want to make money. So that's probably one of a very good thing to research. And we don't know from this question what the input water ph is like, but that's just another thing to keep an eye on, because especially if you've moved from area to area or you're moving building to building.
Seth [00:12:11]:
That's part of why we see, like, ro being so popular in commercial installations, because sometimes it's easier just to strip everything out than to try and deal with whatever particular problem you have there. Like, if you've got a really high carbonate load, like, okay, do we try to chemically buffer that out, or do we just filter it and have full control? And that turns out to be maybe not more economic in the end, but sometimes just easier in terms of effort, input, labor and risk.
Jason [00:12:41]:
Yeah. Another thing to kind of think about is, all right, what was the ph of the media before I even started growing in it? And I think a few episodes back, we hit on a lot of initial soak up procedures that are really important to try and get that ph to be a more stabilized area. Fortunately, things like coco are a little bit buffered. And then unfortunately, if they already have a ph that's way off, that buffering is going to resist a change to the ph. And so it might take a little bit longer. You might even be somewhat into the run before you see that ph stabilized in the ranges you want. Yeah.
Seth [00:13:17]:
And if you're dealing with a media where that's a persistent problem long term, you might start to consider some of the economic impacts of having to rinse your media before you charge it quite a lot with nutrient solution. Because Ro is not necessarily going just putting in straight. Ro is not really going to change that ph in the root zone. We've got to reset that with some sort of ion. Ideally the ions we want for plant health.
Kaisha [00:13:43]:
Oh, my God. Outstanding, you guys. Great overview. Just, I want to ask this follow up that was posted on YouTube just to kind of close out this conversation. All questions are welcome, but we got the post here. Hey, guys, I have more of the opposite problem with ph feeding. Ph 5.8 to 5.9. EC feeding at two.
Kaisha [00:14:01]:
My drybacks are just cutting it at ten to 15%. My runoff ph is 6.5 to 6.6. How do I go about getting ph in range? What would you advise for this person?
Jason [00:14:12]:
So, on this one, I think this one's easier to answer because it sounds like a feed of two. EC is probably going to be the main contributor in this one. That's your plants are running out of nutrition. As Seth was mentioning, a lot of what those plants are eating up are going to be the ions that help stay in that range. And so when your EC is that low, you've probably just seen an imbalance in the nutrients. Yeah.
Seth [00:14:42]:
And that's something important to remember. When your input EC is low, it's highly likely that your root zone EC is going to be fairly low because you're not loading it up enough to really overcome the needs of the plant and stack on EC above that. So when we're at a low EC state, if we equate 3.0 ec to 1500 ppm and the plant's taking out, and this isn't anything precise, but it's a good visualization that I like to use. And that's if I have 1500 ppm of salt in the media and the plant's pulling out. On average, we're seeing about a 500 ppm difference in between the time that we load the block up and then the end of the day when we irrigate again, 500 ppm and 1500 ppm load is a pretty big shift. And that's going to have a big impact on your ph. And when we see ph going up rather than down, number one, we're seeing an imbalance between what's available to the plant, what it's pulling out. So that's something to look at.
Seth [00:15:36]:
Another one is to start to go look at your environment and make sure you're having consistent VPD day and night. So we're actually getting proper uptake of nutrients overnight. What is your light load like? Do you have a really poorly lit room? That can definitely be part of the equation here where we're putting all that in and the plant is not really utilizing as much of that as we expect. So we're pushing that ph up in range. There's a few different things to look at and like everything. Check all your boxes and make sure everything is in line for every parameter that you want to achieve here. If we're chasing pH, but we've got pretty bad environmental problems, it's going to be hard to really correct that ph in a meaningful way until we get that environment back in line. And then the important part of that to consider too is if our ph is low and then we've got some environmental issues, we've got to fix that environmental issue at the end of the day to get the yield and quality we want.
Seth [00:16:29]:
So it's kind of back to the old, there's no easy band aid with this. And everything is interconnected to an extent.
Jason [00:16:37]:
Yeah. One of the, I think, misconceptions that hopefully by following some of the traditional ag and some of the scientific parameters that we're seeing these days, is we'd rather probably just be overfeeding slightly with these plants than underfeeding them. Right. When we consider all of the cost factors that are going into growing cannabis, we would rather just be wasting just a tad bit of money on probably nutrients than losing money based on shortcutting the nutrients. When we think about all the inputs that are cost inputs to grow cannabis, nutrients is usually not one of the top three.
Seth [00:17:15]:
Yeah, a good thing too, to really keep in mind. Looking at big egg models is like, although across the country we've seen cannabis fall to commodity prices everywhere, the commodity price for cannabis is still incredibly high compared to other forms of biomass that people grow to sell for food. So it's a little bit of a paradigm shift where in traditional agronomy we are looking at, hey, what's the absolute minimum we can use to get an acceptable harvest? And then saying, like, okay, as long as we hit this mark, we're good economically, right. Well, with cannabis, we have the opportunity to push it past that point and actually reap a pretty big benefit out of it. So it's worth it to run on the excessive side compared to the deficient side. And also, if your plant, and obviously there's some genetic differences in here, but most plants, if we're taking care of it properly and letting it go through its after 1212 flip determinate life cycle, we can guide that in. And basically, if our nutrient composition is correct going towards the end, we are going to waste a lot of that. As the plant starts to enter senescence, it stops feeding.
