Episode 140: The Sustainability of Peat and Other Substrates with Dr. James Altland

Welcome to the Cannabis Cultivation and Science Podcast. I'm your host, Tad Hussey of KISS Organics. This is the podcast where we discuss the cutting edge of growing from a science based perspective and draw on top experts from around the industry to share their wisdom and knowledge. Now, before starting the podcast, I want to remind folks that we do have a Patreon for growers who want access to the unedited podcast weeks earlier, as well as extra content on our own grows, virtual hangouts, a private Discord channel, and more that we don't share publicly. You can check it out for a free trial if interested, to see if it can help you with your cultivation goals. Now, my guest this week is Dr. James Altland. Dr. Altland is a research horticulturalist and the research leader for the USDA ARS Application Technology Research Unit, also known as the atru. Although the role of the ATRU has historically been to develop new pesticide application technologies, it has shifted its focus in the last five years to developing CEA technologies while leading a team of 10 scientists in various aspects of CEA from entomology, plant pathology, engineering and horticulture. Dr. Otland's expertise encompasses the development of substrate technologies for containerized plant production. With collaborations at Ohio State University, this has recently evolved into the Microbial Community analysis of container substrates. Now onto the show. Hi James, thank you so much for coming on the show today. I really appreciate it.

Yeah, thank you for inviting me, Tad. I'm glad to be here.

I caught most of your presentation that you did for the American Society for Horticultural Science talking about the long term sustainability of peat in horticulture, and this is, I think, such an important topic. But can you tell us a little bit about yourself and why you were selected to be the speaker on this particular topic?

Yeah, sure. So I'm a horticultural scientist for the U.S. department of Agriculture, what we call the Agricultural Research Service. So I've been working with soilless substrates for about 20 years and a lot of my research has been with Douglas Firbark when I worked out at Oregon State University, Pine bark here on the east coast. And I've heard all the rumblings about the use of peat and the sustainability of peat and its impacts on climate change, etc. And you know, Pete's an excellent substrate, but, you know, I didn't really pay much attention to that. It wasn't really what I was focused on. And then I attended a conference up in Quebec last summer on peatland restoration and what I saw and what I experienced at that conference and going out and Visiting some of the peat bugs did not mesh well with what I'm hearing in the media. So what I wanted to do was to. And a lot of what I hear in the media is, is a lot of, you know, a lot of diatribe, a lot of con. You know, I hear a lot of comments that aren't substantiated by facts. So what I want to do is add some context, some factual basis for this conversation and let growers and others make their own informed decision about, you know, the sustainability of peat versus all the other alternatives that we might have in lieu of peat.

Yeah, and I absolutely want to talk about some of the alternatives that you mentioned, like the wood fibers, the pine bark. Coco Coir obviously is a big one. But when we talk about substrates, you also have to include things like perlite and rockwool, which we know are not very sustainable. But. Yeah, so for me, as someone who grew up in the nursery industry and has been in the horticulture industry pretty much my entire life, I've. I've heard very mixed things about peat. You talk to one person and you hear that peat is destroying the world huge carbon footprint and it's quite damaging. And then you talk to other people, you know, you know, you talk to, you read what's on the Premier Pro Mix website, for example, and it'll say that peat is quite sustainable. And it seems like there's science on both sides. And it's very confusing for an average grower to figure out what if they want to be sustainable and be environmentally conscious, what our options are. And in your presentation right out at the beginning, you share some headlines from the New York Times saying why gardeners should stop using peat and what they should use instead. You have one from Better Homes and Gardens talking about how Pete's a sore point in the industry due to its lack of sustainability. And then National Geographic one that we talked about before the show, the headline to their article is Potting Soil has a Dirty Secret. So there definitely is a media push towards moving away from Peter that Pete is, is really harming our environment. What would you say to all that?

Well, I don't have a dog in this fight. I don't get any money from the Pete industry. They don't pay me anything. I can't as a, as a, as an employee for the federal government, I can't accept money from outside interests like that. So what I would like to. What I'm trying to do with some of these presentations that I've done is just share the facts and I think when you look objectively at the facts that you come to the conclusion that, yes, there is a price tag environmentally for using peat, but oftentimes the price tag for using these alternatives that are touted are much higher. And another thing I'd like to do is to put in the context of what, how much, what is the carbon footprint of growing media or peat specifically, relative to some other human activities, when you look at it from that perspective? And one thing I tell people, we're not using PETE or other substrates to power private jets and luxury yachts. We're using this to grow food. We're using it to grow forest seedlings for reforestation, and we're using it to grow plants for the urban landscape, which have well documented benefits on human wellness and mental health and all sorts of things. So you can say, well, we don't need petunias, but, you know, the truth is, even ornamental plants have value to our society and to human health. So we're using these soilless media for very good reasons. How can we do it in the most sustainable way possible? Well, we can't do that. We can't make those decisions without facts. So that's what I'm trying to share with people is just what does the data tell us in terms of the sustainability of these various growing media?

Well, I want to get into the data, but I really think there's two things that we need to look at when we're talking about substrates. And the first is first and foremost is performance. And so before we get into, like, the sustainability of these substrates and in terms of performance, where does peat rank on this? On the scale of horticultural substrates, Pete's the gold standard.

And, you know, you can read. I could, I could fill this room with scientific studies, you know, looking for alternatives to peat. And there's a reason why we don't have a good one yet is because peat generally outperforms other substrates. The way that it is processed, it, it's very uniform, it's very predictable. We've been growing with this for over 60 years now. We just gotten very good at engineering the substrate, developing fertilizer programs and irrigation programs so that we can optimize the growth and development of our crops. Now, when you change that to a different material, oftentimes it requires more fertilizer, more water, more time. And those all cost carbon, energy, time, dollars, everything, labor. So in terms of just ranking the substrates, peat really is the gold standard.

Yeah, I just want to get that out there for folks because I think that's really Important. I know, as myself and my company has searched for other alternatives for Pete, we keep, we keep falling short because ultimately we want to create the best product, you know, for growing plants. And at the end of the day, Pete really is that standard. And one other thing, and this is probably a little bit outside of, you know, your, your world, but in our, in my industry, by starting with peat moss, which is so acidic, it allows me to add more cations, more fertilizer essentially, into that media so that I can create a more fertile mix than I could with Coco Coir, for example. Because Coco Coir, starting with a neutral pH, starts pushing us into outside of range, optimal PH ranges for nutrient uptake. So with, with peat moss, I can add biochar that's alkaline, I can add compost that's alkaline. I can add a variety of different fertilizers to reach a PH range that's still quite acceptable for nutrient uptake. So I just wanted to mention that for the folks that are listening, because I know that a lot of people that grow, grow similarly to the way we do in terms of creating a very fertile soil mix in this industry. So I just want to throw that out there.

