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“What that means is that when you grow successive spinach cycles, the root exudates are being released into the water that build up to a point where spinach's own root exodus become toxic to itself,” explains Jake Holley, manager of the Metro Ag Research Center in Denver and pioneering researcher in controlled environment agriculture.
On this episode of Greenhouse Success Stories, Jake brings rare insight into the world of hydroponics—from tackling spinach’s infamous autotoxicity to advancing water quality monitoring with cutting-edge ORP probes. Drawing from 15 years of hands-on experience across academia and industry, Jake reveals how product validation, public education, and innovative trials at Metro Ag are lighting the way for growers worldwide. Discover why this researcher’s practical wisdom and drive to make science accessible have him shaping the future of urban agriculture, one experiment at a time.
Key Takeaways
- Grow your confidence—and your crops—by testing new products risk-free in R&D settings before you invest. Seek third-party validation for solutions and experiment boldly.
- Build hands-on experience with hydroponics at any scale. Try growing lettuce or spinach at home—simple setups and DIY methods can feed your household year-round.
- Collaborate and connect with local and global growers, educators, and innovators. Share your knowledge, tour facilities, and help raise awareness about CEA in your community.
- Tackle tough crops head-on. Use strategic variety selection, light management, and germination techniques, like vernalization, to overcome the frustrations of growing spinach and other challenging plants.
- Monitor and optimize your systems relentlessly. Integrate affordable new tech, like ORP probes, to predict issues and automate water quality management—stay ahead to boost yields and save time.
Memorable Quotes
"What that means is that when you grow successive spinach cycles, the root exudates are being released into the water that build up to a point where spinach's own root exudates become toxic to itself."
"My job is to advance and support urban agriculture, not just within Denver, but nation and worldwide. In that effort, my job really has three somewhat distinct categories: facility management, supporting academic research, and conducting trials to advance knowledge of hydroponic systems and controlled environment agriculture."
"I think providing stuff that growers can actually use and saves time and energy has been really cool for me—to see actual impacts and not just research that ends up tucked away in a journal."
Connect with Jake
LinkedIn - https://www.linkedin.com/in/jake-holley-4a83134b/
Connect with CSU College of Agriculture
Website - https://agsci.colostate.edu/about/
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Mentioned in this episode:
2025 Precision Ag Report by iGrowNews
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Transcripts
What that means is that when you grow successive spinach cycles,
Speaker:the root exudates are being released into the water that build up to a
Speaker:point where spinach's own root exodus become toxic to itself.
Speaker:Welcome to Greenhouse Success Stories. Tune in every week as we share
Speaker:conversations with growers, operators and innovators from around the world,
Speaker:providing insight into what's working in their greenhouses. We discuss
Speaker:firsthand experiences and provide insights into how these forums are
Speaker:succeeding and thriving. Special thanks to our title sponsor,
Speaker:Arnois Greenhouse, with your host, founder of Little Greenhouse that
Speaker:Could, Trina Semenchuk. Hi everyone. Welcome to
Speaker:Greenhouse Success Stories Podcast. Today for this
Speaker:episode we have Jake Holley. He is the
Speaker:manager of the Metro Ag Research center in
Speaker:Denver, Colorado. Welcome to the show, Jake. Thanks.
Speaker:Great to be here. Yeah. Great to have you. We haven't had a
Speaker:researcher on the show yet, so sure you'll be able to provide a
Speaker:very valuable set of knowledge in the hydroponic CEA
Speaker:world. Yeah. So, just to get started, can
Speaker:you explain more about your role
Speaker:as the manager at the Metro Ag Research center in Colorado?
Speaker:Sure, sure. So the Metro Ag Research center is part of Colorado
Speaker:State University, and We're one of 10 research centers that are spread
Speaker:across the state, each one providing a different agricultural
Speaker:service. So we have research centers focused on cattle and
Speaker:livestock production, some focused on potato production in the
Speaker:field, dry land, grain production. My
Speaker:specific research center is focused on controlled environment agriculture, so
Speaker:greenhouses, vertical farms, and all the little nuances that
Speaker:come along. With urban agriculture.
Speaker:One of our sayings is sometimes an urban aggression. The crop is not the crop,
Speaker:meaning that the services that urban ag provides are oftentimes
Speaker:beyond just the plant material itself. So my job is
Speaker:to advance and support urban agriculture, not
Speaker:just within Denver, but nation and worldwide. In that
Speaker:effort, my, my job really has three somewhat distinct
Speaker:categories that I work in. So the, the first one as, as
Speaker:a manager is my job is to make sure everything keeps running in the research
Speaker:center. So it's actually a really fun part of my job that I enjoy to
Speaker:troubleshoot. If we have a light or a fan that goes out or,
Speaker:you know, electrical issues, I'm the kind of first line
Speaker:to see what's going on, make fixes and justice. So there's a
Speaker:facility management portion of my job, which I really enjoy. The second part is
Speaker:supporting research from the academic staff
Speaker:at Colorado State University. So various professors and
Speaker:other scientists around the Colorado State University campus will be
Speaker:conducting experiments within my facilities. And so I provide the
Speaker:expertise and the. And the knowledge specific to my
Speaker:facility to make sure their research is successful as well as providing
Speaker:stuff like integrated pest management services and ensuring
Speaker:that their crops grow healthy in our, in our facility. And
Speaker:then my last service, which kind of blends into the second one, is as a
Speaker:research scientist, so actually conducting research
Speaker:trials looking at advancing the knowledge and
Speaker:understanding of how hydroponic systems and controlled environment agriculture
Speaker:operate. And so there's a little bit of a blend into my kind of second
Speaker:duty of supporting research as there's like a gradient between
Speaker:people that know exactly what they want to do and I'm just there to help
Speaker:support all the way to people that, you know, have a distinct goal
Speaker:they're trying to achieve and are looking for, for my expertise and how to get
Speaker:there to research that we're, we're creating and operating
Speaker:all on our own. So in a nutshell, that's, that's what I do at, at
Speaker:Colorado State. Wow, I love it. That's quite a bit of different
Speaker:hats. In your first portion that you explained, you
Speaker:know, how you're in charge of keeping the facility running, it almost sounds
Speaker:like you're kind of the research head grower of the facility. Do
Speaker:you think like that's an accurate definition for that, you know, first
Speaker:category of role that you have? Yeah, yeah, I think in a way that's,
Speaker:that's definitely true. You know, I joke around with a lot of people that half
Speaker:my job. I'm sure a lot of head growers will agree when I say half
Speaker:my job is plumbing. So yeah, it's, you know,
Speaker:fixing leaks, redesigning plumbing systems. A lot
Speaker:of what we do is chemical, fertilizer and
Speaker:nutrient solution testing. So we're constantly redoing
Speaker:drainage lines and irrigation setups. And so, you
Speaker:know, as kind of that head grower setup, I think we're all familiar with the
Speaker:movement of water within CEA environments. So certainly a big part of what
Speaker:I do and then overseeing all the other aspects to make sure the plants stay
Speaker:healthy and growing. So I really enjoy that. That portion of my job a lot
Speaker:allows me to still be hands on with plants, which is something that
Speaker:I, I think you can lose pretty quickly in the academic and
Speaker:research world. Yeah, no, definitely. It sounds like you have
Speaker:a very unique and exciting role because on
Speaker:one hand you get that practical, you know, day to day
Speaker:work where it's involved with growing plants, keeping the facility running. But then on
Speaker:the other hand, you also get to explore these research
Speaker:questions that, you know, I'm sure advance the CEA industry as
Speaker:a whole. And so you're contributing to something, you know, much bigger,
Speaker:beyond your individual facility, which is really, really
Speaker:cool, I guess I'd be curious to know how you got
Speaker:into the role you are right now. Did you start
Speaker:in the research, you know, sort of academic
Speaker:circle, or did you start, you know, as a grower or a
Speaker:laborer in the greenhouse sector? Maybe explain a
Speaker:bit more about how you got started in the CEA world?