Seth [00:18:17]:
A lot of those nutrients are just flowing right by it out the bottom of the pot, and we're just maintaining ph and ec. But that's an example of where, if we go too far one way, a two week flush sounds great. If you don't use nutrients for two weeks, that's a lot of money savings on your crop. But we know now that that's not actually beneficial here. So even though we don't have perfect use on the plants parts of the nutrient, it's still worth it to have it in there.
Kaisha [00:18:48]:
Awesome, you guys. Ph, in a nutshell, just blinding everybody with science. Thank you guys for that. We're going to keep it moving. Our gromy cypher is on the line. He had a question about cure room and humidity. Cypher, you want to unmute yourself and speak your mind?
Guest [00:19:03]:
Yes. So I do have a climate controlled curing room, HVAC, cooling dehumidification for the first seven to 1012 days, my parameters stay within where I want about 60, 60 however, towards the trailing end, it starts to drop in humidity. I do have an ultrasonic humidifier in there, but it just seems wrong to me to be dumping water vapor into my curing space. Do you guys have any recommendations? Is there any standard procedures, potentially a better humidifier or anything you guys could let me know that might ease my tensions in dumping water vapor into my curing room?
Jason [00:19:53]:
Sure. So when you think about the moisture release curves from cannabis in the room, obviously we're going to be, first few days, we're dumping a lot of humidity from the plant mass into the room. Right. We're looking at a plant mass by water weights, like almost 90% water in cannabis. And so right off the bat, obviously, the cannabis plant is relieving a lot of its water content right into the room. And as we start to get lower and lower and lower in water content, the release is actually going to be slower and slower and slower. The total amount of water in the room has decreased significantly. And so I think that's what you're seeing there at day seven, day ten.
Jason [00:20:32]:
I guess the question from my end would be, what water activities, what moisture contents are you seeing in the bud itself at those seven to ten days? And or can you possibly just start to cure that product in totes or in bins at that point? Okay.
Seth [00:20:52]:
And another thing to look at, dude, is what kind of dehumidification equipment do you have in there? Does it have the ability to phase out so you can the drying process? You start with barely being able to keep up, typically. Then, if you've got enough capacity and you have too big a units, you can't slow down that dehumidification later on and slow down that drying process. Sure. Getting some kind of moisture analysis is probably your best bet, because we've seen, especially strain dependent in the same facility grow out in the same way, fairly different drying times on different strains, just due to bud size, density, potency could even affect how quickly that water comes out of there. So getting a way to put a number on it and then really dial it in per strain, because a great example is in one room, we might see some strains come down at day seven, they've hit the desired water activity below zero point 65. Some we might be pulling down at more like ten or eleven. And then another part of it too, is how much volume the room has. That's one factor I've definitely seen where, hey, we've got a big amount of biomass, we're moving into this room that's got a really tall ceiling and that's great at first because we've got a lot of expansion room to breathe, but down the line, it might become very difficult to control that bigger environment.
Seth [00:22:06]:
That's why when you're looking at, like, let's say, curing room design, you only want it to be so big because it costs a lot of money to condition that air and keep it where you want it. The smaller a container you have, the easier it is to control that. But that does come with the caveat of having enough equipment to pull a lot of moisture out of that small space.
Guest [00:22:25]:
I see. So there really is no advantage to dumping more water vapor into the room to keep it at that 60% relative humidity. It's more based on what the flower itself is doing.
Seth [00:22:41]:
Yeah, there totally is an advantage if that's what you've got to do to start to try to maintain that environment. Right. Like, you want to keep it at that 60 and 60 as much as possible. And that might be the. Unless you have a way to really turn down your dehumidifier or somehow stop your ac in the room from pulling extra moisture out, that sometimes the only solution is to put it back in.
Guest [00:23:03]:
And that's kind of what happens.
Kaisha [00:23:04]:
Right.
Guest [00:23:05]:
I get to a point where, well, I will stop with my dehumidification because it does not need dehumidification because it's going so low. But I still do need to keep that 60 degrees. So that is pulling out, again, some humidity. So I put an ultrasonic in there, and it's ro water in the ultrasonic. But would I be doing damage by putting that water vapor back into the room to try to stretch out? Because, I mean, this is happening, like I said, day seven, 8910, where we're trying to stretch it out to more like a 14 day curing time or whatever.
Jason [00:23:41]:
So as long as that water is fully atomized, it shouldn't cause any issues. So really what we're thinking here is, obviously, if we're at 60, 60 in a room at 60% humidity, we could dry that cannabis indefinitely. And it's only going to homogenize at 0.6 water activity. Right. And so that's kind of one of those things where it's like, we know we're pretty safe to not be quite as worried about over drying. If those are the room parameters that bud when we talk about water activity, 0.6 is a pretty reasonable range to try and target. And so it's going to homogenize 0.6 water activity in a 60% humidity room. There's going to be no moisture going into that product.
