Ep. 149 All About Mulch: Lay it on thick and keep it chunky | #GoodGrowing
Welcome to the Good Growing podcast. I am Chris Enroth, horticulture educator with University of Illinois Extension coming at you from Macomb, Illinois, and we have got a great show for you today. We are gonna talk all about mulch. This is a barn burner, ladies and gentlemen. This is gonna be the most exciting topic since you talked about grass.
Chris Enroth:This is gonna be a fun show, though. You know, I'm not gonna do this all by myself. I'm joined as always every single week by horticulture educator Ken Johnson in Jacksonville. Hey, Ken.
Ken Johnson:Hello, Chris. I like mulch more than I like turf grass. So
Chris Enroth:I I agree. What
Ken Johnson:it's worth. Yes.
Chris Enroth:And this is gonna be a a a an entire episode about mulch, And so hold on to your hats.
Ken Johnson:We're still just scratching the surface.
Chris Enroth:I know we are. And I I I just I don't know what to think of this right now. If I look back at my younger self and I said to my younger self, hey. You know, when you're a grown up, you're gonna you're gonna be like a quasi expert in mulch. My younger self would probably punch me in the face.
Chris Enroth:So your self would
Ken Johnson:say, what's mulch?
Chris Enroth:Yeah. Exactly. Like, who? Who are you? Am I really gonna grow up into this person?
Chris Enroth:Yeah. So I wouldn't recognize myself. I was in a I was in a punk rock band in high school, so this now I'm talking about mulch. So this is gonna be fun. And we, of course, to join in on on all the fun and festivities, we have a special guest today, horticulture educator, Emily Swihart the Quad Cities.
Chris Enroth:Emily, welcome to the show.
Emily Swihart:Hi, guys. Good to be back.
Chris Enroth:Well, we are happy to have you here to talk about everyone's favorite topic of mulch. I maybe I'm just having a midlife crisis here, so I apologize. But we're we'll get through this together that that we're all experts in mulch. Because we all actually spent a day and a half learning about mulch.
Emily Swihart:It was a great day. I don't know what you two are talking about. Like, I think our younger selves would be so dang proud of us and our knowledge of mulch. Maybe.
Chris Enroth:Maybe they would be. Maybe they're like, so they actually pay you to do that? Like, yeah. They do. Like, okay.
Chris Enroth:So maybe they would be proud. Thank you for shining that light on us, Emily. Because I I I mean, mulch is important, and that's why we're talking about it today. Mulch. Mulch.
Emily Swihart:We're gonna say that word a lot.
Chris Enroth:Yes. Yes. Alright. Well, Ken, if you wouldn't mind, just get this kicked off on the topic of mulch, this week with the first question about mulch, please.
Ken Johnson:Alright. Our first mulch question this week is, what is mulch, and what is it good for?
Emily Swihart:Ken, what a good question. Okay. So I'll start with the most basic definition of mulch being that it is a material laid on top of the soil rather than being worked into the soil. It can be any sort of material. There's wood mulch, course, and that I think we'll talk quite a bit about.
Emily Swihart:It's very popular, very available. Other mulches would include things like stone, cardboard, straw, leaf matter, all sorts of different materials just laid on top of the soil. You ask, what is it good for? A lot. It's good for a lot.
Emily Swihart:And before we get into that, I think I've warned you guys before that I like to consider the origin of the plants and the things that we're talking about when it comes to the natural world because these are not new phenomenons for the most part and neither is mulch. Most of the woody plants in our landscape, most of the perennial plants in our landscape evolved in situations or in ecosystems that had a natural mulching system built into it. So let's think of, like, a woodland setting. Nobody was going through and raking up leaves and removing them from the site. Every fall, you know, leaf debris, wood, materials that would drop from the under canopy or things that had died on the forest floor would just lay there and decompose.
Emily Swihart:While they were decomposing, they were suppressing some growth from other plants. They were helping to preserve some moisture in the soil, helping to protect soil from erosion. And so the mulch that we're putting on our landscape is doing kind of the same thing. We're trying to mimic some of those conditions in our own landscape with the material that we're putting on top of the soil.
Chris Enroth:And so we have a wide diversity of mulches as you mentioned, Emily. And so I'm curious. We'll we'll get into all the different types, but do you have a favorite that you typically would utilize in your home landscape?