Yeah, you know, you're absolutely right. We're very good at raising the PH of substrates. You know, a small degree like Pete and pine bark falls in that same category, generally has a low pH. We're very good at elevating the PH to the right level. When you have to lower the ph because your substrate starts out already too neutral or basic, that becomes very difficult. We can do it, but then we run into a lot of other problems. So it's not nearly as neat and clean and as when you start with a low PH substrate like peat. You're exactly right.

Great. Well, let's, let's dive into the data then. So just from looking over your, your presentation here, where, where would you want to start? Do you want to talk about the, the peat bogs themselves or did you want to get into some of the data around carbon sequestration and, and that sort of thing?

Well, I think, I think it's good to start with peat bogs. And what is a peat bog or a peat land and why are they. So does that factor in to, you know, the global climate change? Because that's really what's driving this. It's not that. Oh, I, I want a substrate that works better than peat. You know, there's a lot of information out there, a lot of disinformation about, you know, how Using peat affects climate change. So that might be a good place to start if that, if, if, if you want to do that.

Yeah, that would be great. I didn't really know what a peat bog was, and I think we should differentiate between the United States and, or I guess North America would probably be better and, and Europe and Asia. What, what, what is a peat bog? And what is the condition of the peat bogs across, I guess, globally would be the question.

Yeah, so peatlands or peat bogs are, are really, it's a type of wetland. So if you think about wetlands, but peatlands are special in that as plants die and start to decay, that the, the organic matter accumulates faster than it breaks down. So you get a buildup of this organic layer beneath the, the wetland or the peatland and that it's, it's a, it's a layer of peat then. So that's what characterizes a peatland. Now, one of the important characteristics of a peatland is that water will saturate it up to about near the surface, at surface or near the surface. As you can imagine, that type of land would not be conducive to building roads or houses or farms or anything else. So the first thing you have to do when you use that land is you have to drain it. So you drain the water off of it and then that peatland becomes degraded. Now, in the history of, you know, humanity, you can look at the history of Europe, they've been using those peatlands for farmland and other reasons for a lot longer than we have been in North America. And what that has resulted in is over half of the peatlands in Europe are now degraded. And a degraded peatland will tend to give off CO2 instead of sequestering CO2 from the atmosphere. The situation's a lot different in North America, where we've just had fewer people. And most of these peatlands in North America are in Canada at, you know, very high latitudes. So where there's not a lot of people living to begin with. So the peatlands in North America are in just in much better health. And so that's one of the things that we discuss. But, yeah, so a healthy, functioning peatland will have water at or near the surface, and it's constantly sequestering CO2 from the atmosphere. That's what makes them so valuable globally. They're removing CO2 from the atmosphere instead of giving CO2 off.

So when I try to visually picture peat land, because peat is primarily just a bunch of organic matter that's broken down and become this sort of stable substrate that we know as peat moss. I would assume these lands are quite rich with plant matter in order for there to be plant matter to be broken down to create the peat. Is that accurate? Like, are there grasses and shrubs and things like that on the land, or are they fairly barren looking?

Well, when you talk about peatlands, there are two major types, and one is called a fen. You've probably heard that word probably before, just casually. But a fen is kind of an early development peatland, and they're dominated by sedges and grasses over time, and as the characteristics of that peatland change, and basically they start to swell up above the water table, they become a bog. And a bog is typically dominated by sphagnum mosses. So you'll see shrubs and some other plants and even maybe some trees growing in a peatland or a peat bog, but they're dominated by the sphagnum mosses, which is where, you know, as those mosses grow and then decay beneath. That's where we get this coveted sphagnum peat moss from Canada. So, yeah, that's true. If, I guess, if you think, and I have some pictures on here that you can show maybe, you know, in, in the, in the podcast. But I, I always envisioned them as being kind of like those images you see of the tundra, but there is a little more variety of plant life when you. In person, especially the ones that I visited in Ontario. Again, more shrubs, more trees than you might expect, but they are dominating stagnant mosses.

Okay, that makes, that makes a lot of sense to me, and that's great. You got to visit them. So what were your initial thoughts when you actually visited and saw them in person? What, what were the differences between what you had pictured in your head and what you were actually seeing?

Well, I guess one of the things that struck me, we visited a. What they would call a pristine bog. Never been touched or never been altered in any way. And we visited a rehabilitated or restored peat bog post extraction. So they extracted from this for 10, 20, 30 years, I'm not sure how long, and then they restored it. You couldn't tell the difference. My eyes couldn't tell the difference. And maybe a biologist would come in and they see they're looking for certain plant species or something. But, you know, to me, visually, they look very similar. So I was really struck by that. The, you know, it's really strange when you walk on these peat bogs, you know, just how, I guess not a scientific term, but how squishy they are. I mean, you really sink down in them. So, so they're beautiful. They're, it's, you can, you know, put your hand down in there and pull up a big clump of peat. It's really, it's fascinating to see. Everyone should do that if they get the opportunity. But, you know, hearing about the restoration efforts and the success that they had in that, that just didn't. It's more of a conservation practice is what I observed than what, you know, some of the media would have. You think they're strip mining Canada and it's just not the case. The area that they're harvesting peat from is, is incredibly small and then they're restoring it afterwards anyhow. So it's just a different narrative than what you see in the media.

Yeah, let's throw some numbers at people here. And I'm, I'm looking at your, your slides here. And so on the, when you talk about pristine peat bogs, you mentioned that sphagnum mosses grow slowly about 20 to 120 millimeters per year and peat accumulates at about half to 1 millimeter per year. Just to give people some numbers there. What, what amount of peat is actually being harvested in North America right now relative to the, the vast size of these, geographically, of these, of peatlands?

So, and let me, let me pull up those numbers so I don't know, say something inaccurate here.

And, and while you're looking that up, I'll add one more fact here from, from your slide, is that peatlands cover about 3% of the Earth's land area, which I thought was really interesting. I wasn't aware of that. And it's a massive source of carbon sequestration, which is why this is such an important topic for people that are concerned about the environment. So.