Jason [00:24:25]:
No moisture going out of that product. Yeah.
Seth [00:24:27]:
And as far as the humidifier goes, using an ultrasonic or some kind of a fogger is going to be a lot better than having any kind of a spray system in there that would risk getting. The big thing there, right, is just don't get water on your dried buds, don't let them get wet and start to form some mold. One thing I've done in the past is just shove that ultrasonic in a corner and then kind of manipulate it with fans so I don't have that vapor stream going straight at the plants. I'll put the fans so that it's pushing it up or at an angle with the ultrasonic.
Guest [00:24:57]:
Matter of fact, that's kind of how we have it, right? We have it so we're not dumping actual vapor onto where our plants are hanging. But like I said, it just seems so weird to me to be adding humidity to a dry room. So that's why I wanted to get your opinion. So I appreciate that you guys have explained a lot and helped ease my mind a little bit. So I appreciate you guys.
Jason [00:25:19]:
Thanks, man.
Seth [00:25:20]:
Yeah, no problem. I don't know. Cigar stores do the same thing. They have a humidor to keep that right where it's at. And that's just a humidifier in a wooden box.
Guest [00:25:33]:
Right. And I was thinking maybe there was maybe a different type of humidifier that would be better than an ultrasonic that maybe you guys could tell me about. Maybe I was missing out on something, but I think you guys have explained it well.
Seth [00:25:47]:
Yeah, there's products out there. Like Fogco is a popular one that's in use in a lot of grow rooms, but you don't really have to get too elaborate with it as long as you're getting enough to keep up with needs.
Jason [00:25:58]:
Cool.
Guest [00:25:59]:
Awesome. Thank you, gentlemen. Appreciate you.
Kaisha [00:26:02]:
Appreciate you, cypher. Thank you. Keep us posted. All right?
Guest [00:26:05]:
For sure.
Kaisha [00:26:07]:
Excellent. All right, we got a couple live questions here. Our good friend iron armor posted on YouTube. I'm doing a small, perpetual harvest in a tent, planning on putting in a plant every 21 days. What is responsible VPD to keep the tent at? Since I will have three plants at.
Jason [00:26:27]:
Three different stages, I'd shoot for 1.2. Yes.
Seth [00:26:33]:
That's probably your happiest medium, where you're not going to dry out your young, plant too much, and you're not going to make it too humid for your plants.
Jason [00:26:41]:
Finishing.
Kaisha [00:26:45]:
Word, iron armor. Good luck.
Jason [00:26:48]:
All right.
Kaisha [00:26:48]:
And keep it moving. Here we got this question over on Instagram from Q. They write flora flex running in at three to 3.25.9 ph. I'm running a greenhouse so my co2 levels and temps flex hit 5.2 ph. The other day on my runoff I dropped my nutrients just a little bit and up my volume. Should I go up in EC if most of my strains are looking amazing? And then they continued. I only have about ten plants with some discoloration but my ph is still low on a few different sections. Strains.
Kaisha [00:27:23]:
What do you all think?
Jason [00:27:26]:
I missed some of those first numbers.
Seth [00:27:28]:
But usually I would up your feed EC and up your volume. Also we need to get more ionic replacement going on in there to reset that balance. And just remember, we always try to go traditional knowledge is go back to try to flush it out. Straight water is going to fix the problem. Straight water can't affect that ph very much. When you just dilute something at a certain ph that doesn't change the ph, you'll have a lower concentration of ions. But that ratio is not going to change if we're just adding water to the equation and trying to flush some of it out. So although it's not intuitive, raising your feed DC is probably the correct move here.
Seth [00:28:07]:
And then just make sure you're pushing enough runoff and monitor it. If you're at five two and it doesn't go right back up to five six, that's okay. If it goes up a little bit over time, that's what we want to see. And hey, if it stays between five two and five four for the rest of the run and your plant health is looking okay, I probably wouldn't obsess too much. It's usually when we see that trend continue to go down that it's really worrying because it's like, okay, we know this is heading somewhere that's going to end up with us having a completely deficient plant, where do we need to take the action to prevent that from happening?
Kaisha [00:28:43]:
Awesome, you guys. Thank you. Q. Good luck. All right, we got this question in on Instagram. Durban Hayes 420 is looking for some advice. What are the recommended time and amount of runoff throughout the plant's like, let me start again. What are the recommended time and amount of runoff throughout the plant's life cycle in one gallon coco core? What would you advise for them?