Speaker:Yeah. So it actually all goes back to
Speaker:me waiting for a coffee in undergrad. There I was at a. I was at
Speaker:a cafe, and there was, you know, magazines on the
Speaker:wall, and Discover magazine is one that I've always enjoyed. They used to
Speaker:have a section at the back that was like, 20 facts about this, that or
Speaker:the other. And the magazine happened to be 20 facts about
Speaker:taste. And so one of the things in there was a plant called Miracle
Speaker:Fruit. It's a West African plant. It makes this fruit that
Speaker:binds your taste buds and makes sour stuff taste sweet. So cool.
Speaker:Yeah, you can, like, chew on this berry and then you can. And I don't
Speaker:recommend it because it's still very acidic, but you could, like, eat a lemon and
Speaker:they taste actually pretty good. So, you know, you could actually just buy dried
Speaker:forms of it on Amazon. But is that what you did? No, because I was
Speaker:young and naive, so I thought it would be a good idea because the berries
Speaker:spoil so quickly without processing. I figured my only way of getting one was to
Speaker:grow the plant myself. Being, you know, West African and kind of
Speaker:tropical, I was looking for an indoor area to grow plants in my
Speaker:undergraduate. So I was actually able to get a small greenhouse bench space where
Speaker:I killed dozens of these things in an attempt.
Speaker:But that was really the start for me. And it was in there that I
Speaker:decided to really pursue being in the greenhouse industry. And so
Speaker:that led for me to go into my master's degree, which was more
Speaker:focused on ornamental horticulture. And then
Speaker:actually after that, worked for a couple years as a researcher in industry for an
Speaker:LED lighting company. Back to school for a little bit, back to industry for a
Speaker:little bit, designing backyard greenhouses, and then into my role
Speaker:that I'm at today. So I think the kind of intro
Speaker:really was well fitting, kind of working in both engineering environments and
Speaker:academic environments. Kind of that background really led me
Speaker:into the. The role that I am now where it's kind of, I think,
Speaker:really well fit for. For what I enjoy doing a little bit of. A little
Speaker:bit of the building and designing a little bit of the academic research as well.
Speaker:Yeah, I Love it. It's so diverse. When was, when did
Speaker:you try growing this miracle fruit? Like, how long ago was that?
Speaker:Oh, no, I. I think it's been 15
Speaker:years, so. Oh, wow. So 15 years in this space? Yep,
Speaker:yep. So, yeah, so it was right at the very start of my undergraduate,
Speaker:my. My sophomore year. And I guess I'm curious to know, why did
Speaker:you first, like, why was your first thought to go get your
Speaker:master's instead of to go get a job? Maybe explain
Speaker:that a bit more. Yeah, so my undergraduate
Speaker:was in marine science. And so I
Speaker:was actually, upon graduating, wanted to go into a controlled environment space,
Speaker:but wasn't sure which space to actually go into. Part of me was
Speaker:actually really interested in aquaculture, and so I will, you know, I'm sure we'll talk
Speaker:about aquaponics in a bit, but really wanted to get somehow involved in
Speaker:that space. But with that being said, as, as I mentioned, I didn't have a
Speaker:whole lot of experience actually growing plants. You know, I had, I had gotten
Speaker:some experience in the greenhouse, but like, like I said, most of it was just
Speaker:learning how to do the wrong things. And it was a good experience. It was,
Speaker:you know, learning salt sensitivity in plants, learning
Speaker:watering strategies, learning that kind of stuff. So really
Speaker:valuable stuff, but from a lot of different standpoints. I really didn't
Speaker:know how to operate in a greenhouse when I was just graduating from
Speaker:undergraduate. So going back and getting more education was a really big,
Speaker:big part of really understanding how a greenhouse operates. But
Speaker:the various mechanisms in controlling the environment actually are. And
Speaker:plant physiology. So I was all kind of deficient in that coming out of
Speaker:undergrad. And the master's degree made a really big difference in
Speaker:that kind of understanding. Right. That's actually a similar path
Speaker:that I took after finishing up my undergrad in
Speaker:biosystems engineering. I really wanted to get into controlled environment
Speaker:agriculture, you know, biosystems engineering. It helps a lot with
Speaker:learning all these different disciplines of engineering and applying it to biological
Speaker:systems. But we didn't have
Speaker:any classes specifically on controlled environment agriculture.
Speaker:So before I got into industry, I started my masters as well and
Speaker:built my own vertical farm and started learning how to grow plants that way.