Well, let me talk, let me get back to that point because that's really interesting too, because that gets to the heart of the problem. But to put this into perspective, every year, during a good year, they will harvest around 12 million cubic meters of peat to sell for horticulture out of Canada. Now, you can estimate this several different ways, but what I've estimated that the peat lands in Canada are accumulating about 600 million cubic meters of peat every year. So they're harvesting 12 and another 600 million cubic meters are being generated. That's because almost all of the peatland, well over 80% of the peatlands in Canada are still in a pristine condition. They're untouched, unfazed by human activities. So although they grow at A very small rate. There's such a massive land area that is growing peat that it's accumulating 50 to 100 times faster then it's being harvested for horticultural purposes in Canada. So it is, it's growing at a very rapid rate. Well, I say, let me take that back. It's not growing at a rapid rate. It's growing much more than it is being harvested.

The scale of it is so massive that we're accumulating it faster. So that's, that's really fascinating to me because that is something that you hear the opposite a lot is that we're, we're harvesting peat way faster than it's accumulating. And so we're demolishing, you know, these beautiful Canadian bogs. So that, I think that's an important point. I just want to highlight that you.

That you say there, yeah, and you know, like I said, the, the image they paint is that we're strip mining Canada. And that's just not the case. The area that's being harvested is really small. And now over the, let's say they remove a layer of about 1 meter. Okay. Over the life of that bog, it may take 10 or 15 years to do that. But let's say they remove a layer of 1 meter deep. Now because it only grows about a half a millimeter to a millimeter a year, if you wanted to replace that meter, it would take like a thousand years. So that's the argument soft, often thrown out. We're harvesting peat from these bogs and it's going to take centuries for it to be replaced. But the truth is once they're done harvesting, they will what amounts to reseeding it with sphagnum. It's a fairly involved process to restore those peat bogs. But once they're done, those peat bogs become carbon accumulating carbon, sequestering fully functioning bogs again. So they start accumulating carbon and peat almost immediately. Within several years, it can take three to maybe 10 or 15 years, depending on the, you know, rainfall and things like that. But well, short of that 1000 year window that people like to convince you that it's going to take to rest, they become functioning peat bogs again relatively quickly.

Okay, that makes sense. So essentially what you're saying is this idea that once a bog has been harvested, yes, it will take hundreds if not thousands of years for that bug to get back to the level of, of peat moss that it had. However, it, that during that time it's still going to be sequestering carbon. And because it's such a small overall percentage of peatlands that we own that we have, we're still growing more peat than we're harvesting. Yeah, considerably more.

Massively more. Pete in Canada is it is accumulating way faster than horticulture is using it by. Again, one to two orders of magnitude faster.

Okay, and let's touch on that. So the peat moss, sphagnum peat moss coming out of Canada is primarily used.90% of it, according to your slide, goes to the United States, and it's all used for horticulture. However, this is not the case in Europe. So Europe is a very different situation than North America when it comes to the uses for peat. Can you touch on that a little bit?

Yeah. Now, one thing Europe does have in common, all of the peat harvested in Europe, 96% of it stays in Europe. So that's one of the first things that drew me to this discussion. Europe has a much longer history than we have here in North America. And I can touch on that a little bit too, in terms of population. But, you know, the peatlands in Europe are in very bad condition. The peatlands in North America are in relatively very good condition. So what we do in North America, for growers, I mean, we're using, you know, the peat from Canada. It should be based on the conditions here in North America. Let Europe handle their problems. The peat we use in North America comes from North America. The peat used in Europe comes from Europe. But now, getting back to Europe, right now, 62% of the peat that they harvest there is used for energy. That's something that has never been done in North America. They have never used Canadian peat to generate fuel or to, you know, heat homes, but most of it is used for that purpose in Europe. 38% of the peat, they call it in this paper, you know, it's been cited there, 38% is what they call non energy uses. But that's all horticulture, when you read between the lines, all of that. So it's either energy or horticulture in Europe, but that's not the case in North America, where we're harvesting it just for horticulture in this continent.

And I would assume combustion of Pete has further carbon consequences, would be my assumption.

We look at the carbon footprint of peat used from horticulture, we assume that all of it is mineralized or decomposed at some point. So, and that's one important point. When I give you the numbers for the carbon footprint of peat, that's assuming all of it's converted into, all that is harvested is converted into CO2. So you would get the same result by burning it, you know, so. But even that said, when you look at the numbers for the carbon footprint of peat is relatively small compared to other human activities and even other substrates.

That's interesting because when I think of peat used in horticulture, I assume that there's an ecological cost to the harvesting, which there is. But then once I as a consumer receive that plant or soil, that plant that's planted in, in the peat moss that I'm planting into my yard, I see, I look at it more as a redistribution of peat moss into, you know, my local native soil or some other. I mean, I realize there are people that are using this media and then it's ending up in, in landfills and things, which is unfortunate. But that to me has I guess a different ecological or environmental impact than combustion.

I agree. No, you're, you're right. That's 100% correct. However, when they calculate the carbon footprint, you may not see this, but that peat within 100 years is going to decompose probably completely in your yard. If you plant, you know, azalea in your garden, the peat moss is going to be gone within 100 years. So they're assuming all that has been converted to CO2. So when you look at the carbon footprint for peat, that's a worst case scenario. And it's probably, as you say, much better because you're using it to grow plants, maybe using a, grow four seedlings that turn into 80 foot tall, you know, spruce trees in, on, on the side of Mount Hood, who knows? But the, the, the carbon footprint, the way they calculate it, is a worst case scenario and most of it comes from the actual carbon stored in the peak.

Okay, so what, what were your findings in regards to the, the studies and research on peat and other substrates and their carbon impacts?

