Cian [00:00:03]:
What'S up Gromies? Welcome to AROYA Office Hours Episode 136 your, free your source for free cannabis cultivation education. I'm your moderator CN our director of Applied technology, Jason and today we have a special guest, Anders Peterson, Director of horticulture at PIPP Horticulture. If you've ever looked up in a grow room and seen wall to wall canopy stack several tiers higher, there's a good chance PIPP was behind it. The they've helped shape how multi tier growing works at scale. Anders has been right in the middle of that evolution. Today we're going to cover Andrew's origin story, the current state of the industry both domestically and internationally, best practices for multi tier growing, what's new in 2025 and some common pitfalls. You might see how to implement data driven solutions for improved yield and whatever else we might wander into talking to today. U.S.

Cian [00:00:54]:
some questions, if you guys have anything you'd like to ask us specifically or if you'd like to ask anything to Anders while we've got him on the show. And let's jump right into it. Anders, you want to introduce yourself and tell everyone a little bit about who you are? Yeah, sure.

Anders Peterson [00:01:08]:
Thanks for having me on the show today. I will admit I am a fan myself. I listened to this for the last couple of years and I've always enjoyed the content. But yeah, I'm Anders Peterson. Um, I've been in the cannabis industry full time since I was 15 years old from the Bay Area, California. Grew up near Berkeley in Oakland and started working indoors at an 8,000 square foot single level. HPs grow after high school every day and trimming for all of the Berkeley hippie growers on the weekends. And I just fell in love with the science and engineering of growing plants indoors without sunlight.

Anders Peterson [00:01:49]:
I ended up going to college for cell and molecular biology. That whole time I was running Prop 215 cannabis companies here in the Bay Area. And ultimately I moved my grow from Berkeley over to Oakland when they started issuing licenses. And at that time too we were making a lot of full melt bubble hash. So that was a huge passion of mine. In fact, one of the reasons I got more and more into cultivation was to grow better trichomes to make better full melt. So that was kind of my passion when I was younger. Ultimately over the years I've worn a lot of hats in the plant touching side of the industry.

Anders Peterson [00:02:27]:
From owner, operator of dispensaries, extraction companies, indoor cultivation. I helped start a testing lab and about three, four years ago I moved to the vendor side of the industry. It was my first ever non plant touching job. And I ended up working for an H VAC startup in Berkeley called Inspire Transpiration Solutions. And it was somewhat of a selfish move for myself. I had been growing for so long and I felt like H Vac and climate control was probably my weakest area of knowledge and, and I wanted to understand more about it. So I immersed myself in that world to become a better grower and understand that technology better. Ultimately that led me to my position at PIT Porticulture.

Anders Peterson [00:03:15]:
And I'm super grateful for it because this is a wonderful company to be a part of. And as you mentioned, we've done a lot of grow rooms over the years, actually about 5,000 grow rooms worldwide over the last eight years. And I have the most fun job in the world. I basically get to travel nonstop to all these facilities, see what works, see what doesn't, and then develop best practices for design and how these rooms are laid out, how irrigation, H Vac, all that integrates into these multi level racking systems, and then take that and develop new products at pip. It's, it's quite a fun journey, man.

Cian [00:03:53]:
That's awesome. I think that's a great introduction to who you are, how you came to be where you are in the industry. And you know, I kind of wanted to jump into a few things on kind of the trends you're seeing internationally. But before I do, Jason, you got any opening questions for Anders to kick us off?

Jason [00:04:14]:
I'm just really excited to have him here on the show. Anders and I've been bullshitting for a number of years and probably someone that I don't meet a lot of people that's been to more facilities than myself over the years of visiting clients. And so it's nice to have someone here that can, can really one us up as far as feet on the ground, inside industry knowledge. And obviously he's got tons of plant education as well, so just, just really honored to have him on the show.

Cian [00:04:47]:
Same here. I was sitting at a table two weeks ago with Anders and Dr. Nadia Saba and Dr. Allison Justice. Right. And I was sitting there thinking the same thing, Jason. Like, wow, the compendium of knowledge and the people in front of me in this table. Just pretty wild to think of how many different facilities these people have all been into.

Cian [00:05:12]:
And it's awesome to have you onto the show this weekenders.

Anders Peterson [00:05:17]:
Thanks, man. It's funny, someone challenged me recently to ask how many facilities I'd been to and I think in the last five years, I've been to close to 400 facilities worldwide. About half of those I have full architectural and engineering plans for. And at every facility, I have like a minimum requirement of data I try to capture so I can track various trends and room sizes, canopy, square footage, lighting type, you name it. I will say I really miss being in the garden every day. I really miss running my own facility. I was shocked how much better of a grower I got when I stepped out of that bubble and started visiting other facilities and talking to other growers. In fact, I can't wait to get back into my own grow and kind of implement a lot of the things I've learned from just traveling something facilities.

Anders Peterson [00:06:11]:
It's important to get it.

Cian [00:06:13]:
Something someone told me when I first started doing a little bit more educating than hands on cultivating was that you, you never learn it better yourself than when you have to teach it to other people. And when you get to do that on site with so many different varieties of facilities and so many different options going into these different build outs.

Anders Peterson [00:06:40]:
I.

Cian [00:06:41]:
Think it really sharpens you and I can definitely speak to that as well. My runs since educating have definitely been much better than runs that I had looking back. And you know, a huge part of that's just learning from such a wide variety of people, seeing such a wide variety of these situations, these different build outs, how they operate, the challenges people face and the wins they have. And I definitely echo what you say, it's one of the best jobs in the world to be able to go around and to help people get better at what they're doing in these facilities. And I mean, from your perspective, planning them out and then seeing these plans executed must be just so much fun. I can't imagine.