Speaker:So similar. I can relate to you on that a bit on that
Speaker:redirection path and going to get your master's. I think it's a good
Speaker:option for people who, you know, want to learn more, but maybe they
Speaker:didn't get that experience in university, they could find it in other
Speaker:ways in university. One comment that you just made is
Speaker:that, you know, Part of what the Metro
Speaker:Ag Research center does is it helps grow the CEA
Speaker:industry as a whole. Can you explain more about how
Speaker:that center helps to grow the CEA industry
Speaker:in, you know, let's say North America or worldwide?
Speaker:Like, is it through your research trials? What do you think is the most
Speaker:impactful, impactful thing that you guys do at that center
Speaker:that helps the industry? So I think there's a couple,
Speaker:couple big areas that I think we really help in. One that I'm really excited
Speaker:about that's going on right now is we're a site for product
Speaker:validation. So, you know, the CE industry is full of
Speaker:various products and bio stimulants and
Speaker:new fertilizers and that kind of stuff. And as a grower to,
Speaker:you know, every crop you grow is going to be monetarily important to you. Whereas
Speaker:in my operation, what the crops we grow are for knowledge. So
Speaker:we're able to take on the risk of trying new things as our
Speaker:purpose. One of the trials we have going on right now is actually
Speaker:a microbial inoculant. So there's a company based out of the UK called
Speaker:Concert Bio, they do a microbial seed
Speaker:spray that can show to help yield of crops.
Speaker:So they have a grower here in the US that's interested in trying this product.
Speaker:But you know, like any, any good, well rounded
Speaker:operation, they simultaneously want to see a third party
Speaker:try this first. And also as much as they like Concert
Speaker:Bio, they need to see someone who isn't them provide that data of how it
Speaker:impacts plant yield. So we had the plants growing right now in my
Speaker:greenhouse, we've done the inoculation and then we'll report the results back to
Speaker:these, both these parties so they can actually see what happens when
Speaker:someone like myself tries these things out. And so
Speaker:if it's successful, and I hope it works out for the best, whatever
Speaker:the best may be, we'll be providing that data and then it
Speaker:allows us to really learn more about this product
Speaker:as well as if it's successful in the realm that it increases
Speaker:yields, then the growers will be able to then apply it to their situation.
Speaker:So a way of really jumpstarting a new product
Speaker:within CEA that can actually be really beneficial to, to
Speaker:not only their bottom line, but the amount of food that controlled environments produce.
Speaker:So that's one aspect of how we're helping stuff
Speaker:worldwide is helping the UK in their product development,
Speaker:helping the North American growers and their yields and kind of bringing
Speaker:those together in a way that is fair and objective.
Speaker:In how we test that kind of stuff. We're also trying to do a lot
Speaker:with, as an educational institute to build education
Speaker:within my specific research center. We're located at a campus called
Speaker:CSU spur. So SPUR is a what's described
Speaker:as a lifelong learning center. So we have everything from, you know, field
Speaker:trips of elementary school students to professional
Speaker:people doing career development within our building.
Speaker:So that means that we're, we're hoping to really
Speaker:disseminate knowledge and everything we learn directly to growers,
Speaker:directly to students and, and building ag pathways
Speaker:for, for kids that didn't even know they existed in the first place. I mean,
Speaker:I mean, certainly for me, I don't know if you feel the same way too
Speaker:that if you were to ask me like if my job existed
Speaker:when I was in high school, I wouldn't have known it did. So that kind
Speaker:of exposure can oftentimes, you know, I think I would have
Speaker:been more interested in greenhouses as a 16 year old and not having to find
Speaker:them several years later. Yeah, no, absolutely. I couldn't agree
Speaker:more with you about the importance of education and getting the
Speaker:word out about science. Cea that was one of like the huge drivers of
Speaker:starting up local greenhouse that could. And like, why doesn't everyone in
Speaker:Winnipeg, Manitoba know about this field? Because, you know, where
Speaker:we are, it's the growing season's like four or five months out of the year
Speaker:and people are constantly complaining about, you know,
Speaker:not being able to garden all year round or, you know, not having
Speaker:different tools to grow their own food. And then I stumbled
Speaker:into this industry and I'm like, whoa, this is actually like a pretty
Speaker:significant industry that is making changes and
Speaker:evolving and innovating, you know, on a monthly basis.
Speaker:And there are some, you know, concrete solutions to
Speaker:some of these problems that people just don't know about. And one of the, one
Speaker:of the things that we're trying to do right now is actually get a greenhouse
Speaker:or you know, a very small scale vertical farm installed downtown
Speaker:in Winnipeg that has like a public space where people
Speaker:can come take tours and learn about this more. And you know, I don't know
Speaker:where your setup is and how close it is to,
Speaker:you know, people, I guess just your average day to day person.
Speaker:But our university is kind of like near the perimeter of the city.
Speaker:So there's also an accessibility issue as well. Like we've got, you know,
Speaker:greenhouses and we've got a vertical farm, but it's not
Speaker:that accessible to the average person
Speaker:if they're not, you know, going to The U of M or if they're on
Speaker:the other side of the city. So having some place downtown I think is really
Speaker:key. Have you guys experienced any kinds of those issues of
Speaker:getting the general public out to your facility or are you in more
Speaker:of a central location in your city? What's been your
Speaker:experience with that? So a little of both. So Spur is
Speaker:located within Denver city limits. So we are in
Speaker:Colorado's main population area, right at the corners of Colorado's two
Speaker:main highways, I 70 and I 25. So getting to Spur
Speaker:is very easy and it's publicly accessible. You can just walk right in the
Speaker:door and check stuff out. The greenhouse does require people to
Speaker:escort you through just for pesticide and food safety purposes. But you know, you
Speaker:can walk right up there and we're oftentimes available to let people in and give
Speaker:them tours. With that being said, Spur is located in a very
Speaker:industrial part of Denver, so you wouldn't happen to walk by
Speaker:it just due to the nature of, of the city planning. But you know,
Speaker:one of the things that we're saying is that, you know, Denver's growing fast enough
Speaker:so we're kind of at the edge of where people are in Denver and in
Speaker:15 years we expect to be more in the center. So as the city continues
Speaker:to spread outwards and we're hoping to really help and support the area around
Speaker:us to, to thrive and then, you know, it's possible that we see just
Speaker:more foot traffic in general. The other thing is, is we are co
Speaker:located with a group called the National Western center and they do
Speaker:a big stock show once a year in January. So they
Speaker:attract in hundreds of thousands of people for that event. And since we're kind of
Speaker:co located on site, we see tens of thousands of those
Speaker:visitors that, that come through our facility just due to co location.