Jason [00:29:08]:
A lot of it's just going to kind of depend on what you're seeing. As far as ritzone ECs, that's usually what I use to dictate how much runoff that I'm shooting for as I'm doing generative stacking, I'll typically only have enough runoff in order to get pH measurements from my slept straight there. And considering you're in a one gallon coco, my guess is you're going to have quite a few irrigations going on. And so when we look at the opportunity there to stabilize our EC or let it rise, we have even more opportunities because we're irrigating more times. Right. And even then, if we have significant runoff, any of those times, we might be wasting some nutrients. We might be losing an opportunity to stack EC. That being said, during our vegetative bulking ranges, typically I will get enough runoff in order to bring my EC down into check.
Jason [00:30:01]:
And again, as I said, with that smaller substrate and the number of p two irrigations that you're having in vegetative bulking, you may not even need to target a significant amount of runoff. And you may just actually initially get that runoff for the first few days and then decrease irrigations. The whole goal of runoff is just to alter the substrate parameters slightly in order to achieve your desired parameters. Right. And so Runoff isn't doing anything for the plant necessarily. It's just doing things to manipulate the substrate.
Seth [00:30:38]:
Yeah, we're just trying to refresh that nutrient composition there and keep the ph in check. And usually, I mean, five to ten, sometimes 15% of total irrigation volume is runoff is pretty adequate to maintain that. And one important thing too, ph seems to be the theme here. But throughout those first three to four weeks when your plant really is growing, pH is very critical. So although we want to see salt stacking up in the root zone, for instance, still want to keep that ph in check, which means if the plant's feeding a lot, we really need to up that feed Ec to keep up with the plant's needs and actually go above that a little bit to stack while also pushing that runoff to keep that ph in range as we're stacking those nutrients up.
Kaisha [00:31:24]:
All right, thank you guys. Durban Hayes 420. Good luck. Make me think of Durban poison, one of my favorites. Okay, moving on. Tom dropped this question on YouTube. They want to know towards the end of the run, when you're lowering the room temperature, should you drop both the daytime and nighttime temperatures or just nighttime temperatures? And what would the target temps do you have for Tom?
Jason [00:31:49]:
Yeah, so this is going to be a little bit strain dependent on how long you're dropping them for as well. Typically, I don't try to drop the room any lower than about 75 for my daytime temps. And then I'll do a max of a ten deg differential night to daytime. If you go any lower than that and you're still having a significant nighttime daytime temp, you're probably just losing out on some yield because we're getting below some of the optimal rates of plant growth when we think about it. All right, what are our goals of dropping temperatures? Typically, we talk about anticyanin production, so that's responsible for the purple coloring that we see in there. And a lot of times we can get enough anticyanin production just by dropping nighttime temps, keeping our daytime temps close to where we might have been at, and optimize the yield there. Sometimes a little bit cooler temperatures, we can actually get a little bit harder buds as well, a little bit more dense. So it's going to kind of depend on how does that strain respond to a change in those daytime temps.
Seth [00:32:55]:
Yeah, there's obviously some pretty big strain differences. And take into account what your lighting is and when you're trying to dial these room parameters, one of your best friends is going to be a little laser thermometer, because we're always focusing on, what is that, the room temp. That's all great, but what is your actual plant temp? What does that leaf surface temp look like? So if I'm trying to get that overnight differential, especially in, let's say, an HPS room, I definitely do want to lower that ambient daytime temp down to, let's say, 75, because my average plant temp is still going to be in that 78 to 80 range. Whereas if you have leds, it's really important to go out there and get that temp, because 75 degrees in the room with an HPS for the plants might be a lot more like running it at 78 to 80 ambient temp in the room under your leds. So really make sure you're targeting that actual leaf surface temp. And then from there, we want to see an actual ten to even up to a 15 degree differential in the actual plant surface temperature. So for HPS growers, traditionally that meant daytime temps for the last two or three weeks, running down at 75 as an average in the daytime, down to 65 at night. With led, especially if you have really good airflow, we might be looking at more like 80 to 82 in the daytime, all the way down to 65 at night.
Seth [00:34:13]:
But as Jason said, there's a balance between slowing down plant metabolism and promoting certain characteristics, like hardening up the nugs. And then there's obviously, like an upper limit to how hot you want to go before you start hitting things like foxtailing, lower potency, bigger, stretched out individual cells on the buds. So short, sweet answer is, yes, we do want to drop that temperature. And part of it's because, hey, this plant evolved to ripen up generally in the fall. Anywhere it was growing naturally, it's ripening up as it's getting colder. That's a signal we're sending to the plant that, hey, we're going into fall time to continue to ripen up and focus on reproductive growth more and more, rather than any more vegetative growth.
Jason [00:34:54]:
Yeah. And I think one of the important things that's always hard for me to incorporate into these conversations as well is when we're talking about a specific number, we're not always representing. All right, that's usually the set point that we're trying to manipulate. It's not representing the space of the room or the plant population. Correct. And this is really where taking more samples of leaf temp and or considering where is my thermometer or my humidity sensor in the room? And is it representing it specifically? Right. So when we look at any population of those plants or any analysis of the volume in that room, it's going to follow a t curve, and we need to analyze. All right, does the sensor we're reading, does our set point represent the exact middle of this t curve? And how wide is the standard of deviation for this? All right, so let's say we've got a big greenhouse and we're at ten degree deviation across the room.