Anders Peterson [00:07:24]:
Absolutely, man. It's. Every facility is unique and different, has their challenges, but every single one, I feel like that gets built today is getting a little bit better and we're learning more and more that we are.

Jason [00:07:36]:
Before we jump into the next question, I know you just got back from Berlin. I've got some shared clients down up in Switzerland there. Maybe give us a brief, brief intro on what countries you've been working in.

Anders Peterson [00:07:51]:
Oh, so let's see here primarily, obviously United States and Canada. I've done some work in Switzerland, Germany, Holland, Portugal, Spain, Macedonia, Denmark, Austria, Australia and South Africa.

Jason [00:08:08]:
Very cool, man, Very cool.

Cian [00:08:11]:
I mean, honestly, that leads right into it because I was going to kind of steer us next into, you know, with your international knowledge, some of the international trends, you're seeing differences between Some of the international markets that you work in and the legacy markets in the United States that you've been a part of.

Anders Peterson [00:08:34]:
That, that has been such an interesting journey the last couple of years, maybe the last four years in particular, spending a lot of time overseas talking to the growers out there, even in different countries and regions across Europe. The cultivation mindset, the differences in strategies. Like one of the things that stood out to me immediately talking to growers in Europe is how much they love doing veg in place where they actually don't have veg rooms and they, they run a super high plant count, almost no veg, just enough to get rooted into the substrate and they flip them right away. So that was really. And it's pretty pervasive, you know, across a lot of European facilities. So right away that one was quite interesting to me. There seems to be a spectrum of cultivators overseas that some of them really want to learn from all the resources and information we've learned here in the United States and others want to make these mistakes themselves. You kind of get a broad spectrum of that.

Anders Peterson [00:09:39]:
And then of course, since legalization, these markets are a lot more nascent than we have out here. They're still going through the learning curves of going from, you know, DIY built yourself trap grows to professionally built large scale commercial facilities. So you get a lot of questions around like CO2, life safety, fire code, how to size these different rooms to scale them all efficiently, you know, operational flow. I like to do a lot of like spaghetti diagrams of people flow, plant flow, waste flow through a facility and show them what these floor plans mean to them in operation. But dude, no matter where you are in the world, all growers want to grow fire and they all have a passion for it. So that isn't really much different. I would say the genetic choices are different that they're growing out there. I love how the Dutch growers still run a lot of longer flowering sativas.

Anders Peterson [00:10:36]:
The Hazes are still dominant out there within the skunks. I mean, you get some western genetics for sure, but I would love it if more growers would take things a little bit longer and grow some different varieties other than the candies and the skittles and some of the OGs we see. So I love the variety. I love shopping for smoking weed out there. Actually, one of the countries I missed was Israel. We, we have a grow there too, and they're even growing some really interesting Haze crosses. But yeah, that's kind of my take as of now. And you're Slowly seeing more and more big facilities being put together, not so much in Germany, but particular Portugal.

Anders Peterson [00:11:18]:
Some big grows down there.

Cian [00:11:20]:
I feel like. I've heard the, the diverse genetic palette be a common thread from a lot of my friends that have gone overseas recently. Just that there's, there isn't the dominating, like you said, skittles, runts, OG's kind of market that we have seen for such a long time in the United States. And you know, seeing like you said, some of those hazes things that aren't quote unquote as commercially viable in a lot of situations here in the United States currently, I think it's awesome. I love smoking those myself. And so seeing that there's still, you know, personal preference trends towards those types of things in other markets is kind of close to my heart. Makes me happy.

Anders Peterson [00:12:10]:
Yeah. And I hope they continue growing them. I hope that legalization and the need to be profitable and have a low OPEX doesn't narrow down that genetic diversity in Europe too. Like right now one of the things I'm seeing is a lot of these markets prefer importance overproduction nationally. So while some cannabis is grown in these countries, a lot of people are importing from Canada and South Africa. You know, is it the best quality product? Sometimes, but you lose something in transit and I, my hope is that the consumer starts demanding freshness. You know, I know here in California a lot of states like mass like they shop off tack total active cannabinoids. Right.

Anders Peterson [00:12:56]:
And highest THC sells the fastest in a lot of states. That used to be the way here in California. Now I've seen a trend where consumers are requesting harvest date. You know, they want, they want fresh cannabis. They don't want something that's been sitting on the shelf for a year, you know, 10 months. And I'm hoping that's what happens in Europe too. Not that I'm against importing cannabis from overseas, it's just I would love for these markets to develop their own cultivation infrastructure.

Jason [00:13:28]:
Yeah, it's going to be important for really for the markets to excel as fast as possible up there. They do need to in house it. I think that keeping those legacy strains popular, I sure hope that the consumer can drive that rather than obviously here stateside. It's just the competitive nature has driven a lot of that out of the shelves. Up here in Washington state we do get to see some super silver hazes, some of that older stuff, blue dream on the shelves and things. And I'm really excited to see and hear that California's they're starting to move past the total THC as the main selling point of a bag of flourishes.

Cian [00:14:22]:
Also kind of wanted to ask what you're seeing in terms of facility spec out and build out trends in the international markets. How's the adoption of multi tiered systems, for example, going overseas versus what we've seen a lot of places, especially urbanized places in the United States. Do.

Jason [00:14:46]:
You?