Speaker:So we do get some of that kind of organic walkthrough one month per
Speaker:year. So otherwise. So like I said, easy to get to. But that's really the
Speaker:only time that January stock show that you really stumble upon, upon
Speaker:our building. Have you seen the impact of doing
Speaker:these tours on the general public? Maybe people
Speaker:are now considering their career path and have made
Speaker:changes because, you know, they've done a tour at Spur. Like have
Speaker:you seen any of those impacts? Yeah, so I think a lot of our school
Speaker:groups, they see just how easy it is to operate a small
Speaker:hydroponic system. And it's kind of funny because like I, I love
Speaker:supporting the growers and ensuring that they're successful long
Speaker:term. But I also feel like I really
Speaker:like a decentralized model as well. So teaching people that they can grow all
Speaker:the lettuce they can eat within about 8 square feet is kind of a cool
Speaker:thing. So we have a small demo table set up to
Speaker:show how you can build stuff at home and grow your own stuff. So
Speaker:we've seen school teachers come in and take a look at that and say, like,
Speaker:oh, this is easy enough. I could do this, you know, for a relatively
Speaker:low price at my house or my classroom. And so it's
Speaker:been exciting hearing people come back and say, hey, we actually built something like
Speaker:this. And it's like, oh, wow. So that impact has been. Has been really
Speaker:cool for us. Yeah. And I think you definitely need a
Speaker:combination between, you know, commercial cea, leafy
Speaker:green production, but also, you know,
Speaker:instilling those general skills in the public
Speaker:on what hydroponic is and how you can grow your own
Speaker:food all year long. And really, I think if more people learn how
Speaker:to grow their own food all year long, then they'll also be more
Speaker:susceptible and encouraged to buy produce from CEA
Speaker:facilities because they won't just see it as a Franken farm or, you
Speaker:know, a weird setup or, oh, that's not, you know, a traditional way to grow
Speaker:food. Like, I. I think getting these tools into
Speaker:people's hands will actually help commercial growers. I know. It's just an
Speaker:opinion I have. No, I think. I think that's true. Certainly. My.
Speaker:My brother had a funny experience the other day. He was buying
Speaker:lettuce at a grocery store, and this woman came behind him
Speaker:and started grilling him on. On what he chose. Like, why did you buy that
Speaker:lettuce? What did, you know? What about it? Was it. How much were you paying
Speaker:for that? And, you know, my brother was just like, I. I just
Speaker:wanted some lettuce, you know, and it turns out
Speaker:that, you know, they started chatting more. And this was actually an urban
Speaker:farmer that was trying to understand more about why my brother's
Speaker:making the consumer decisions that he was. And it actually led to a pretty good
Speaker:friendship. Now me and my brother head over to operation somewhat regularly. He's an
Speaker:engineer, so we're helping her kind of retrofit some of her. Some of
Speaker:her systems and improve some of her operational capacity. But I think
Speaker:on kind of your note, it's. It's given him a better understanding that, you know,
Speaker:now he thinks about the lettuce that he buys and having been to her. Having
Speaker:been to her farm and having chatted with her more and seeing how
Speaker:her system works. So. But yeah, I mean, certainly that was. That was true with
Speaker:him. Just kind of like, I just buy lettuce, you know. Now, now he's thinking
Speaker:a little bit more about where it comes from and what's in the mix and
Speaker:all that kind of stuff. Going back to your role as a researcher,
Speaker:what are some current research trials are you working on?
Speaker:Can you. Yeah. Tell us a bit more? Yeah, sure. So
Speaker:right now, all of our research is really focused on water quality,
Speaker:understanding the chemistries, and the biology within water
Speaker:systems. So the greenhouse is designed with a few different
Speaker:hydroponic systems. So we have nutrient film technique systems,
Speaker:deep water culture. We have a grow wall. We have Hank
Speaker:gutter systems for fine crops and berries
Speaker:and that kind of stuff, and everything's plumbed out. So we have
Speaker:separate repeatable trial areas that we can try different fertilizer and
Speaker:inoculant strategies. And so right now, as I mentioned before,
Speaker:we're doing trial with Concert Biome on their microbial
Speaker:inoculants. The other big piece of work we're doing right now is really
Speaker:investigating how to use peroxides within
Speaker:hydroponic systems and how their effects can differ between
Speaker:conventional and organic systems and seeing kind of how those.
Speaker:Those different dynamics not only affect the plant yield, but also the
Speaker:system operation as a whole. So just on the hydrogen
Speaker:peroxide note, what are you expecting the results
Speaker:to be like? Are you expecting, you know, by
Speaker:introducing hydrogen peroxide into an organic
Speaker:hydroponic method, are you expecting to see a decrease in
Speaker:yield? And why, and what do you think that means
Speaker:for organic growers using
Speaker:hydrogen peroxide? Yeah, so this all
Speaker:started with me talking to aquaponic growers. You know, aquaponics
Speaker:is, you know, obviously it's a coupling a
Speaker:fish production system with hydroponic system with
Speaker:also a microbial system as well. So the fish
Speaker:produce the waste, microbes mineralize that waste into a plant uptickable
Speaker:form, and then the plants then uptake that stuff. Within
Speaker:recirculating aquaponics systems, the parameters of
Speaker:fertilizer concentrations and ph and
Speaker:various attributes are fundamentally different than they are in conventional
Speaker:systems. So just as a brief example, you know, with our conventional system,
Speaker:we target 150 parts per million nitrogen, and we run it at a ph of
Speaker:5.8 within our aquaponics system for the health of the
Speaker:fish. We're targeting closer to 40 parts per million nitrogen and
Speaker:a pH of 6.8. And that. That is due to that
Speaker:kind of compromise you have to build between Fish health and plant
Speaker:productivity. So within both those systems, you know,
Speaker:there's this long kind of held belief that aquaponics systems hold their own slight
Speaker:reduction in yield compared to conventional, but very similar in
Speaker:overall plant performance. Yet within kind of conventional
Speaker:knowledge, it seems a bit odd that a system with such
Speaker:different. If you were to run a conventional system with 40 parts per million nitrogen
Speaker:and a pH of 6.8, you wouldn't expect to have, you know, particularly
Speaker:great results with your plants. So we're really interested in kind of exploring
Speaker:what, what's going on in particular with these systems. So with
Speaker:hydrogen peroxide, it's something that's going to affect a variety of things. It's going
Speaker:to break down organic matter, it's going to reduce microbial
Speaker:populations, it's going to have an impact on nitrate
Speaker:forms or ammonia to nitrate ratios.