Jason [00:35:53]:
Well, if we're pushing to a set point at, say, 65 degrees, we might be starting to push the boundaries in some of those cooler areas. So do keep that in mind when you're making these decisions on how far do I want to push these set points? Do I have the tight enough deviants in the room or variation in the room? Is it tight enough to really start pushing the envelope on how much I can induce these favorable characteristics?
Seth [00:36:20]:
Yeah, and that's a great point bringing up, like, the greenhouse, because that's not the only situation where we've got a gradient in temperature and humidity in a room based on how the airflow works inside of that room. A great example for anyone who lives in a northern climate if you're in a greenhouse is this time of year, it was 34 degrees out, I believe, when I parked my truck. And. Okay, can I get that nighttime temp lower? Absolutely. Can I lower it in the day? For sure. But what does that mean in my environment? And here on the palouse, that means pulling in 34 degree air right now to the front of the room. So suddenly, if I try to make too drastic of a change now, I've got a really big gradient between the front and the back of my room to the point where if I've got, let's say, a 40 foot long bench, the front third of that, it's going to have a significantly darker color because it's experiencing 34 degree air coming into the room. And by the time it's hit the back of the bench, we've actually had some homogenization because of the different fans in the greenhouse, and that not as dramatic in most indoor settings.
Seth [00:37:25]:
But you really want to think about how homogeneous your room is and what those effects have. Because if I go like, let's say, set a room down to 65, and that means one corner of the room goes to 58, right next to the ac register, I might be having some condensation issues. That, number one, not great to have any kind of condensation in the room dripping on your buds. That's usually how we see aspergillus pop up in its most severe forms. And a lot of times that's going to happen at night. So you might not be aware that it's happening until you see the damage that's going to come from having your buds get rained on.
Jason [00:38:02]:
You just remind me of an anecdote and how much fun some of this stuff can be when you get to face a challenge like that. Right now, if you pop that wet wall open to try and induce a little bit of temperature drop there, like you said, 34 degree air coming in, and I was like, all right, let's program the gable vent to open. Anytime that we've got a bigger temperature difference, don't use the wet wall, use the gable vent. And then even on a day like today where we're very overcast, it might actually be beneficial to close up the.
Seth [00:38:31]:
Blackout a little bit.
Jason [00:38:31]:
And then when we're using that gable vent, we might even have a more stabilized environment across the room. So whatever situation you're in, try to spend the time in there to really get the feel of it. Take measurements so that you have an agnostic answer of what's going on in there on top of your feel. See if those agree with each other, and then start to get creative with how you can make the best of the space.
Seth [00:38:53]:
Yeah, absolutely. I love the blackout example, I drove by a greenhouse on the way here that had their blackouts pulled and light solder, their blackouts pulled, mostly a little bit of heat regulation, but that's because right now it's really hard to heat that greenhouse in an efficient way where you don't get condensation on the ceiling. Well, there's really no greenhouse panel out there that's nearly as well insulated as, like, a regular wall or insulated roof. So, hey, in that situation, that does end up being the solution. Does it seem kind of odd to pull your blackouts because you want to use the sun? Sure. But it's way better to pull your blackouts and not have your crop get rained on a few times a day than it is to deal with that.
Kaisha [00:39:36]:
I love that troubleshooting reminder. This is a resourceful community we have here, so love that. All right, we're going to change gears a little bit. This question came in a few weeks ago. We weren't able to get to it. We get so many questions. Love it. Thank you all for that.
Kaisha [00:39:51]:
But chronic Sosa recently got powdery mildew in week six of flower. They want to know, do you think I can still use it to make bubble hash? It's not really that bad. It's just on some leaves. And then also, after dealing with powdery mildew indoors, what would you recommend to kill all these mold spores for home growers? Let's talk about it.
Jason [00:40:13]:
If it's a home grower thing, like, you can smoke whatever you want to smoke. So there is that. Would I make bubble hash out of it? I guess it depends how much products I have and how much I need and what I need to do with it. A distillation would probably be a safer bet for anything that is contaminated a little bit like that. That's kind of some of the fun of home growing, too. It's like, which buddy is going to get the rough sack here today. You just got to watch out. Maybe he's also one of your best friends to make sure that you're not getting whipped up on at the end of the day.
Seth [00:40:57]:
And typically, too. It just depends on how bad it is, right? Did you just see it on those bigger fan leaves? Was it setting in on the actual bud leaves themselves? A lot of that's definitely going to be up to your judgment. It's not generally as bad to encounter powdery mildew as it is, let's say, an aspergillus related infection or betritis. That being said, I didn't see how much snow is all over your plants as far as cleaning goes, though. Hey, don't be scared of bleach. Clean the absolute shit out of your entire grow area. Start to be really careful about what clothes you wear and don't wear in. Just because you're not at a big scale professional facility doesn't mean like, hey, you shouldn't have some biosecurity rules about what shoes you decide to wear in, whether or not you have inside and outside clothes.