Anders Peterson [00:14:46]:
Yeah, it's a good question. I think as of right now they're a little bit slower to adopt the multi tier cultivation in Europe, especially in flower. And I think what you'll see is very similar trend to what happened here when multi tier came into the market. Right. Because you know, the multi tier as we know it, you know, the pip, the PIPP systems and mobile racking and you guys are familiar with what our products are. They really weren't viable until Fluence dropped that spider. You know, like that was the very first, like widely adopted LED horticultural fixture by growers that I can recall, you know, at a large scale. And it was just very fortuitous that PIPP entered the market at the same time.

Anders Peterson [00:15:31]:
And the two companies shared a lot of shared growth, mutually beneficial growth and that kind of made it viable. In the early days of PIPP entering horticulture, the main rooms we built were veg rooms and that was a product of a lot of facilities being built really quickly on the west coast without best practices for architectural design. They essentially shortchanged themselves on veg. They were bottlenecked there in their nursery and they couldn't supply all their flower rooms. So the only option was to go vertical to increase your veg canopy and be able to close that, you know, end that bottleneck and be able to fill all those flower rooms. And then once they got comfortable in veg, you started seeing more and more flower rooms being built. Two, three, two or three tiers high. I think that's going to be similar in Europe.

Anders Peterson [00:16:23]:
A lot of them have never grown multi tier. A lot of growers there are still on hps. More and more are transitioning to led and I think that they're going to have to get comfortable at a commercial scale before a lot of them truly adopt multi tier. I mean, I'll tell you right now we're building, I don't know, off the top of my head, like we got maybe 10 facilities in the works right now out there that are large scale multi tier, but it's not like, you know, every single one is going that route. There's definitely a learning curve going multi tier. If you're comfortable, single level. And if you compare cannabis vertical farming to non cannabis vertical farming, non cannabis vertical farms are only built in a, in a very specific set of requirements. Geography has a huge impact on that.

Anders Peterson [00:17:18]:
You know, where are you located and market demand, market price. So like if I was to build a massive indoor vertical farm here in California to grow lettuce, that would be kind of ridiculous considering how much a lettuce is grown here outdoors and how fresh we get it and our access to that produce. But if you're talking about building an indoor vertical lettuce farm in New York or Florida, that makes a lot more sense because of the transit time it takes to get produce there and they pay a higher market price and so they're willing to accept that slightly higher price per head of lettuce in New York or Florida than we are here in California. In fact, a lot of non cannabis vertical farms right now are built on island nations, import produce from the mainland like Puerto Rico, Costa Rica, Bermuda, Bahamas. Cannabis has been lucky because of our crop value. I mean, for the longest time we've had the highest crop value in the world. It's allowed us to innovate and make mistakes on design of these facilities and absorb some of those mistakes in our, you know, in our opex because of just the margins. But that's not the same in other crops.

Anders Peterson [00:18:28]:
Now as our margins are shrinking, the decision on where and when to build multi tier and cannabis is becoming more pronounced. So geography, real estate, one of the biggest things, like in Switzerland for example, it's really hard to get a 100,000 square foot warehouse in Switzerland. You know, you're dealing with smaller buildings that most of the time have pretty tall ceilings. And so now you're able to invest in a smaller piece of real estate with lower property taxes and produce the same amount that you are with a building two, three times the size. So a mentor of mine would call that fixed cost absorption. And so essentially you're spending less money on your fixed costs of your property and real estate, but producing a higher quantity in that area and that volume of that cube. So more and more, I mean, you know, if you're building in area with super low cost of real estate, low cost of labor, maybe it still makes sense to go single level, right? Maybe your building has ceiling heights where it just does. You're forcing something that is not natural, going multi tier, like you have a 10 foot ceiling height, it's going to be tough to do it that way.

Anders Peterson [00:19:47]:
So there's situations for both. I'm not a 100% multi tier guy. I think it's a tool in a tool belt and you got to pick the right tool for the job.

Jason [00:19:58]:
How short of tier can you go? I've been in a couple of facilities. I was like, I probably only would have gone with two tiers instead of three in there.

Anders Peterson [00:20:08]:
Man, I've seen people go like 40 inches or less and they struggle for sure. My ideal tier spacing from grow tray to grow light is somewhere between five and a half and six feet. That's kind of my optimal spacing. You know, if you're running a no veg or veg in place and you're having like a, you know, 64 plants per four by eight, like some of these Dutch guys, you know, you can go shorter than that, you know, you can go less than five feet, but you know that you're gonna have to control plant height and manage your veg length to determine that finished plant height.

Cian [00:20:47]:
And to that end, what do you see for common pitfalls and mistakes and miscalculations people make when they do jump from that single to a multi tier system? If they've been comfortable growing like you said, you know, single tier HPS system, and all of a sudden they're in a newly specked out facility running two to three tiers and kind of wondering why it doesn't work the same that their old system did.

Anders Peterson [00:21:18]:
Yeah, there are a couple that come to mind. First of all, if anything, multi tier forces you to understand the characteristics of your cultivars almost at a more microscopic level than single level H or led. You really have to go through the crop registration program and truly understand how these cultivars grow and be very strategic in your plant rotations and even your planting locations. You know, grouping them together in zones that in cultivars that share similar characteristics, that's one thing. Like for example, when we first started, people are like, you can't grow OGs and multi tier or GMOs. Right? You totally can as long as you understand the characteristics of those cultivars and you manage them appropriately. So a lot of growers are scared of plant height and stretch. Ultimately when they get comfortable with it, it's almost like a non issue, you know, that would be one.