Speaker:So we really wanted to explore how adding something like that into an
Speaker:organic system would differ from a conventional system. It's important to note that
Speaker:we are decoupling our aquaponics system. We don't want to be adding peroxides directly into
Speaker:the fish's environment. So we take a bit of the
Speaker:aquaponic water, put it in a separate reservoir and do our treatments there. So really
Speaker:trying to explore if there's something going on within the aquaponic water
Speaker:that is truly beneficial and whether or not
Speaker:hydrogen peroxide knocks that out. Within a conventional system, proper dosing
Speaker:of peroxides can increase oxygen, reduce fouling, reduce
Speaker:algae growth, all sorts of good things. So a lot of growers will use
Speaker:it just from a logistics standpoint, making their operations
Speaker:less prone to failure as well as easier to clean. So we want to see,
Speaker:you know, is there fundamental differences between these kind of peroxide
Speaker:applications within a, within a hydroponic system? Yeah. And,
Speaker:you know, I, I've helped quite a few people get started with vertical farming
Speaker:setups. And, you know, lots of these growers are using
Speaker:hydrogen peroxide, but I'm not as familiar with
Speaker:aquaponic farming. Is using
Speaker:hydrogen peroxide in an aquaponic farm
Speaker:pretty standard? It's not because most of them are
Speaker:recirculating. So, yeah, that doesn't get used within
Speaker:decoupled systems. It's more interesting because within
Speaker:aquaponics, you have a lot more organics in the, in the water. And we are
Speaker:seeing that impact on, on fouling. And, you know, the
Speaker:amount of clogs we have in our system gets dramatically reduced. But it's not
Speaker:a standard practice within the aquaponic community.
Speaker:Okay. So when you have been doing
Speaker:these research trials and you know, just with growing in your
Speaker:facility in general, what kinds of. And I know you said actually at
Speaker:the beginning of this podcast that you feel like most of your job is plumbing.
Speaker:So what kind of challenges have you faced with growing?
Speaker:Can you explain of us an area when you had a huge
Speaker:issue with growing some crops and you know what the issue was
Speaker:and talk a bit more about that? Yeah, yeah. So
Speaker:kind of on this note and kind of tangentially related to this
Speaker:topic as well is spinach. Oh, spinach.
Speaker:Yeah, I was gonna say, like we wanna talk about issues. Growing spinach is,
Speaker:is an easy one for I think everyone to talk about having issues with. So
Speaker:we're, we're very interested in growing spinach due to the fact that it's popular,
Speaker:but had tends to be very tricky to grow hydroponically within this
Speaker:peroxide realm. There's a lot of
Speaker:theories around autotoxicity being responsible for why we
Speaker:see pythium outbreaks occur within spinach. So what
Speaker:that means is that when you grow successive spinach cycles,
Speaker:the root exudates are being released into the water that
Speaker:build up to a point where spinach's own root exit, it's become toxic to itself.
Speaker:And so one of the areas we're looking to explore is whether
Speaker:or not peroxides and you know, advanced oxidation systems can
Speaker:break those down and allow spinach to grow healthy long term
Speaker:and avoid a lot of its, a lot of its issues, particularly around root diseases
Speaker:for these plants. For us, just because of how we operate in a research
Speaker:environment, we grow great spinach and it's because we grow one crop
Speaker:cycle and then we have to re randomize treatments and that involves completely draining out
Speaker:reservoirs, cleaning and then reseeding. So when it comes to
Speaker:growing spinach, we don't have a lot of issues. However, we do have a lot
Speaker:of issues when it comes to germinating spinach. So spinach germination has been
Speaker:one that we've had to work a lot on. And so
Speaker:initially we were growing a variety called space. It's pretty
Speaker:common. Just putting it in our plug trays as we usually do, watering them.
Speaker:And we had two major issues with, with it, one being
Speaker:germination success rate. So we were getting something like 40
Speaker:to 60%. So half of a tray would come up, which was fairly
Speaker:problematic. Somewhat easy to avoid by oversowing, at least within a research environment.
Speaker:So plants we need. But perhaps more problematic was
Speaker:germination emergence timing. So even though we would get,
Speaker:you know, 40 to 60% germination. We get some germination that would
Speaker:occur, you know, 10 days after planting or five days after planting, and
Speaker:some that would be 18 days after planting. And when it comes to research
Speaker:trials, you know, age of a plant is, is critically
Speaker:important to how big a plant is. So that's where.
Speaker:We really needed to tighten when the, the emergence actually happened within
Speaker:our spinach plants so we could have nice uniform plants that are all the same
Speaker:age, all the same size to really test our, our stuff out.
Speaker:Well, so there was kind of three different breakthroughs. We
Speaker:had to kind of really help our germination out with spinach. One
Speaker:was just starting with a better variety. So we did some variety trials
Speaker:and we, we came upon a variety called Tercier that
Speaker:generally germinated just a lot better and a lot more consistently than our
Speaker:systems. So it wasn't perfect. So the next thing we tried
Speaker:was, you know, even though we're covering these seeds in our systems, we had a
Speaker:concern that there was still some light getting through. So we started covering our seeds
Speaker:with, with opaque coverings for 48 hours after planting. That
Speaker:helped a little bit more. So we were starting to get a little bit more
Speaker:germination percentages. The consistency and timing was still a bit off,
Speaker:though. So we ran another set of trials looking at a number of different
Speaker:methods, and we found a vernalization method that worked for good.
Speaker:So we'd sow our seeds, we'd stick them in the refrigerator for
Speaker:48 hours, so two days, and then put them out in our normal seedling trays.