Well, one thing I'd like to bring up first before we get into that is just the, the, the global climate situation. Now what really, why this is such a concern to so many people is that if you look on planet Earth and this in that slide deck I showed you, this is on slide 12 right now there are about 885 gigatons of CO2 stored in the atmosphere. And a gigaton is just simply a billion metric tons. So 885 billion metric tons of CO2 or CO2 equivalents in the atmosphere. Soils around the globe contain about 1,700Gigatons of that 550 to 600Gigatons are stored in peat. Now the problem is, and the concern is, what if we continue to degrade peatlands, if we continue to lose that carbon into the atmosphere, what if even half or, or a quarter of that 550 to 600 gigatons is released into the atmosphere to join the 885 gigatons already there? Well, that would be an ecological disaster. So that is why there's such a push to maintain the CO2 sequestering functions of peatlands around the globe. And that's the concern. Now, if you go to the next slide, this shows how the change in CO2 levels caused by human activities around the globe and basically our Biome, forest, grasslands, etc. Can absorb about 6.6 gigatons every year. The ocean or about 2.8 gigatons. So planet Earth under natural processes and is absorbing around 9 or 10 gigatons of CO2 from the atmosphere every year. The problem is humans are giving off about 60 gigatons. Now 20 gigatons comes from energy production, burning coal, burning fossil fuels, whatever. 14 gigatons comes from industry. There's this term called folu, or a folu. I don't know how you would, you know, sound that out, but it stands for agriculture, forestry and other land uses. That's given off 13 gigatons. So that's basically farming right. Now in that number, there's the Canadian peat industry that is responsible for generating 0.0009 gigatons. So when you look at the global scorecard, it's a very small fraction coming from peat. But the concern is, you know, maintaining the quality of peatlands around the globe. But can we use peat from Canada for horticultural purposes? And, you know, look, based on this data, the carbon footprint on an annual basis of using horticultural peat is so small, it, it's not zero, but it is very small relative to other human activities.

Yeah, some sort of look at your slide, you're saying like 8.7 gigatons of carbon or CO2 is released through transportation.

Yeah. And then airplane cars. Yeah.

But yet Canadian peat is 0.0009 gigatons. So it's substantially less. I mean, this is a pretty terrifying slide when you think about it in terms of the amount of sequestration we're having relative to the amount of release. But in, in terms of Canadian. Pete, it's, you're, you're saying it's, it's.

It'S rather negligible or small negligible relative to other activities. And you know, we should always strive for zero. But again, you know, we're growing plants, we're using this Pete. We're not burning it for fuel. We're not, you know, powering luxury yachts. We're growing food, we're growing, you know, four seedlings and we're growing plants. So it's.

So it has further sequestration properties as it adds to our overall quote, unquote biome as it's used in this, in this image.

That's absolutely right. And one of the things I talk about at the end of my talk is that the only tool we have right now, the only reasonable tool we have for reversing CO2 levels in the atmosphere is reforestation of land that is currently not forested in the United States and around the globe. And the only reasonable way to do that is to drastically ramp up our reforestation. Nurseries, our four seedling nurseries and now studies by the four seedling industry has said the best way to do that is use container grown for seedlings that use peat. So an irony of ironies, it is the one material that may help us get out of this mess.

That is interesting. So before we move on, can you just touch on Europe again? Because you mentioned that, you know, a lot of it's used for energy that it has, they have all these issues. Is there, I mean, in your opinion, is there a solution for folks in Europe in terms of other options or is the conversation around Pete quite different? Like if you lived in London, would you use peat moss versus if you lived in North America?

Well, I believe in Europe there is much greater scrutiny now they've banned all harvests of Pete from Ireland. So I, you know, they had to shut down peat harvesting completely. And, and now what has happened though is they're just getting their peat from somewhere else, like Latvia or Estonia. So they haven't stopped the use of peat, they just shifted where it comes from. So Ireland's taking care of Ireland, but they're still using peat, I guess, is that now they have been very proactive in using wood fibers and other alternative growing media, but again, comes with its own set of problems. So, you know, and when I talk to some of my European colleagues, what is actually legislated, what is proposed, what is actually being done in Europe? It's, it's a real mixed bag and it's really hard to be, you know, give a concise overview. But there is more pressure for environmental legislation there, there is more pressure against using it just socially. So I think they want to phase it out completely. Completely from England by the year 2030. So. But keeping track of what is proposed versus what is actually done has been somewhat challenging, you know, from this side of the pond.

Well, this might be a good time to transition into other substrates and how they compare. So one of the things that you did in your presentation was you look, you know, we've been talking about sort of the environmental impacts of peat moss as a substrate, but if we want to make a determination, a true determination about a substrate, we need to also look at its social and human health impacts as well.

That's correct, yeah.

Which I think is a really important aspect, especially when we start talking about things that are being transported over large distances to get to us. So, yeah, let's dive into it. So can we kind of COVID peat moss first from sort of this, I think you call it a life cycle analysis in terms of human health effects, social effects, environmental, and then we can do the same with some of these other substrates.

Yeah. So now some of your listeners probably have heard about this before, but there are, there's, there's a, there's a process called a life cycle analysis or life cycle assessment where they try to quantitatively measure the impacts of any service, any process or any product on, you know, the environment, human health, society. And, and, you know, they're constantly expanding what they can measure the impact on. But the, the goal of these is to do a fair and objective quantitative analysis to determine how these, how these products impact, again, society and the environment. So when we look at peat, we can measure the big one is the carbon footprint. How many kilograms of CO2 per cubic meter of peat is released in the atmosphere when you harvest that peat and use it for horticulture. So they've done that. And those values range from 20 to 150 kg of CO2 equivalent per cubic meter. Now, what is, you know, you can look at different studies. Each study makes a different set of assumptions. Where was that peat harvested, how far was it transported and then how was it used? So based on those assumptions, they will come up with slightly different values. But generally speaking, most of the values range from about 20 to 50 kg of CO2 per cubic meter. One of them was as high as 150. So there's some variability there. But now, as we discussed before we got on here, a lot of this data comes from Europe. So we only have one study to my knowledge, that was done in North America, and I think they term determined that the carbon footprint was about 50 kilograms per cubic meter. So now you compare that to core just in terms of its CO2 equivalence or its carbon footprint. In most studies, but not all. In most studies, core has a slightly lower carbon footprint than does peat. But now the carbon footprint's only one part of the story. You can look at the environmental impact that also considers things like terrestrial acidification, fresh and marine water eutrophication, ecotoxicity, land use, fossil resource scarcity, and water consumption. When you factor all those in, core becomes. It has a higher relative impact than peat, usually much worse. And a lot of that has to do with how coir is processed. It uses a tremendous amount of water, and it also releases a high salt load into the environment wherever it's done, in order to, you know, flush the salts from the core pit. So, yeah, when you look at the. The total environmental impact, generally, peat has a much lower impact than does core or other products like Rockwool and Perlite.