Anders Peterson [00:22:19]:
And I mean the biggest kind of low hanging fruit mistake I see with whether it's a retrofit or a new build is the mechanical system. So H vac and airflow. I've seen facilities take a single level HPS room and throw two tiers of of LED flower in there and not retrofit their cooling or dehumidification capacity and wonder why is it my, why are my yields at 40 grams a square foot? Well, you're out of balance. Your room is out of balance. You can't control that much transpiration and light load in that space because you've just doubled or more than doubled the amount of canopy square footage in that space producing water vapor and generating heat from plug loads of. So mechanical systems, whether it's multi tier or single level, out of all the grows I've been to about 90% of them, that's their limiting factor. And you can't also approach a mechanical system design. And for listeners, when I say mechanical system, I mean H Vac and dehumidification primarily.

Anders Peterson [00:23:22]:
Right? You can approach a multi tier room like you do a single level room. So it's a whole new approach to how you would distribute that capacity through supply and return duct work and how that supply and return ductwork work works in conjunction with your in rack airflow systems like the one we have, our BAS 2.0 at PIPP. They have to work synergistically. If you have conflicting airflow patterns where you have a weak link in the chain, where that capacity is directed to the wrong places in the rooms, your climate suffers and it's hard to have a consistent VPD across your canopy. So those would be kind of my two, my two biggest ones.

Jason [00:24:04]:
What's a good way of determining in room consistency? Is this something that. Yeah, we absolutely have to sit down with an engineer and plan out obviously our racking system. Great to talk to you guys about that type of stuff. But as far as external H vac venting areas, load capacities, you know, is that something that we want to measure before we go in the room, you know, during retrofit and after we've get some plants in there or what's the best way to sample a process like that?

Anders Peterson [00:24:38]:
Well, I don't know if this is the right answer to your question, but for example, I get calls from customers who say, hey, I'm having challenge managing my climate. How many more dehus do I need? Or how many more tons of AC do I need? Right before I do anything, I say let's quantify the problem. So, so let's go through and take leaf surface measurements throughout your canopy and get ambient temp and RH measurements throughout your canopy and essentially heat map the room. Same with airflow. Take a hot wire anemometer and go take manual measurements every eight feet or so and understand what velocity of airflow and feet per minute, you're getting across that canopy as well. So quantify the problem first and then come up with a solution that's a retrofit of your mechanical system. Sometimes it's just a change of your duct work, like, let's say your air handlers and de minification were sized appropriately. It's just that capacity is directed in the wrong spot.

Anders Peterson [00:25:36]:
Frankly, this is a big part of my job at pip is coming up with these best practices for duct work. And in rack airflow and sizing. I have honed in on kind of two standard designs. One for a row length of 40ft or less, and then one for a row length of 40ft or greater. Because we in a multi tier design, we're essentially taking a single level design and flipping it on its head, similar to how greenhouses are done, where you're supplying air through a wet wall in one end and you're pulling it across that canopy and you're extracting it from the other end or through, you know, ridge vents. That's oftentimes what works very well for multi tier rooms is supplying about anywhere from 70 to 100% of the CFM of your H Vac system in the front main aisle of your room, which acts kind of like a mixing chamber where it's mixing and blending with the room air and then allowing your in rack airflow fans to capture that dehumidified conditioned air, push it down the length of the row and return on that back wall, and then it's recirculating through ductwork. So the inrack airflow kind of closes that loop and helps facilitate it. Problem with this is the longer you get, the more of a delta T you get from front to back, so the more heat and the more humidity you pick up.

Anders Peterson [00:26:56]:
That's why you need the right velocity and design to make sure you're exchanging that air or recirculating that air enough per hour to not have that big temp and humidity pickup in the back of your room. I mean, it's not uncommon. And that's also, by the way, why I'm a big proponent of integrated H vac systems. I prefer integrated H VAC systems over standalone dehumidifiers. Look, I've made a ton of money on standalone dehus over the years. Ran them for years. They work. I just don't think they're maybe the right tool for the job.

Anders Peterson [00:27:28]:
In a multi tier facility, you don't.

Jason [00:27:30]:
Have to sell us on integrated controls.

Cian [00:27:33]:
Yep.

Anders Peterson [00:27:35]:
Okay, cool. I mean, coupling that Dehumidification capacity in prevents a lot of hotspots in these multi tiered rooms.

Cian [00:27:43]:
It also gives you just so much more control modulation when you couple those systems in ways that are much more difficult to achieve the same or a similar result with a decoupled system. And so, I mean, for those and many other reasons, you'll always, or at least for the most part, hear me, you know, preach the integrated H VAC systems on a regular basis.

Jason [00:28:09]:
It was when I started controlling the greenhouse, my very first cannabis related job. I was able to cut the temperature differential from the front to the back in half simply by rearranging how the equipment was interacting with each other. You know, it really wasn't a limitation of what was in there, it was just a limitation of, well, you know, why are two elements running at the same time when they're fighting each other? Or, you know, how come we're not increasing some of, you know, some of the airflows when we see specific temperature rises, that type of stuff, you know, and that was 120foot run, you know, front to back. And so it's same kind of thing. I love, love this conversation, man.

Anders Peterson [00:28:47]:
Well, I've actually, you know, I study, I, I don't have a ton of experience growing in greenhouses. It's quite limited, but you know, I studied the greenhouse designs a lot. Pip also owns GGS Structures out of Canada where we, we build greenhouses all over the world, albeit that's not where a lot of my time is spent. But I love greenhouses and I still appreciate their design. I, you know, you've probably seen this too, Jason. The trend over the last 20, 30 years in greenhouses is taller and taller gutter heights. And they're doing that for a reason. They're increasing the air volume above the canopy to act as a buffer for drastic fluctuations in temperature and humidity.

Anders Peterson [00:29:28]:
That's the same approach I try and take in multi tier rooms. If you slam your racks 6 inches below the cap of your grow room, there's nowhere for air to mix and flow and rise in that space. So I'm a huge advocate of, yeah, use those tall ceilings, but still leave two to four feet above your racks so that you can actually have that.