Speaker:So that vernalization also kind of doubled as our, as our dark
Speaker:period as well, being in a dark fridge. And now we're seeing
Speaker:germination that's close to 85%. And it's all coming up in
Speaker:a relatively tight time window. And that's really helping our
Speaker:trials out. So that kind of combination between choosing
Speaker:the right variety, light manipulation, and temperature
Speaker:control has really allowed our spinach germination to be
Speaker:a lot more, I would say tolerable is the word I would use.
Speaker:Anyone who's familiar with pelleted lettuce knows it's like three or four days for
Speaker:a nice uniform crop of lettuce, where our spinach
Speaker:crop is still 80, 85%, but at least that'll get the job done
Speaker:compared to, to what we were doing before. What made you think to put it
Speaker:in the fridge? So that was, you know,
Speaker:one of our research associates had done some research
Speaker:on, on this as well, kind of looking into different strategies. You know,
Speaker:vernalization is really common with a lot of, with a lot of crops
Speaker:within spinach. Spinach is known to be very frost tolerant. It's, it's one
Speaker:of those crops that grows really well outsource outdoors kind of on the shoulder season,
Speaker:so kind of first thing in spring and last thing in fall and has
Speaker:that tolerance. So the other thing is, is it also doesn't like getting too
Speaker:hot. So it doesn't grow well in, in, in high heat. And so
Speaker:within the greenhouse environment it can get kind of hot, especially in the summer.
Speaker:So kind of a combination of those factors led us to explore
Speaker:using that kind of temperature control. What temperature do you keep it
Speaker:at? In the, once you take it out. Of the fridge, we just throw it
Speaker:in the normal greenhouse. So, uh, we're, we're trying to hang around a
Speaker:74 degree set point at the greenhouse. Okay.
Speaker:Very, very interesting. Growing spinach, it's not for the faint
Speaker:of heart. It can get, it can be very frustrating.
Speaker:So per trial where you're growing spinach, how many,
Speaker:what do you call, you don't call them heads. Would you call it like a
Speaker:head of spinach rosette? Yeah, I don't know. Robosetta,
Speaker:Snit Yacht. How many plants do you think you're growing at a time?
Speaker:So with our system, we have, like I said, three different systems
Speaker:that we're growing leafy greens in. Our NFT system is
Speaker:540 plants. Our deep water culture system,
Speaker:depending on how we set it up, is around three or 400. And then we
Speaker:have some grow walls that are 360. With spinach,
Speaker:it generally occupies about a fifth of our grow space in any given
Speaker:system. So we're looking somewhere around, you know,
Speaker:150 to 200 Spanish plants per trial that we're growing.
Speaker:That's pretty good. Yeah, it gives us, it gives us a really good sample size.
Speaker:I feel like we're always able to provide pretty confident results
Speaker:given, given the number that we're growing because, you know, a lot of research trials,
Speaker:you're growing something like 20 plants, so. Yeah, exactly. So 150,
Speaker:200. That's pretty good for a research trial. Yeah, yeah. Having a, having
Speaker:a thousand plants per, per research trial really gives us a lot of confidence that
Speaker:we're providing good data to growers. Yeah, for sure. In your
Speaker:greenhouse, is it all climate controlled under one
Speaker:zone? Like, is it, are the grow walls. The NFT is everything
Speaker:in one general area? Yeah. So we,
Speaker:we operate just a single zone, 2400 square foot greenhouse.
Speaker:So it's a little bit on the smaller side, but it's, like I said, big
Speaker:enough to get a lot of work done. And it's all under the same, same
Speaker:kind of climate control. So the other thing that we're able to do with this
Speaker:as well, which is kind of nice, is compare how the different systems perform against
Speaker:one another. So you can see how the same crop planted in the
Speaker:DWC versus a NFT system actually grow.
Speaker:And the way we currently have things plumbed out, although we might change this,
Speaker:is they all are also sharing the same nutrient solution between
Speaker:treatments. So if we're doing a conventional treatment with peroxides in it,
Speaker:those grow walls, the deep water culture beds and the IoT systems all share
Speaker:a common reservoir. So we're seeing that that same kind of nutrient
Speaker:treatment applied to all three systems. So it allows us to compare stuff pretty well.
Speaker:What do you think the pros and cons are for each system?
Speaker:Are you, are you comfortable with sharing that? Yeah, yeah,
Speaker:because this is actually an area that I've noticed a lot of change recently. So,
Speaker:you know, if you go back 10 years, deepwater culture was really
Speaker:common within big, big greenhouses. And you know, I think
Speaker:it, it made a lot of sense. You know, there was a greenhouse in upstate
Speaker:New York that I used to visit regularly that had, you know, 100
Speaker:yard kind of stretch of deepwater culture plants. And you would see
Speaker:it on one side and you would physically just with your hands, push the entire
Speaker:crop all the way across the greenhouse to put in X trays. And then the
Speaker:other side is where the harvesting was taken, where you could take those out. You
Speaker:know, I toured a bigger greenhouse that one of my friends worked at where they
Speaker:actually had, you know, what I refer to as a lazy river for their lettuce.
Speaker:So they would take them out, put them in this lazy river, it would float
Speaker:down to the packing house and that's where they'd be able to pack stuff. So
Speaker:from a logistic standpoint, you know, deepwater culture is really easy to
Speaker:automate. And so we saw that really being
Speaker:advantageous to cutting down on labor costs and, and doing things at
Speaker:scale a lot easier. With that being said, I've seen a shift really,
Speaker:really big in the last five years, I would say, because, you know, I, I
Speaker:had been in a greenhouse that was brand new, that was deepwater culture. That
Speaker:greenhouse actually got shut down recently and all the greenhouses that I've seen being set
Speaker:up are all NFT systems, all on
Speaker:automated seeding and harvesting systems. So
Speaker:you know, we're kind of in the old fashioned, we move our NFT systems by
Speaker:hand and everything like that. But for what I'm seeing
Speaker:a lot of now is that these systems are automatedly moved around with robots
Speaker:cleaned with, with automated systems seeded with auto transplanters.