Yeah, when I first started looking into this, I was trying to put together an article comparing peat versus cocoa, because it was something that I was interested in. And one of the things that I found was with Coco Coir, like you mentioned, there's a. There's a huge water consumption and water is at a premium these days. Clean water is something that we struggle with globally. So we're using a lot of water to flush all the salinity. Like you mentioned, that salt has to go somewhere, and then that clean core has to be dried and compressed and shipped all the way over here to North America because it's being harvested in tropical areas. And then the other thing that surprised me too, that we haven't talked about, that falls under sort of the social, human health aspect is the respiratory effects that this was having. It may have been generating economic wealth for a particular community, but it was causing huge respiratory problems for the workers that were collecting the core. And I don't know if that has changed since I first looked into this 15 or so years ago, but that was something that I. I thought was a considerable point to consider when making a substrate decision too.

Yeah, you're absolutely right. Now, all the core today, most of it comes from Sri Lanka or India, although they are trying to develop some products from South America as well now, you know, harvesting from South America. So we'll see how that goes. But you're right, you know, they can also measure human health impact that incur. That includes things like toxic effects, carcinogens, respiratory effects that you mentioned, ionizing radiation, fine particulate matter in ozone depletion. And when you factor those things in, again, in every study that we have data for both PETE and Core. Core has a higher human health impact than does Pete and Rockwool. In one case, Rockwool was actually lower than Core, but Rockwool is also pretty high. So, yeah, you're right. Now, one thing I will say is that I believe there's been a lot of investment in the core in the last 10 years. So some large companies from North America are investing in that, and I think they are. So, you know, you're right. When we first started using Core, there was lots of concerns about worker safety, worker conditions in some of these developing countries. But I think a lot of that has changed and I think, you know, corporate investment and those sorts of things has improved that situation, although I don't have firsthand knowledge of it. That's just what I suspect. But still, I mean, these studies were done in the last two or three years. The human health impact, of course, still greater than what peat is.

And along with this, I just would like to add, I'm making personally the assumption that Rockwool and Perlite are worse substrates than Peter Coco. So I'm kind of ranking them in terms of environmental impact as from lowest to highest going, sort of Pete Cocoa and then I would assume Perlite, then Rockwool. Yeah, as the major substrates.

You know, Rockwool is something that's used, of course, by hydroponic growers and that's kind of almost a whole different category. You either use it completely or not at all. But Perlite, something that we've always traditionally mixed in with our substrates, especially Pete, and I think everyone in the industry, from grower up to substrate providers, manufacturers, everyone, you know, that that's, that's the first thing that people are looking to replace. That's kind of, you know, people are looking to get away from Perlite. And now I get a nasty email from the Perlite manufacturers every time I say that. But that, that's just, you know, the reality.

Yeah, that's a tough one because.

I.

Mean, Perlite works so well. Now we use pumice in our soil mixes because it's, it's heavier, which is great from a substrate perspective, but in terms of shipping and, and those sorts of things and fossil fuel cost, it's, it's definitely higher to move pumice around. One of the things that's so awful about the cannabis industry, which I'm a part of, is that a lot of people are throwing out this media. So whether, you know, at least with Rockwell, people are now starting to reuse it and things. But the Amount of, of perlite, the amount of coco coir and peat moss that gets put into landfills or dumped out every round is really quite a contributor, I think to environmental damage. One of the things. And you, you don't know me, you know, we haven't talked about this. One of the things that my company does is we work with folks in creating like for example, taking the cannabis, putting it into a soil bed, like let's just say a four by four bed of soil. And then at the end of the cycle we will soil test and reuse that media. So we're just adding, you know, nutrients back into it, treating it sort of more like agricultural land. So while we do have the environmental impact of, of starting with peat moss, we're not adding more media every cycle. We're reusing that substrate over and over again. And we have people that have been doing this for, you know, five to 10 years now with the same, the same media. And so that to me feels better at least in when I'm using peat, at least I feel like I'm creating a highest use case for it from a horticultural perspective to where I'm having less environmental impact once that soil is sort of created and in place.

Yeah, that's right, yeah. And there are lots of creative ways that you can reuse Pete. And you know, I think it's, it's an especially post production, it's an excellent soil amendment if you have that outlet nearby where you can apply it to agricultural land. You know, whereas I know using some of the mineral products like Rockwool or perlite disposal is a problem. It's a challenge. Now, you know, you mentioned pumice. I was a professor at Oregon State University for a while. So yeah, we work with pumice a lot. That's an interesting material to work with and a very good substrate. And can you share a little bit.

About pumice since it sounds like you have some experience with it in comparison to perlite and other options?

You know, I, I guess in the Oregon nursery industry it was used. Now this is outdoor nursery crops, woody plants, you know, container nurseries. It was used almost exclusively relative to perlite. We didn't use perlite in nursery crops. We used Douglas fir bark and pumice. And so I went and visited. There were at the time there were two sources of pumice in Oregon. One from the Bend area and one down south, southern Oregon. I forget the exact region, but just visiting those, you know, those pumice area, the pumice mines and seeing how they, they Mine it from the ground. And then looking at some of the chemical and physical characteristics of the pumice and how it's used in, in, in nursery crops. And I wrote some articles years and years and years ago. I don't remember the details anymore, but. And we use it like 10 to 20% of the growing of the container mix. So it was relatively minor component in the substrate. But yeah, it was interesting looking at it, especially visiting the mines and seeing how it's extracted and, you know, processed and that sort of thing.

And what are the differences between perlite and pumice for people that are unfamiliar?

Well, I would say the primary difference you mentioned is the weight. The, the, the, the pumice is just heavier and, and almost, if you're not, to the untrained eye, it might even look the same, feel the same. It's, you know, it's a porous volcanic material. And the pumice out of Bend was very white, and so you might almost be tricked into thinking it was perlite. The pumice out of southern Oregon had a, it was stained, it was the, the ribbon of pumice they were mining was closer to the soil surface, so it was stained a little more yellow and it didn't look as bright, gleaming white as the Bend pumice did. But other than that, as far as growing media, other than it increased the bulb density of your media a little more relative to what you really didn't measure anything. There was no measurable difference in chemical properties or otherwise, at least from what we've done. It was just, you know, about the same particle size. Now the, the products that we use in nursery industry were a little dustier. They had a lot of fines in them. You know, the pumice product, unless you had it double screen, but otherwise it was very similar to perlite.