Jason [00:29:50]:
Buffer above your top means that changes in temperature and humidity happen slower. Right? I think I was in 14 foot to the, to the gutter, which is not very tall compared to a lot of the standards right now. And shoot, the temperature rises would be, you know, three, four degrees a minute easily when we'd have sun, sun Come out from the clouds. And up here in the northwest there was very drastic changes in weather. From waking up and sunrise lunchtime to cooling off. We'd have things from frost to 70 degrees ambient outside all in the same day. So very cool. One thing you mentioned that really chimed my brain there was talking about the front of the, the, the front of the room as kind of a mixing chamber.

Jason [00:30:44]:
And I was thinking about, you know, the application of vestibules on greenhouses where some of the newer greenhouses are actually using that as some of their climate control. So they'll, they'll keep that vestibule and sometimes they're shared vestibules, which is really cool as well. They'll keep that at a fairly static environment so that they have to have less equipment inside the greenhouse. And there, you know, there's less of a dynamic impact on when that equipment is cycled.

Anders Peterson [00:31:09]:
For sure, yeah. I mean for many years people were looking at that space. I mean you've probably seen in these multi tier rooms all the handles at the front of the racks that roll them left and right. That space between essentially the front of the racks and your front wall, we call it the main aisle. And many times it was sized just for labor purposes, to get carts in and out and for access. But over the years we learned that that space is extremely valuable for climate control purposes. It's where that air is introduced, it's where it mixes. But that's not the only spacing, you know, that, that matters for the design of these multi tier rooms.

Anders Peterson [00:31:45]:
It's a good climate control in multi tier begins with a good racking layout. So I've spent a lot of time collecting that data. And so I think we're all familiar with room utilization, right? Jason, you know that metric. So you're comparing in a two dimensional view the amount of canopy to the amount of floor space typically calculated by the square footage of your benching or trays. That's from a two dimensional standpoint. But what about volumetric utilization? So all of the volume within your racking structure, whether that's one, two or three tiers compared to the total volume of your room, that metric actually has a pretty big impact on how well these rooms perform. If it's too tight, I like to say the room gets choked out essentially. There's just so much biomass that you, no matter what perfect design you do, you're not, you're not going to be pushing that analogy.

Cian [00:32:42]:
For the longest time I had two rooms going. So one was 12 foot ceilings, one's 16 foot ceilings. Both were running HPS side by side for a long time. And that worked reasonably well for the 12 foot ceiling, but not great. We ended up having to go down to like a 750 watt fixture just to kind of offset the amount of heat we were getting space wise to the plants. But the other thing that we always noticed was that airflow mixing in that room was just terrible compared to the one with the six foot ceiling or 16 foot ceiling. Sorry. And the room with the 16 foot ceiling always seemed to have easier time homogenizing the climate, keeping a little bit more stable vpd.

Cian [00:33:30]:
And hearing you say what you just said really kind of rings a bell in my head about why those two rooms performed the way they did and describing the choked concept. Because that shorter room always acted like if you got too much plant mass in there, it would choke.

Anders Peterson [00:33:50]:
Yeah, man. I think airflow is one of the most underappreciated growth parameters in a lot of these rooms. In my opinion. It's overlooked. It's obviously it's not very often quantified by many growers. It's, it's more anecdotal. Are my leaves dancing or not? I've, I've been some on somewhat of a personal mission to change that in this industry. A lot of my friends know me as the airflow nerd because my hypothesis about the whole thing is, is compared to all crops grown commercially, Cannabis is the highest light crop in the world.

Anders Peterson [00:34:25]:
I mean we, we give more micromoles of light to this crop per square meter foot than any other crop. And when we talk about energy balance in these rooms, if people are familiar with that concept, if you're not familiar with that concept, highly recommend checking out a book called Plant Empowerment. Great book. The energy balance of these rooms get thrown off if you don't have the appropriate airflow rates. So if you look at greenhouse manuals, they say give your, give your crop 1 meter per second and that's basically was that 200ft per minute. And generally that's great. Yeah. If you can give a crop 1 meter per second or roughly, you know, 200ft per minute, that's generally going to be okay.

Anders Peterson [00:35:09]:
But a lot of that is based on the energy balance of a lot lower PPFDs. So as you crank this PPFD up to balance that gas exchange and this really fast CO2 assimilation rate and transpiration rate, your airflow needs to balance that rate out. And so if you're lacking on airflow, it doesn't matter how much CO2, you're giving the room doesn't really matter how much light or how your irrigation strategy works, you're going to be limited there. And frankly, there was no research on what is the right airflow rate for this crop. So Pip, we partnered with Dr. Allison justice, who you met seeing, and we built out three research chambers at her facility, the Cannabis Research Coalition. And we're doing a two year trial studying what is the appropriate air velocity for cannabis under different PPFDs. That is fascinating.

Jason [00:35:59]:
And really what we're looking at there is kind of disrupting the boundary layer around the stomachs. Right. Anytime that we're sampling a room with sensors that are controlling or monitoring, we're not getting a great representation of what's happening at the leaf surface. And that that interaction layer is vital to optimizing plant health. Anytime that we don't have that close to matching the data that we have coming in for control and analysis, the farther we're being misled by the information that we're looking at. I'm right there behind you. As far as looking at environmental parameters, number one, before we even get into any of my irrigation crop steering, all the, all the stuff people want to get nerdy on these days or whatever, seems like it's hot. It's like we got to get back to the basics.

Cian [00:36:50]:
Yeah, for sure.