Speaker:And I think the overall yield to doing this
Speaker:correctly and being able to maximize space has been
Speaker:effectively demonstrated in industry that, that seems to be now the way to
Speaker:go is if you can do automated nft, that seems to
Speaker:be the most most efficient way of doing it. So, but it all comes
Speaker:down to how you're saving on labor and how you're, how you're able to
Speaker:create these kind of flow through systems to really minimize
Speaker:the amount of physical handling you're doing of your system. So, you
Speaker:know, I think pros and cons for each are Deepwater culture
Speaker:tends to be a lot easier just in a number of different regards. But
Speaker:NFT systems tend to be higher performing but
Speaker:they require a lot more kind of infrastructure in place that can
Speaker:be more difficult for first time or small scale growers to set
Speaker:up. So there's even you know, simple things that you know, when
Speaker:we get a line clogged or a pump go out, you know, you notice on
Speaker:the NFT system within hours. Whereas the DWC system is a lot more
Speaker:resilient to any kind of breaks or malfunctions just
Speaker:because you're, you're sitting in a bed of water that if, if you just shut
Speaker:everything off should be good for two or three days. Whereas your NFT system, you
Speaker:can kill a plant over the course of the day if you don't catch these
Speaker:kind of issues. So you know, much like cars, NFT systems I think
Speaker:are showing to be a little bit more high performance. But with that comes a
Speaker:lot more attention to detail. You know, being able to, to, to
Speaker:scale up in, in a way that makes sense. So that's kind of the differences
Speaker:that I've seen. I think both are still very relevant in, in today's, today's industry.
Speaker:And how about the grow walls? So the grow walls are interesting because
Speaker:they're, you know, within controlled environment agriculture.
Speaker:There's a big diversity in how we're growing plants. So the grow
Speaker:walls we're using are from a company called Harvest Today. Logistically speaking, they're some of
Speaker:the easiest vertical systems I've ever worked with. So really
Speaker:easy to set up, really easy to take plants down, harvest, process
Speaker:them through. You know, they're able to, we have them in the back of the
Speaker:Greenhouse, which works great because we'd only be able to put something like,
Speaker:I don't know, 40 plants horizontally,
Speaker:whereas we're doing 360 vertically. So within
Speaker:areas that we're were constrained by space or other
Speaker:constraints, you know, those work really fantastic. Within a
Speaker:greenhouse, you know, we do have to consider light limiting factors, you know,
Speaker:light limiting and stuff like that. So going vertical within a greenhouse
Speaker:does have its, have its advantages in plant density, but its drawbacks in
Speaker:how you manage that crop. So I think for indoor areas,
Speaker:having vertical systems makes a lot more sense for stuff like
Speaker:airflow. So if you're indoors, having vertical walls I think
Speaker:scales better than having shelves within systems.
Speaker:So it really comes down to application. But as far as plant performance
Speaker:goes, yeah, the grow walls, they work great for, for producing large, healthy
Speaker:plants. What research are you most
Speaker:excited to conduct in the future? Like what are you
Speaker:excited? Yeah. What are you excited about? Emerging research that's happening.
Speaker:And where do you see the Metro AG Research Center? Where
Speaker:do you see your greenhouse expanding in the future?
Speaker:Do you have any plans or things that you're excited and willing to share?
Speaker:Yeah, yeah. So we're, we're really excited to be
Speaker:investigating a new probe that we're seeing more and more deployed within
Speaker:controlled environments, which is oxidative reductive
Speaker:potential probes. So ORP is the term for that.
Speaker:It's, it's a proxy, much like EC is. It's kind of telling
Speaker:you in general what's going on, but not necessarily specifically. So
Speaker:it's paying attention to how much, you know, oxidation versus reduction
Speaker:the water has going on. So these can be affected by a number of different
Speaker:things. So just as a simple example, as the name implies, if you have
Speaker:stagnant water and you introduce oxygen to it, that ORP reading is
Speaker:going to go up because you have a higher oxygenation potential. Likewise, if you have
Speaker:a lot of degradation or organic matter, matter that's
Speaker:decaying within a system, that's going to create much more of a reducing potential. And
Speaker:so that number is going to go down various products. So peroxides is kind of
Speaker:how I got into this, can actually raise orp. And so
Speaker:we're looking at whether this is a feasible way of monitoring
Speaker:or dosing or being able to track other parameters within hydroponics.
Speaker:So dissolved oxygen sensors are fantastic, but they're a little bit
Speaker:more expensive than ORP sensors. So within our
Speaker:systems we have dissolved oxygen sensors that we use to monitor stuff. It
Speaker:works great. Is ORP a tool that's a little Bit cheaper that can provide
Speaker:a similar service to a dissolved oxygen sensor in terms of
Speaker:understanding if you have a aeration system that goes down or
Speaker:something like that can or p pick that up relatively easily and
Speaker:reliably. Also, you know, in the case of spinach,
Speaker:if you have something like root rot breakout, is ORP going to be able to
Speaker:pick that up sooner than you normally would with other
Speaker:opera with other kind of stuff like when you pick up before you would pick
Speaker:up the plant and notice that it has root rot or before it has the
Speaker:kind of wilting and stuff associated with it and then a combination of these things.
Speaker:Is there something where if you start to see a decrease in
Speaker:ORP due to microbial activity, can we sustainably
Speaker:dose in a sanitizing agent like hypochlorite or
Speaker:hydrogen peroxide to remedy that in real time and have
Speaker:that being an automated process that you don't have to be concerned or worried about?
Speaker:So that's kind of an area that we're, we're open to explore. There's not a
Speaker:whole lot of information about it from the horticultural side. There's a lot from wastewater.
Speaker:However, the paradigm that the wastewater people operate under is, is
Speaker:fundamentally different than we as growers operate under because a lot of the
Speaker:wastewater industry is either really trying to select certain processes of
Speaker:nitrification or is really good for monitoring nitrification, which could be important
Speaker:for organic or aquaponic people. But then they also are trying to do
Speaker:sanitation with it. And they're. So they're either like really
Speaker:trying to push things one way or the other way within a hydroponic system. We
Speaker:kind of have both things going on at the same time. So it's a little
Speaker:bit trickier to try to impose some of these same, same
Speaker:paradigms that they use. So it's good that the wastewater industry has a lot of
Speaker:experience with these kind of probes, but the rules are different within a hydroponic
Speaker:setting. And so we're excited to see if we can have some
Speaker:breakthroughs or some, some better management techniques using these
Speaker:kind of, these kind of probes in a hydroponic setting. Okay, so two questions
Speaker:that popped up with that. Are you
Speaker:partnered with an existing, you know, supplier of these
Speaker:probes who may have been currently targeting the wastewater sector
Speaker:and are now wanting to use their probe in a hydroponic
Speaker:setup and want you to do that testing and validation, or
Speaker:have you created your own probe? So we are
Speaker:partnered with a company that is looking to
Speaker:explore application within hydroponics. Hang.