Seth [00:41:49]:
A lot of the facilities out there have gone to, if not providing scrubs for their employees, at least saying, hey, we've got locker rooms. And you do a clothes swap, very least shoe swap, but ideally a closed swap in between walking in off the street and going into the grow room. And then don't discount when you're trying to get rid of powdery mildew or mold in an environment. It, to me, can be kind of similar to trying to get rid of thrips. So start looking for all the nooks and crannies and places that you can have biomass build up. And don't discount the smallest amounts of organic matter and dust that can actually hold some of these spores and keep them around. The thing with powdery mildew is it typically comes in. It's not the easiest thing to control.
Seth [00:42:30]:
If you can keep your humidity in check, it usually doesn't get too bad. But once it's in your system, you want to really be careful and clean it out. And sometimes, especially if we're talking about a garage or basement or whatever smaller facility, your dry room might not be getting the attention it needs. It could be hosted in there, and then you're spreading it around the rest of the facility. So really clean hard and start looking at, like I said, really nooks and crannies is where I see it pop up a lot. The places that are hardest to clean usually get cleaned the least, and that's where we see things being fostered and held.
Jason [00:43:08]:
Yeah. One of the things that I've found growing at home is the more attention to detail I put in before I start growing it, the more fun it is to grow in it. Anything that is going to be more difficult to keep clean, it's just not as much fun. Right. And so a lot of times I'm so excited to get these seeds popping and start rocking and rolling that I'll cut some corners. And it seems like when I do that, I end up spending two or three times the amount of energy later trying to fix stuff up after I've got rolling. So give yourself a little bit of extra patience there. Maybe an extra few dollars just to get your set up as nice as you can afford and spend on it, both energy and time wise.
Seth [00:43:50]:
Yeah, and don't discount the elbow grease. They're still a huge part of the grower's hands. There's still work sometimes in trying to eliminate some of these problems, and that can be compounded when you've, uh. I'll just use my house as an example. I have a dog and my backyard is full of powdery mildew. I live in the Pacific Northwest and it rains here every day. Right. You know, what can I do? Well, I don't let my dog in the grow room, for starters.
Seth [00:44:18]:
And then I just try not to go in there as much as possible. Additional steps are adding filtration to your incoming air so you can really isolate that grow room. Possibly going to a fully sealed situation if you want to add co2 supplementation to your situation if you don't already have it. But really isolating that and making sure all of your incoming air is clean and that the room itself is super clean. And sometimes that goes back to design. If you've got a converted office or bedroom, let's say, and you went in and painted all the walls white and everything, sometimes you can harbor mold and things like that in sheet rock. That might be a design element that you decide to change for something like trust core or real advice from lessons hard learned. Don't staple panda film up in your grow room.
Seth [00:45:08]:
That's just going to create a place behind that panda film to grow things on your sheet rock. So, like we always say, the holistic approach, really get in there and hopefully it's not too dirty in there, but be prepared to get dirty and possibly modify some things that just aren't going to work in that situation for biosecurity.
Jason [00:45:26]:
And probably the last one I think we talk about quite a bit, but we didn't mention here, is just environmental control. Don't let things get to run away on you with the humidity.
Seth [00:45:36]:
Yeah, really. If you don't have something to monitor your environment. Twenty four seven. I would say that's one of the best investments you can make. Even if you've got an eight year old blurple led that's 600 watts, and you don't like how that's performing if you have, like, a high humidity condition at night or at lights off that you're blind to, nothing you do is going to actually fix that problem unless you fix that environment.
Kaisha [00:46:04]:
Fantastic advice, you guys, and just want to add our knowledge base. We've got some articles specifically about powdery mildew, and they're pretty great. I know because I wrote them, so check them out. Thank you guys for that. All right, we're going to move on to the next question that came here on YouTube from Ian. Ian writes, I am seeing the substrate EC go down along with the water content when it should be an inverse relationship. It is day 14 of flower feeding, 3.5 ec runoff. Ph is 5.7.
Kaisha [00:46:34]:
What would cause this? We have 600 plants and one gallon coco. We're using aroya with 20 tarot, twelve sensors. Oh, appreciate you. Good looking out. All right, what do you guys think?
Jason [00:46:44]:
Hungry plants is usually what we're seeing in there and we think about, all right, so we're in a one gallon coco. Our nutrient level is a concentration, right? So the smaller amount of water we have in there, actually the smaller amount of total nutrients that the plant has access to. So that's usually what I see when the AC is dropping with water content, is that a plant's eating it up as fast or even slightly faster than we're replenishing the substrate. Yeah.