Anders Peterson [00:36:52]:
Yeah. I would say us climate nerds, like, we're not as cool as the checked out precision irrigation nerds, but I was that first. I was that first. You know, I kind of realized that because I've been a grow Dan Brockwool grower for over, you know, 10 years or whatever. And I love, I was very attracted to that substrate and that style of irrigation because I could put math to it and quantify it. And so I dove into that world and very quickly I was realizing why aren't my drybacks occurring, why I'm never sending a P2 or whatever. And so I realized that climate was my limiting factor. And that's why I dove deep into this.

Anders Peterson [00:37:34]:
You can be pushing irrigation events all day, but if your boundary layer is thick or your VPD is low, that plant not going to drink and your dryback rate is going to be super slow. Right. So if you want that uptake, you got to have a good VPD to max that what you're doing in the root zone, it's all connected, you know, it's all synergistic.

Cian [00:37:53]:
I love that you threw out and quoted plant empowerment there. It's probably one of my most quoted reference materials when I talk to A lot of people, especially anyone working in a greenhouse or trying to troubleshoot environmental questions in greenhouses, it's a fantastic resource. And you know, it's funny, I just the other day was talking to someone who was like, man, I had wish I had a little bit taller bays in my greenhouse. Just because he's having such a hard time with extreme temperatures and the height of summer causing temperature differentials in ways that he has a hard time controlling inside of his bays right now. And hearing you talk about like, you know, having some of these planned areas to have better air mixing just rings bells in my head. Think about thinking about going and talking to people on site and you know, getting to see some of these concepts right up close in person.

Anders Peterson [00:38:57]:
Yeah, it was, it was really funny in the early days around 2018 ish or maybe before in California you had all these kind of dilapidated cut flower greenhouses in California, in the central coast with 10 foot gutter heights or less, no power, you know, and people said, oh, I'm going to buy that and I'm going to make it a cannabis greenhouse. You don't see many of those left today. And I think that was a big factor. You know, it costs a lot of money to raise a greenhouse, make it taller.

Cian [00:39:24]:
Can only imagine. I kind of wanted to steer us a little bit into talking about data collection. So all of us on this show are huge data nerds, obviously. And Jason and I talk endlessly about crop registration and the values and benefits of it with the perspective that you have when you go spec out a lot of these places, when you go help people with designing these systems, what types of crop registration metrics do you track really closely to help you make decisions in these, in these facilities?

Anders Peterson [00:40:03]:
Man, that is a good question. It's changed over the years too. I think years ago I used to go overboard with data collection and over the years I've learned what is truly valuable data and what is a nice to have. Because whether it's automated data collection or manual data collection, it all has a cost. And there's such a thing as death by data too. Where too much data you get analysis paralysis. And it's hard to make a decision because at the end of the day that's what this is about is informed decision making. Faster, informed decision making and building confidence in your garden.

Anders Peterson [00:40:41]:
That's what data does for you. Well, high level, I try and prevent as many data silos as possible. That's why I was an early adopter to Arroya. I think I told them before the Show I have an AROYA screen up right next to me right now. Watching a room. If I can not have data silos where I can view it in one place, that is by far a huge, huge thing for me. Going into these facilities when it comes to like cultivation parameter data, sensor density and sensor placement is really important. If you're making these sometimes multi million dollar decisions on your cultivation strategy off of a sensor that's not in the right location and you're just trusting what you're seeing on the screen.

Anders Peterson [00:41:30]:
Trust but verify. Putting this right sensors in the right place is hugely important. And then the quantity of those sensors, you know, what is a statistically significant amount of sensors that I can feel confident about in a room to make a decision? You know, If I have 5,000 square feet of canopy in a room and three root zone sensors and one climate sensor, sorry, but that's going to be really tough to feel confident making a decision on my strategy. So obviously those are very important to me. And then coming up with very clear plans and strategies on how I'm going to collect any manual data. So having the right tools, accurate tools and systems in place to collect that data as fast as possible, as cheaply as possible, but accurately, even if you have slightly inaccurate tools, just do collect that data the same way every time. Make it consistent, you know, because if it's not consistent, it's really hard to draw conclusions. And then on the cultivar side, you know, I'm looking for maybe three general groups of cultivars to not over complicate it.

Anders Peterson [00:42:39]:
I have, you know, ones that grow really tall, really stretchy, ones that are more medium height and ones that are shorter. Look at the morphology of the crop. I look at the rooting speed. Like you guys are probably wearing Mac one takes a forever to root. So like I will take that into consideration when I'm doing my veg rotations and start it, clone it a little bit earlier so that they all catch up and end at the same time so I can flip them at the same time. Man, I could keep going on and on and on.

Jason [00:43:16]:
Yeah, kind of triggered me when we were talking about registration. Obviously I have a select couple that I really, really like to look at. Plant height is right there on the top of my list when I'm thinking about crop registration and especially in a multi tier system where couldn't count on many hands and feet, how many growers I've run into with plants growing into their lights on multi tier, coming from the stuff that I've worked with once they get an Arroya system, there's a chance that we can really help them. Um, I had a grower that was, he was just really constricted by the genetics that he could run and he was pretty, pretty down on it. And I was like, well, let's, let's try around with, you know, something that you like. And we're going to push the Internet really hard in the beginning. And first round out, he was, he was able to get, to get those plants to turn out very, very nice. Even with a little bit, a little bit of a limited rack height.