Speaker:So there is A company that comes actually from
Speaker:environmental monitoring around petroleum industry sites. So
Speaker:they developed a pretty low cost or sensor that
Speaker:they dropped down into groundwater wells. And anytime you have
Speaker:petroleum contamination, it'll affect orp. So they're able to really
Speaker:quickly locate and be able to send back
Speaker:good data on controlling the spread or plumes of
Speaker:petrochemicals within the environment. So because of that, they've developed
Speaker:low cost IoT solutions that allow really easy
Speaker:controlling and monitoring that can go into hydroponic
Speaker:systems. So it's kind of an easy new application for them
Speaker:to be able to apply something that kind of does the job that
Speaker:we already wanted to do. Monitor big swings of fluctuations within
Speaker:hydroponic systems in kind of this, this kind of new
Speaker:scenario. What would you expect the market price
Speaker:to be for an ORP probe if the average grower wanted
Speaker:to get it installed in their hydroponic farm? Like let's say the trial, it
Speaker:goes great. You can use this probe to predict
Speaker:oxygen levels and, you know, reactions in the plant. What would
Speaker:a grower have to pay, do you think, if you had to guess? So right
Speaker:now there's, there's stuff on the market that you can buy and implement. We're actually
Speaker:seeing a couple companies that actually offer these, these already within the
Speaker:hydroponic realm. So they're very similar in price to what you'd pay
Speaker:for a PH or an EC probe. So very,
Speaker:very cheap. About a hundred dollars. Yeah, yeah. Okay.
Speaker:In comparison to like a full capital investment to start with a vertical farm.
Speaker:That. Yeah, that part I would say is very cheap. Yep, yep, exactly. So the
Speaker:probe itself is $100 that you have, of course, some, some drivers and stuff that
Speaker:you need to plug stuff into that's going to be, you know, a couple hundred
Speaker:dollars, something like that to get the full system integrated. But it's not overwhelmingly
Speaker:expensive. It's very much in line with your other water monitoring equipment.
Speaker:So the ones that are commercially available now, have they done
Speaker:research trials with like a third party similar
Speaker:to yourself, or do you know if they have or not? Maybe, or
Speaker:maybe you don't know if they have. So I've talked to
Speaker:Bio Safe, which is a company that does a lot of the peroxide products.
Speaker:They've looked into using ORP as a method. And I know just from
Speaker:the sensor side of things, some other companies are looking at developing
Speaker:those, those sensors. So I don't know specifically what's going on, but I do know
Speaker:that we're seeing new products pop up every day. So I
Speaker:know that there's there's kind of a little bit of a buzz going on around
Speaker:whether this is going to be kind of a new thing within the industry.
Speaker:Okay, well, Jake, this has been a fantastic
Speaker:conversation. You are obviously very smart and I am
Speaker:looking forward to talking more with you in the future. But
Speaker:I've got, you know, one last question for you here,
Speaker:and that's what is your proudest moment as a grower and
Speaker:as a researcher? Okay. Well, certainly as a
Speaker:grower, you know, as I mentioned, coming out of undergraduate, I knew very little
Speaker:about growing. And then a year or two into my PH or my master's
Speaker:degree, I was helping with, with some classes and
Speaker:my major professor, my advisor got in some
Speaker:chrysanthemum cuttings and he handed me the box and he goes, I need
Speaker:flowers on, you know, like January 15th, February 8th
Speaker:and April 15th. Go. And you
Speaker:know, to understand, you know, okay, so they were just cutting so
Speaker:to, to take it through the entire process of, of rooting them,
Speaker:potting them up, getting the right, you know, dark
Speaker:period to start for the flower. And then there was a big gap and he
Speaker:actually, with the numbers that he gave me, there wasn't actually enough plants for all
Speaker:three. So. And there was a big gap between like the February date and April
Speaker:date. So then I had to set up some, some stock plants to actually propagate
Speaker:from, to get up to the numbers that I needed and then was able to
Speaker:deliver all those on time. That was really, for me, the big moment where I
Speaker:felt like I knew how to grow plants in a greenhouse. So that's,
Speaker:I think, proudest moment as a, as a grower and as a
Speaker:researcher, you know, I think providing stuff that, you know,
Speaker:a couple examples of, you know, I did some research
Speaker:in industry which looked at how to best apply lights over different
Speaker:photo periods and to be able to see stuff that growers can be really
Speaker:applicable and easy to use and saves time and energy has been
Speaker:really cool for me to actually provide useful information for people. So just
Speaker:kind of see those actual impacts and not just stuff that ends up in a
Speaker:journal and tucked away has been, has been really big for me as well.
Speaker:Yeah, that's what I love so much about your position is you're
Speaker:doing research, but your research is going to be
Speaker:applicable to industry because you have part partnerships
Speaker:with commercial providers or equipment providers who are in the
Speaker:industry where your results are
Speaker:directly going to impact how their technology comes
Speaker:into use. In cea, which is super cool because,
Speaker:yeah, a lot of research, you know, it could just be a journal article
Speaker:or something written in a paper that no one ever uses. Thank you so
Speaker:much for your time. I think you had clear, clearly a
Speaker:wealth of knowledge and information on this topic,
Speaker:and I'm really actually looking forward to chatting more
Speaker:with you in the future because I would definitely love to explore how
Speaker:we could collaborate on some projects.
Speaker:But thank you so much for your time and thanks for being on the show.
Speaker:Yeah, thanks for having me. I hope you enjoyed this
Speaker:episode of Greenhouse Success Stories, hosted by Trina Semenchek. Thank you. Thanks to
Speaker:our guests who make this all possible. Special thanks to our title sponsor,
Speaker:Arnois Greenhouse. To read the full show notes for each episode, which includes
Speaker:an episode summary, key takeaways, and guest resources
Speaker:mentioned, please visit greenhousesuccess. Com.