Yeah, we had to move to using two thirds medium, one third large pumice. For that reason. When we used just medium pumice, the amount of fines in there actually created less aeration ended up being this sort of goopy mess. So that is, that is a good point. One thing, as I think about other things that we can add to media for aeration, and I want to transition into pine bark next. But as I look for other options for aeration in my industry, people will use rice holes as a form of aeration, but that has sustainability issues. And it also is potentially a source of arsenic, which, because cannabis is being tested now for heavy metal content at very, very strict levels in some regulated states, that can be a huge Contributor and a big problem that also makes it hard to use things like lava, volcanic lava rock, because as that breaks down, if you're raising your media, that also could be adding heavy metals. Whereas the pumice that we've seen is, is pretty clean relative minerally. It doesn't, it doesn't really have a lot of heavy metals. So I just wanted to mention that as it's sort of an aside around, you know, aeration options there really, I haven't found a better one. But maybe, maybe exploration of, of pine bark or some of these other wood substrates is a possibility. I mean, what are your thoughts on them?

Yeah, so one thing is that I did research with biochars about 10 or 15 years ago, and problem was, at the time, it was an interesting product to work with, but there was no, there was no source, no large volume source of it. And as much as people talked about it and how exciting biochar was, you know, you really couldn't find it for a reasonable price. Well, that's changed now. I don't know what has changed in the energy sector, but now there are more sources, abundant sources of biochar commercially. So that's something that I know one of the major substrate manufacturers now are using biochar instead of perlite as the kind of the coarse, quote unquote aggregate that you put in the media to provide drainage. And so presumably biochar would be very stable for very long periods of time and, you know, not have some of the, you know, the heavy metal toxicities that you might find with other, you know, mineral sources from the ground. Wood fibers are something, you know, I think we discussed this a little bit before we got on the air. That's something that started in Europe and now you can find an abundant supply of that in North America as well. There's. There's at least one major manufacturer and there may be two or three coming online soon. But literally taking the wood portion of pine trees and, and I'm not sure the mechanical process they put it through, it's some sort of disc extrusion, I think, but it creates a fiber. It's almost like, you know, a wooden brillo pad is what it feels like. Very difficult to mix and very difficult to work with from a mixing standpoint. You need specialized equipment to do that. But if you have that equipment and you can mix, does create a fairly good substrate. And you can replace up to 30 to 40% of the peat or maybe use that as the aeration component of your media.

Yeah, I want to back up For a second. I'm really glad you brought up biochar. It's something that I sort of take for granted because it's something we've been using for a long time and I've done podcasts just on biochar because I think it's so fascinating. But yes, that is another great option. I haven't experimented with using it as more than 8% of my total media primarily because of cost. And again, when we talk about biochar, it's like compost. I just for listeners, keep in mind they're not all created equal. Particle size is going to have a big impact in terms of the gas exchange, moisture retention, aeration effects of biochar. So don't just go out and buy a bag of biochar and think that you're going to get these results. You need to do a little, little bit more research into it. But yeah, I think, I think biochar would be a great solution. It's still, I think the, I still find it prohibitively expensive to get quality biochar in a media at a high percentage. But you know, for a home grower that might be quite reasonable to consider experimenting with at higher ratios than the 8% that we go with.

Yeah. And what we have been working with was more of like a 15% on a volumetric basis. So we're probably closer to you in that regard. Yeah. And, and again, as a scientist, I, one of the last things I think about sometimes is the price, which maybe I should think about that more often because that's what the grower ultimately is going to be looking at. So I'm not sure what the cost on the material we've been working with has been, but it's a wood based biochar. You know, as when I work with these companies that do the pyrolysis that they're, they're primarily after the fuel and the, the biodiesel and the biogases and then they have this black stuff, this solid material at the end like, hey, what do I do with this? And you know, using it in a growing media is a, is a real obvious choice. But yeah, they need to get the price down a little more or at least not rely on growers to subsidize that fraction of it for them if they're going to be making money off the gas and the fuel from, you know, the pyrolysis. And, but that, that's usually, you know, how the conversation starts. There's a supply of it and then how do we get, how do we Use this, you know, sustainably and maybe make a little money from it.

Yeah, and I've seen. I've seen actually in Oregon, my father was actually working with some folks down there in terms of using kilns to, when they go out and do logging for the forest slash, to sequester the carbon from the forest slash and then create a byproduct, then could either be put back onto the land or potentially sold to offset some of the costs associated with setting up biochar kilns. So, yeah, biochar is something that I think is great and it is carbon positive in terms of sequestering carbon versus the carbon loss that we would normally see with the timber industry. So I think that's a really good one that you brought up. And we've done some trials ourselves, but there's actually a lot of research around biochar. But we've seen better growth, plant growth by using biochar, even as low as 5% of our media, which sort of surprised me in some ways. But yeah, I definitely think it's something that people should consider in their substrate. If we're having a substrate conversation like this, I'm. I didn't think to bring it up and I'm so glad you did.

Yeah. Well, and you know, you brought up an interesting point. And it's funny because I used to say the exact same thing. Biochar is a lot like compost. You got to consider what was the feedstock originally, because that will determine the chemical properties when, when you create the biochar, how was it processed? You know, just like how was it composted? You know, what was the pro. How was it pyrolysized? And then were they post treatment, you know, post pyrolysis treatments that were applied? But yeah, not all biochars are not created equally. They vary incredibly depending on what you started from and how it was pyro. Pyrolysized. So that's a very good point, considering it as you would compost. Not all are created equal.

Yeah. And people ask, you know, can I just go down to Home Depot and buy some charcoal, throw that in my soil. And a lot of times that's not pyrolysized to the extent that we want for biochar. And also it may contain heavy metals and other toxins, because they're not looking to create the same quality product that we may want for horticulture. At least is. Is my knowledge around it. I wanted to. Before, before you go, I did want to talk about these wood substrate alternatives. Because I think it's something that I've looked into and I personally have not had a lot of success with them in terms of creating the same level of plant health and plant growth. But I'm not going to attribute that to the media or the substrate. I'll just say that that's on me. I'd love to hear your thoughts around it. And one thing that I do want to bring up before I let you talk about it is the fact that on, on soil bags, the way the labeling works around these products is you may see them listed as forest byproducts, pine bark, pine bark fines, and a variety of other names. And like biochar or like compost, that could speak to anything from, you know, high quality pine bark finds that are going to have good results potentially in your mix to something like sawdust that's just maybe added as a filler. So it's very challenging as a grower to determine what you're getting in a bag without doing a little bit more digging. I guess the labeling doesn't give it all away.