Anders Peterson [00:44:15]:
Yeah, for sure. I mean, plant height and then varying your veg time to determine your ultimate plant height is important. But if you don't know how tall that plant's going to grow kind of untouched naturally, then it's really hard to determine that veg length. Even this thing. Even with growers who have a very good crop registration program still, what I see sometimes is they're dialed in, their plant heights are good, and then they have a run where they're all sudden a change happened in the facility and all their plants are growing into the lights again. And it's a factor of your veg length too, right? I mean, or your veg room conditions. If you start optimizing your veg room, those veg times are going to shorten even more. You know, I've taken a veg room from a, well, we need to veg for four weeks.

Anders Peterson [00:45:04]:
And I'm like, why do you need to veg for four weeks in this size substrate and this methodology? Well, it's because their climate kind of was inadequate and some other propagation techniques and things. So they clean that up and all of a sudden their veg time is now two weeks. So your crop registration program has to adapt those kind of changes because now your, your veg links are all going to change as well.

Cian [00:45:25]:
I love that observation because it is one of the things that I think I have benefited the most from over my personal growing career is realizing that the way that I was doing things once upon a time, going from my propagation to a dedicated veg room where I would grow in that dedicated veg room for 3ish weeks, kind of depending depending on the cultivar and how fast it was adapting, was really more of a factor of how badly controlled my bedroom was than it was the necessity to actually do that. And once I started taking a lot closer notes on the amount of time I was spending in that room and how quickly plants rooted in when they actually got into a favorable environment in that next room, I started realizing, well, you know, maybe I should just skip that room and take my clones and just go straight into their next substrate size in that flower room and do a faster flip. And lo and behold, that those notes paid off big time because it allowed me to start increasing the frequency of my runs per year through that room just by having available space in that room free up a little bit quicker and not having to go into my, my bedroom as this extra step that prevented me and bottlenecked me from being able to, to get plants into production faster.

Anders Peterson [00:47:03]:
For sure. Man, your bedroom is the gas pedal, you know, it sets the pace. I'm a huge fan of having two bedrooms, right. So like some best practices on bedroom sizing is typically your total flowering canopy in your facility. About 20 to 30% of that should be allocated to veg canopy to prevent bottlenecks. Most competent growers can get away with 20%, but if you want some buffer and safety, maybe closer to 30%, even though that could be excessive for some. If you can, sometimes it can be nice to split that into two separate rooms because then you can create two separate kind of climates and strategies to manage those different cultivars and those different crop registration groups and kind of optimize them more in Vegas. Look, man, I get it.

Anders Peterson [00:47:50]:
Flower rooms are sexy. That's where the money is made. That's where everyone likes to be in. But it blows my mind how often bedroom design is overlooked or it's considered an afterthought in the design process. It's almost like a, yeah, the veg looks good, you know, or oh, that's, that's an easier room to engineer or design. So I'm not going to put as much time into that. To me, that's a huge mistake. Like that's what's taking your bedroom two weeks to four right there.

Cian [00:48:19]:
And. Exactly. And being able to track that and understand, you know, what the effects that were happening as a result of making the choice to not have adequate control in that room was such a big eye opening event for me. And since then, talking to so many different clients when they have these concerns where they are having a hard time transitioning from their veg space into their flower space. The first thing that pops into my mind is like how well specced is your climate control in your veg space. And that lesson that I learned is just top of my mind every time being like, you know, that once upon a time cost me a whole bunch of money, time and frustration. And I might, I venture to imagine it Might be doing the same thing to you right now. So I love that observation because it's definitely one of those things you see a lot of these days where that's kind of the, like you said, the restricting factor from people being able to scale their production a little bit more efficiently.

Anders Peterson [00:49:25]:
That in dry rooms too. Dry rooms overloaded a lot in the design. That's why. Right. They get overloaded because they're overlooked. I mean, it's a. It's actually kind of a hard room to design. So I don't, I don't blame people most of the time.

Anders Peterson [00:49:43]:
Kind of like that ratio 20 to 30% thing I said with veg. I'll say that to someone, they go, okay, so what's the ratio for dry? I've heard a million of them. None of them work. There's just so many variables in how you can design a dry room that there's no good, like rule of thumb to size them.

Jason [00:50:01]:
One time I saw a continuous dry room where there has a front and a back. Then they just loaded the plants through like a pizza oven.

Anders Peterson [00:50:13]:
I've seen people use like those conveyors from dry cleaning spots just to move stuff around. Maybe it's the most inventive one that.

Cian [00:50:23]:
I've heard of so far. Like all the coat hangers hanging up on the dry cleaning machine. That's awesome.

Anders Peterson [00:50:30]:
Yeah.

Jason [00:50:31]:
Yep.

Cian [00:50:32]:
Oh, man.

Anders Peterson [00:50:33]:
Yeah.

Cian [00:50:34]:
Well, now that we're rounding the corner into our last little bit of the day, I wanted to throw in a couple of questions we got from our live fans in today. One of them we kind of covered a little bit, touched on at least a little bit in our talk about the airflow placement, airflow mixing, things like that. But we had one specific one from Indie Buds says airflow and placement of fans and vertical growing under plant pipes with air holes, oscillating fans or something else. I essentially think he wants your opinion on that, Anders, and what you think the potential benefits those things offer. Vertical growing setup.

Anders Peterson [00:51:16]:
Great question. Thank you for asking it too. So there's a couple different approaches providing airflow in these racks. There's top down airflow, which I call supra canopy airflow. Then there's bottom up airflow or sub canopy airflow, and then there's horizontal half applications. At PIPP, we have something called Vertical Air Solutions 2.0, which is a top down solution. In fact, James Cunningham from Fog City Farms in Santa Cruz and his partner Matt Bogner, they developed that system and it was the first commercially available in rack airflow system for vertical farming. Ever.