Seth [00:47:13]:
Especially if you're vegging in that one gallon coco pot. There's a good chance you hydrated that, charged it up at a 3.0, drop a clone in, and then we're really not putting a whole lot of water on that plant for, like, let's say that first five to seven, even eight days, throwing a clone into a one gallon, we're putting on some small shots to encourage root growth, but in order to get that vault or that mass of salt into there, we have to deliver enough nutrient solution with our concentration to actually get that amount in. And a lot of times what we see is even feeding at a 3.0 and veg, if we're going in and say we got a 14 day veg and we're not feeding an appreciable volume until day seven or eight. At that point, once the plant takes off, if we've only ever reached about a 3.0, because that's all we've done, is continue to put in 3.0 as the plant's eating and replace it, suddenly we'll go into flip. And once in flower, we go to 1212, that plant takes off, that stretch starts going, and its needs for EC increase dramatically. And if you start, general value is anything below a 4.0 going into flip in most of today's modern high intensity environments is going to be not necessarily deficient, but it's going to be difficult to stack EC up on top of that, because that plan is eating through almost everything you're putting in every single day when you're at that low EC state. So typically when we see that EC line be parallel to the water line, the water content line, that usually corresponds with a pretty low EC situation. If I had to guess, your in root zone EC is probably between a two and a four.
Seth [00:48:46]:
And basically it goes up when you add water and salt in, then that plant is taking out most of what you're adding in throughout the remaining 23, 24 hours. So goals for next time get that EC up in veg. And one little trick that I've definitely employed is like, hey, I've been feeding a 3.0 in veg. Most of my plants are somewhere between 2.1 and a 3.2. Let's say I'll go in and feed out a 4.0 for a day or two before transplanting, just to try to stack a little bit more up in that root zone before flipping over into flower.
Kaisha [00:49:23]:
Awesome, Ian. Good luck. Keep us posted. All right, Nana dropped this question on YouTube related to EC as well. They're wondering why running straight fertilizer salts at a lower EC is satisfactory. Is there something like a filler or anti caking agent in Athena that causes such a high Ec? What do you guys think?
Jason [00:49:46]:
I mean, different nutrient blends are just going to result in different ecs. We see it across the board as far as, is there anti caking agent in these? Yes. Quite a few of the mainstream manufacturers do put an anti caking agent in their salts, and this comes from direct feedback that we see from the clients where they're like, hey, I had a rock solid block of nutrients and it's damn hard to mix because I got to beat it up with a hammer first. And most nutrient suppliers that we see these days, when they get responses of bags that have gone solid on them, they just replace that stuff. That's why they do caking agents is, one, to keep the clients happy, and then two, to keep return product down. Yes.
Seth [00:50:34]:
Also, it's a recognition that, hey, most of our bigger growers out there, number one, we're going to mixing salts. Number two, automation is entering the game. So we're usually mixing a lot of these salts from a concentrate solution. So it's in the fertilizer company's best interest to ship you salts that you can mix up in an extremely high concentration for injection. So basically, if I'm trying to put close to a pound of fertilizer in a gallon of water, when I'm making that concentrate, that really needs to dissolve, if I start to have fallout in that concentrate mix, then that's ruining my injection ratio and making it very difficult to achieve my target ecs. So, like Jason said, yes, they have all that and be happy about it. I've definitely used stuff back in the day that did not have any appreciable characteristics for being adaptable to different situations. There's some products I've used in the past that I've basically had to use water ph down to, like, 5.5 and at about 90 degrees to dissolve it in a solution and then dump it into my greater reservoir.
Seth [00:51:40]:
And you do what you got to do. But that's not exactly, like, a desirable trait for a product on commercial level.
Jason [00:51:47]:
Right.
Kaisha [00:51:51]:
On, you guys. Thank you. Okay. Danny dropped this question. He's looking for you individual specific experience. Based on your experience, what causes Hermes the most?
Seth [00:52:07]:
The fact that, although we describe it as diaceous, most plants have the ability to express hermaphroditically. So genetics plus stress, genetic potential, times your environmental potential, always gives you your outcome, whether it's your intended outcome or otherwise.
Jason [00:52:26]:
Hopefully the intended one.
Seth [00:52:27]:
Yeah, so, I mean, that's a thing we run into a lot, actually. And it's something that, in the commercial world, it's really frustrating for a lot of people who are. A lot of growers who are running like, what, in their eyes, is a Ferrari of a facility, right? Like, hey, I can do anything I want in here. And, like, yeah, but this strain, herms, every single time you grow it, and most other strains you grow don't. So is it your skill as a cultivator? Maybe you could grow this in an environment where it doesn't. You know, I personally have seen genetics that, like, let's say, extremely high VPD. So, okay, we grow a desert plant that's just beat up. It has small buds, and we're looking at half the yield we'd normally get compared to any other strain we grow.
Seth [00:53:11]:
And at that point, it's like, hey, just because we haven't put the genetic research into figuring out why this plant is doing that, it probably still is, outside of any kind of economic viability, to try to grow it in a way where it doesn't harm. And we've seen at this point, with such a. Some people are pretty good at keeping track of their breeding projects and lineages, but there is no overarching system that lets us verify anyone's breeding projects. And sometimes that's what we see. Some strange things happen. Just switching some plants light spectrum from HPS over to a more white led spectrum seems to push out herms in these plants. Now, there's a couple of different things to look for when we're talking about herms, too. Are they more stress related? Is it happening in week six, seven, eight, after we've got full on bud set, and we're just seeing a lot of stress in the plant at that point.