Yeah, that's right. And you know, I, my guess is that the larger commercial substrate providers are going to do a better job at guaranteeing what comes in that bag than what you might find from like, say like a Home Depot or just going down to the garden center and products that are, and I know this from personal experience, products that are geared toward homeowners, they'll fill that bag with anything where the manufacturers, when they're selling it to a commercial grower that needs crop uniformity from not only within a crop but from year to year and you know, crop to crop, they're, they're much more conscious about what they're putting in and making sure it falls within certain quality standards. So, but that, that's my experience when you, when you're, when you're using a homeowner geared product, it's, it's, you never know what's in there. It's just the wild west is, you have no idea.

So when you say par. Pine bark finds, you kind of described that a little bit. Or bark fines. Can you talk a little bit about sort of the physical properties as well as what, what sort of percentages people are using them in and what sort of results we're seeing in horticulture right now?

So with pine bark and pine bark fines and that can mean a lot of different things. So you know, we would generally look at a particle size distribution of those, but you're never going to get the water holding capacity that you would find with peat. And no matter how fine you go with these pine bark fines, peat moss is just going to be a little better holding water and buffering water, the water buffering capacity. I also believe that the, you know, the cation exchange capacity and the pH buffering in peat is a little better than it would be in pine bark fines. Generally speaking, you could use 100 pine bark to grow an outdoor nursery crop. What kind of our ideal substrate in Ohio would be something like 80% pine bark, 20% sphagnum peat. That will grow a really good crop. Now, of course, then you have to add, you know, a little bit of lime and fertilizers and everything else in that. But in terms of the physical components of the media, that's a great crop for, for an outdoor woody plant. Now, when you go into more herbaceous things, smaller plants, the smaller the plant, the more sensitive it's going to be to, to the chemical and physical properties of the growing media. So that's where peat moss generally does a lot better than pine barkwood. But large, robust, woody plants, we have a saying you can put 20% of anything in those pots and it's going to grow just the same. Now, they're all that, but they're just more robust to less ideal, you know, substrates than a small floriculture crop or perhaps, you know, cannabis plants in maybe a one or two gallon pot. So that, that's my experience with pine bark and pine bark vines, makes for an excellent growing media, the primary component used for nursery crops. But when you start growing, you know, again, more herbaceous or smaller plants, you have to be a little more selective and careful with what you're, you know, using.

One other thing that we haven't really talked about that I just want to bring up too, is sort of the. Because when I think about a substrate, and I've mentioned this on the podcast, a lot of times, I'm looking at a substrate from about essentially like three different pillars. Like, I want to look at the physical properties of that substrate, the chemical properties. So like, where's the ph? What sort of minerals is contained? And then lastly the biological properties of that substrate. And we haven't talked about biology at all. And one thing with peat moss, and I can say this just from looking down a microscope, is it's biologically active, it contains good biology. Whereas some of these other substrates, like coco coir or pine bark fines that would have to be introduced, it's not going to come in with any sort of nutrient cycling on Organic side in terms of the, the biology in that substrate. Do you want to touch on that at all?

Yeah, that's actually something we've been working on a lot for the last five to 10 years now. Going back since we started using growing media in the 1960s, studying the biology has been incredibly difficult because you're limited to studying maybe one or two pathogens or say beneficial organisms like mycorrhizae, one or two things at a time. And only things that you can plate in a petri dish, other organ are just too difficult to quantify or anything else. Now with the advent of DNA technologies, say 15 or 20 years ago, and around 10 or 15 years ago, they became very affordable in an agricultural research sense. So now using DNA sequencing technology, we're just starting to look at the microbiome in growing media. You can find several papers out there. Now what I would say is the, the, the microbiome depends on what you start with. And on day zero, they're going to be very different in containers filled with different media or even compost. But after two or three months in that growing media, under those conditions, with the irrigation, the fertility, the temperature, all the environmental conditions that you have, that's going to select for certain consortia of, you know, a microbial community. And no matter what you started with, a lot of that's going to die out because it just can't survive in that environment. What we find is if we start with different media of different compost or different, you know, components, they tend to look the same after about three months in the same. So it's kind of like I tell people, if you want to increase the biodiversity of the North Pole and you took a bunch of tigers, lions and zebras up there, after about a week you'd have a bunch of dead lions, tigers and zebras. So it's not so much what you put into that media, it's what, what will the environmental factors sustain in terms of, you know, microbial organisms growing? One of my colleagues here at Ohio State University, she did something really clever. She was looking for beneficial bacteria and she collected her sources from a commercial greenhouse. So those bacteria, if she found, you know, plant growth promoting properties within those bacteria, they are more likely to survive if you then apply them to other containers. And that, that program is actually working quite well. But it's a, it's, it's something, there's a lot of snake oil out there. A lot of growers will like to buy things because they think it's biologically active. And what do you what does that even mean in, in a realistic sense? It's whatever that company wants it to mean that they're, that they're trying to sell the product to. So we're just starting to learn now about what actually lives in these container media and, and you know, what you, what will survive in a growing media versus what you apply to that media. So it's, it is very, a very young science. We know a lot less about that than we know about the physical and the chemical properties. Just because it's so hard to measure and even now it's still really expensive, you just can't go out and it's actually, it's really difficult to do. It's, it's, you know, measuring pH and EC or porosity. Those things are relatively straightforward and simple. You know, getting a good microbial community analysis of a growing media takes a dedicated person who knows what they're doing and it's somewhat difficult.

So. Well, I think that's really interesting about what you said regarding various substrates containing similar biological communities after a given period of time just being in the same environment. That's really interesting. One thing, so to summarize sort of your opinion on, on microbes or biology, it's that it's an, it's a side of the industry that we're still learning a lot about. It's, it's expensive and maybe not the best tool for making diagnostic or dis, you know, data driven decisions about our cultivation habits.