Anders Peterson [00:51:55]:
So it's really cool history. We've sold like over 100 miles of ductwork of that initial system. We reiterated it and released it last year 2.0 with some huge improvements in velocity. And we've done a lot of studies and research on this over the years because of the amount of facilities we have access to. So here's kind of my most simplified synopsis. Haf style fans blowing across the canopy are not the right tool for the job in this room. In multi tier rooms, ultimately what happens is the canopy starts getting closer. Proximity to the lights and the plants closest to that half fan get way too high of an air velocity across those stomata and then six, eight feet down the row you get nothing.

Anders Peterson [00:52:43]:
So and you can actually see it in your Arroya water content like VWC graphs. If you put sensors along that row on a half row, you can see the different rate of drybacks as you go down the road with those fans. It's actually pretty insane to watch. So those are exactly the right tool for single level and greenhouses, but not the right tool for multi tier. Now you then have the top down or bottom up discussion. This is something that I've done a lot of research on over the years. We've done actually a triplicate study over a year in the same room with the same genetics. We did top down only, we did bottom up only, and then we did the combination of the two.

Anders Peterson [00:53:24]:
Anecdotally, I can say that the combination of the two worked better than one or the other. But if I had to pick one, I would pick top down airflow. An even blanketed air velocity from the top down through the lights across the canopy. Because maintaining an even leaf surface temperature at the top of your canopy, where most of the photosynthesis is occurring, is more important to me. And it also seems to provide the most value late in harvest. The sub canopy airflow systems, the fan and poly tubes blowing up underneath your plants showed a ton of value during stretch. They showed a ton of value in getting that CO2 to the stomata and maybe anecdotally again shortening that stretch time. So if I can get through stretch faster, that's great.

Anders Peterson [00:54:15]:
The sub canopy also really helped if you had sub canopy lighting. So if you have sub canopy lighting and you're running a four foot deep canopy compared to let's say a three foot deep canopy without sub canopy lighting, that sub canopy airflow is going to what's going to help you not get PM right. And so it's totally A necessity if you're running sub canopy lighting or intra canopy lighting, whatever you want to call it, it. But again, to kind of summarize that top down airflow, after all, my work is for sure providing the most value, something that can throw about 4ft distance down. So a good throw distance, a good variable speed velocity. But if I had the choice, I would do that plus sub canopy airflow as well.

Jason [00:55:03]:
When I first started working in here, I was getting to see a couple very few systems, just a couple systems where they were using H Vac ducting. You know, it's pretty simple, Pretty simple, you know, implementation of. Let's try to lower the velocity but get more consistent, more airflow throughout the whole, you know, the whole room versus obviously high intensity, you know, Shaffer fans that we've seen on the walls. Sure, that's great for mixing, you know, total H Vac systems, but for actually, you know, getting airflow into the canopy. That distributed systems are awesome.

Anders Peterson [00:55:43]:
Yeah, I mean just high level. We're looking for something for good transpiration and photosynthetic rate. We're looking for about 100 to 150, sorry, 100 to 200ft per minute in veg and anywhere from 150 to 300ft per minute in flower. So that number increases as your PPFD increases. Now that is where Alice, Dr. Justice and I, Allison, that's kind of where our heads are at right now is our hypothesis. With the data we've collected. It could be a little bit higher than that with higher PPFDs.

Anders Peterson [00:56:15]:
But we're going to hone in on those numbers more and we're going to release that data publicly close to the end of the year at MJ Biz for the industry to see.

Cian [00:56:26]:
That's awesome. I really appreciate also that you kind of talked a little bit about the difference between having that inner canopy or under canopy lighting. And you know what difference having bottom up airflow can make when you have those. Because I see a lot of people, I feel like overlook that that one piece when they add the inner canopy under canopy lighting on multi tier systems. And it can make a huge difference in how they're able to control, like you said, the opportunities PM has to take hold.

Jason [00:57:03]:
Especially if I'm over here telling them we don't have to de leaf as much after adding under canopy.

Anders Peterson [00:57:13]:
Hey, if it was up to me, we would never talk top and never default. But it just, you know, if I.

Cian [00:57:18]:
Get away with it, I'd never touch them. But you know, every once in a while I'm. I miss my guess on just how leafy it's going to get. And that's a bad, bad look when you get too far down that road. All right, well, that'll be the show for the day. Wanted to thank everyone for joining us today. Thank Anders for hopping on with us. This is a great conversation.

Cian [00:57:40]:
I had a lot of fun. I hope Anders did as well. Jason, do you have a good time?

Jason [00:57:44]:
It was awesome show. Best people around, dude.

Anders Peterson [00:57:48]:
I just want to say thank you guys for having me on. Like I said, I'm a fan of the show. Been listening to it for a long time. So I really enjoy joining you guys today.

Cian [00:57:56]:
Us as well. Thank you, man. Well, to everyone listening, if you have any crops during cultivation questions you want us to cover, drop them anytime into our the AROYA app. Email us@salesrooyaio send us a DM via Instagram, Facebook, LinkedIn. We always want to hear your cultivation questions. And if you're a fan of the pod, please leave us a review on Spotify, Apple Music, YouTube. Wherever you listen to the podcast today, we appreciate your feedback. Be sure to subscribe to our YouTube channel so you never miss an episode.

Cian [00:58:25]:
Thanks. See everyone at episode 137. And this is or this is a royal fifth birthday, everybody. Been in production now for five whole years. I'm sure that makes Jason feel a little bit old, but, you know, shout us out a little bit and thank us for our five years of service.

Jason [00:58:47]:
Thanks, Ian.

Anders Peterson [00:58:50]:
Happy birthday, AROYA.