Seth [00:54:07]:
Usually that corresponds with other signs of stress on the plant. We've got fading leaves, some leaf tip death, and then the other side of it is, are we seeing actual pollen sacs drop anywhere from day ten to 21 before we even have real bud set? And that's going to result in those buried, fully mature seeds. If I'm seeing those pollen sacks drop immediately, pulling that out of production, because there's a good chance that I am absolutely not going to be able to overcome that in an economic way in my facility. And that's a big risk to all the other plants that I have in that room. And when we're talking about stress herms, that usually is just a stamen popping out of a developed nug, a plant that is truly genetically hermaphrodite. That's when we're seeing those fully developed pollen sacs that actually produce an appreciable amount of pollen.
Kaisha [00:55:02]:
All right, got to check for that strain viability. Always. Thank you for that, guys. All right, we got this question in from Instagram. Somebody's looking for your recommendations. What size pump would you recommend for a twelve light setup? 16 plants each light two drippers per plant. They're wondering if you would go with a three gps net of film drippers or something else.
Jason [00:55:24]:
What do you think? 0.3 gallons per hour, net of him? Drippers are kind of the standard in the industry. There's a few newcomers on the street as far as those drippers go, that I personally like as well. So I wouldn't necessarily just be locked in with those, but usually the lower flow drip rates. 0.3 is one of our most favorites. Two drippers per pot is a great way to go just in case you start to see some clogging on one of them or just basically a redundancy. Anytime we've got redundancy in production, and it might cost us a little, but it's never going to hurt us in the long run. Yeah.
Seth [00:56:00]:
0.3 to 0.5 gallons, pretty standard. One thing that is terrible and awesome about irrigation technology is if you do this for a few years, you're going to have a chance to play around with different types of drippers if you want to, because they all break eventually. So, yeah, that 0.3 to 0.5 gallon per hour, as far as a pump goes, you don't need anything too crazy. Just put your zones out and make sure you've got enough flow. We're not putting on. If you think about any of these irrigations we're talking about, 600 ML would be a gigantic irrigation. That's about a whole day's worth of water for a lot of these plants. Usually we're in that like one to 300 milliliter for a big shot.
Seth [00:56:39]:
If you project that across your entire irrigation zone, that's not a whole lot of flow. The biggest thing we're looking for is getting a lot of pumps at the three quarter one up to 2 hp. Just enough to give you proper line pressure.
Jason [00:56:54]:
Yeah, that's the house I was going to say. I think net of him specs there. Most of drippers at between twelve and 15 psi as far as the opening pressure. So really what we want to do is make sure that we're at probably 20 psi throughout the whole line. And ideally, when you are running that line, try to do it in a loop so you don't have any dead ends on there where you're losing pressure as we're losing water going down the line. That's just going to help make sure that the uniformity across the room in irrigation helps us create uniformity in our crop as well.
Seth [00:57:25]:
Yeah, and don't cheap out like me. Buy the elbows.
Jason [00:57:28]:
They're worth kink. You don't get kink. Exactly.
Seth [00:57:32]:
Just some of those little parts are definitely worth their weight in gold at the end of the day. And keep it simple. Personally, at home, if I'm running my little one lighter set up, I don't even have it zoned out. I have a pump with a timer because I don't want another thing to break in there. And at that scale, you don't need anything too crazy and fancy. And one thing I would definitely caution you against, if you're in this situation is potentially going with a pressure sensing pump, such as a dab pump. Great product, I love them. But if you are in an area where you don't have a drain right next to your pump and you develop a leak, that's one of those points where it's like, hey, that could end up filling up your room over time.
Seth [00:58:14]:
So just watch out for some of those little hiccups that can happen and pretty quickly devalue whatever structure you're working in.
Kaisha [00:58:25]:
Outstanding, you guys, this was such a good show. I'm going to go ahead and end the conversation because I have a very special announcement to make. We want to congratulate Michael Worthington of Flint, Michigan. You won an Aroya go. Thank you so much for entering our contest. And make sure you're tapped in because you never know, we might be doing some more giveaways in the future. So, Michael, congratulations. And we can't wait to see what you grow, man.
Kaisha [00:58:48]:
Good luck next time for everybody else. All right. On that note, Jason and sass, thank you guys so much. What a great conversation today. Thank you, Chris, our producer, for holding it down with me. And thank you all 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 cannabis cultivation platform. If you have any crop steering or cultivation questions you want us to cover, drop them anytime in the Aroya app.
Kaisha [00:59:16]:
Email us at sales at or send us a DM. We're on Instagram, Facebook, and LinkedIn. We want to hear from you. And if you're a fan of the pod, be sure to subscribe to our YouTube channel so you never miss an episode. Thank you all so much, and we'll see you at the next session. Bye.