That's. Yeah, you're exactly right. And what, what I, what I know about it is only the tip of the iceberg. I mean, we know so little about those biological communities. Even if you looked at all the papers that have been published to this day, it's just a small amount of information and we just, we know less than what we know. I mean, we have a lot to learn about that before we can make any really conclusive decisions or you know, give it conclusive advice on what you should or should not do. All I'm talking about is based on the scantest amount of information what I've observed on some of the studies that we have done on how these communities start out and how they change over time. But again, we have not done nearly enough research on this to speak authoritatively and we just don't know enough to, to really say one way or the other.

Yeah, I went to a talk by a soul scientist at a college, oh, 10, 15 years ago now, and one of the things he said that really stuck with me was he said we know more about the surface of the moon and the depths of our ocean than we do with what's going on directly underneath our feet. We just don't understand that biology and it's so complex. And I also got to attend at the International Soil Science Society of America conference one year. It's a mouthful. Was a speaker that did research doing DNA analysis on agricultural lands in relation to hydrology. And so basically they measured, they looked at all of what was in a soil, a soil when, when the soil was dry and then they came back after a rain and measured it and then maybe after a watering event and then again let it dry out. And you saw a massive change in fungal to bacteria ratios. You saw a huge change in the consortium microbes that were present. It's such a complex community and yet I see people making decisions about their cultivation habits based off of what they see under a microscope. And I'm literally looking at my microscope over here because it's something that I like to do. But I use a chemical analysis, a soil test because like you said, we have very reliable metrics around eclipse ph, you know, the levels of calcium and magnesium and potassium that we know a particular crop needs. And so to me those are more data driven variables than the microbiome, even though it is quite important.

Yeah, you're absolutely right that you just nailed it. That's exactly, that's exactly my assessment of it now and again. We just spent five years doing studies on the microbiome and we just know so little that it's really hard to make, you know, yet like you said, data driven decisions based on, you know, what we, what we do know.

Yeah, I mean we do know that compost is this magical tool that we have in our arsenal that we can add into soils and see these. Because it is such a concentration of microbes that we see such great results from it when used properly. But in terms of identifying the microbes and I think that is a challenge. But I look forward to what, you know, what research is coming out of your university and others on this topic.

Yeah. And it's going to be slow, I fear, just because of the expense of it. But it is, it's, it's really, to me, it's the last frontier. You know, we have. We're really good at the chemical and physical properties, but we need to be better at measuring and understanding how to. Well, first of all how to measure then how to manage the biological properties. Because I think that's what growers are really looking to do. They understand the importance of the biological component, but we just don't know enough to know how to manipulate it or how to use it to our advantage. Great.

So there were two substrates that I wanted to ask you about that we didn't talk about. I'm kind of throwing you a curveball here too. Have you heard of pit moss by chance? It's a newspaper cardboard based substrate. I've, I've talked to the owner. We actually did some trials with it. I personally wasn't able to create a chemical analysis, soil test that I felt really comfortable in utilizing. But I think it's a really fascinating recycled product in terms of, you know, utilizing a waste stream into a potential substrate.

It's a great story, but I have not seen evidence yet that it's going to make an effect effective commercial substrate. I, I would just say, you know, do your homework before you commit to doing anything with that product, whether you or, or one of your audience members. You know, do your homework and make sure it works well in your production system because there could be some challenges. Okay.

And Dairy Wash is the other one that I see at trade shows that is another waste product that when I hold it in my hands and look at, seems like it would be a very viable substrate. It feels like it would grow plants. But I, but with a high ph and some of the other challenges around it, I haven't, it's another one that I haven't really had good success with. Have you done any trials or seen any research on that as another option?

I have seen some of these dairy digestates and things like that and they look just like Pete Moss. And they feel, they, they look and feel right. But again, you know, and I've seen several of these companies come and go and their products come and go and none of them have been successful. None of them? None of them. I should say not the companies. But I have not been able to use those products successfully in, you know, to, to grow plants. Well, now maybe that's because I'm a bad horticulturist, but you know, that's how.

I feel about myself with those two. So that makes me feel a little bit better.

But I would tell any of your listeners, you know, you know, always try new things but you know, do your homework and, and really vet them before you, you know, consider going, you know, all in on it. Because I, you know, I've seen a lot of challenging, They've not worked too well for most people that I, you know, the examples.

Okay, so just to summarize sort of our conversation today, Peat Moss does have an ecological impact, an environmental impact. It may not be quite as extreme as some of these. The, the media stories are telling us. And all of these other substrate options like Coco, Coir, Rockwool, Perlite, all have an ecological impact as well. Biochar is something that could absolutely be considered, but check your, you know, check your quality, do a little research before incorporating it. And then some of these other alternatives like the dairy wash, pine bark and pit moss, all have challenges as well, but maybe could be incorporated in at smaller percentages than, say, just completely switching over as a media, maybe use it 10 or 20%. Um, but as of right now, there is nothing from a plant perspective in regards to substrates that's going to beat peat moss.

That's correct. And one thing that I tell growers too is this. We've been using peat moss for 60 years. And since that time, we have, as we discussed earlier, we have engineered the right particle size. You know, we buffer the ph, we, we amend it with starter charges, we have, you know, wedding agents, all that. And we, we're very good at using peat moss. What if we put 60 years of that same rigor and research into using Core? Would it be as good? Because Core is the only product, in my opinion, that can be used in the broad spectrum, you know, and all this, it could replace peat in many of the situations where you use pete. Now, there are challenges again, as you mentioned, with the ph and the salinity sometimes and the quality. But if we put the same amount of research in the core, could it be as good as pete? That's, you know, so what can replace Pete? That, that's my only, in my opinion, that's the only thing I know of right now. There's some things that need to be figured out, but that, that's what I would tell growers is it has, it has the potential. But we just, we put so much effort into refining the use, refining sagging peat moss, it's going to be really hard to just start using something or find something else and say, hey, let's try this, and it's going to work as well as Pete does. We just, we've engineered that so thoroughly. Well, it's a really great substrate. Foreign.

That was Dr. James Altland and you are listening to the Cannabis Cultivation and Science Podcast. Don't forget to check out the podcast page at www.kisorganics.com. just click on the Learn tab, then podcast. And if you want access to podcasts, as soon as they are recorded along with additional content and video video. We do have a Patreon account. We also do book clubs, hangouts and have a private discord channel for members. The KISS Organics website also offers a variety of soil amendments, lighting fixtures, beneficial insects and the highest quality commercial soils on the market. We carefully research all the products we offer and manufacture to make sure they are science based and meet our standard of quality. Thanks for listening.

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