Emily Swihart:Well, yes. I pretty much only use a, like, a wood mulch or a chipped kinda chipped wood mulch material for a couple of reasons. Probably economics is the first It's very available. It's locally sourced. I can get it from one of the local city compost facilities for a really good price, and it can go really long ways.
Emily Swihart:But I do that also because, like, a natural wood if it's it's material that has been, like, harvested from a tree that's either been removed or limbs that have been pruned off, a lot of times, it's more than just a singular material in that mulch. So you have components of heartwood. So that hardwood material that's gonna take a long time to decompose is full of lignin, and it just, like, kinda sits on your landscape for a longer period of time. Then you've got bark material, which is a little more porous. It can help with water retention.
Emily Swihart:Then there's also, like, leaf matter in there that's gonna decompose much more quickly and release nutrients and make those available to the plants that I am mulching. And so, personally, I just always use kind of a wood chip, wood mulch compound type of material. Do you guys use anything or have a favorite?
Ken Johnson:Yeah. I use the wood chips as well. Last couple of years, we're using more and more leaf shredded leaves and stuff. So in the fall, when everybody breaks up their leaves into bags and puts them on the curb, we drive around town and build a van up, make several summer runs, and but they're basically just store them in the backyard. We we got chipper shredders.
Ken Johnson:We shred them and either put them out or storm in bags in the garage. And last year, we didn't get to shred all of them before it started raining, got cold and everything. So we've only had 30 bags of leaves that sat outside during the winter and to kinda shred this spring. Some of them water got into the bags, and it was nice and anaerobic in there. But it
Chris Enroth:smells great.
Ken Johnson:Those those just got used as as is. From I don't like, like, non shredded leaves, like, they matte real easily, and that kind of sheds water and stuff. But it was good for areas we wanted to kill off. So, yeah, we're I like I like wood chips where we're doing more leaves just because it's easier to get ahold of in the fall.
Chris Enroth:Yeah. I I utilize both of those. I I like using the, the arborist wood chips. As you said, Emily, those leaves that get mixed mixed in sometimes when, like, a tree care company is cutting down maybe a live tree, some people don't like that. I do.
Chris Enroth:I'm like, it's free nitrogen. I will take it. And so I I I really do enjoy utilizing the arborist wood chips. A lot of times, if you can get ahold of a tree care company while they're working in your neighborhood, they'll dump them into your driveway for free. So that's what I like about the arborist wood chips.
Chris Enroth:Shredded leaves, I utilize those a lot, especially the the kind of the back portion of my yard. A lot of times, we'll pull the leaves or blow or rake the leaves off the lawn area there. We have a little woodland garden, and we will shred or kinda leave some of the whole leaves set there. And then by the time well, next fall comes around, most of them have decomposed and ready for more leaves. And I I recall when I interned at Missouri Botanical Garden, the mulch they used was called leaf mold, which is essentially just shredded leaves.
Chris Enroth:I think they even tumbled them and, like, they had, like, a dye so that it was a kind of all of a consistent dark color. But that was amazing mulch, and it's not heavy. You can carry, like, you know, a bushel with one hand. It's is I love shredded leaves because of the lightweightness of it. And as Ken said, shredding them is useful.
Chris Enroth:I I find shredding them helps also keeps them seated on the landscape. You'd think that the smaller particle size, they blow around a little bit more, But I think with the smaller surface area, they don't catch the wind as easy, and they don't blow around as far. So well, that is a lot of interesting information about those types of mulches, but we have a lot of other mulches to discuss and maybe some of those, maybe cons of some of these mulches. So, Emily, when it comes to the the the wood chips, are there any, negatives that come into play when using something like a a wood mulch?
Emily Swihart:There can be some well, like with anything. Right? There are some pros and cons. So with wood mulch or wood chips, one of the things to consider is that decomposition process. A lot of people get concerned about the tying up of nitrogen as it breaks down over time.
Emily Swihart:The research has shown that that can happen, but it's usually just at the intersection of the soil and the mulch level. So just by the process of decomposition, those microbes tie up nitrogen and utilize it, so it's not available to plants. I don't get worked up over it, obviously, I don't stop using wood mulch because it is eventually available to plants. And also, I hope my plants are not growing. They don't have roots in that intersection of soil and mulch.
Emily Swihart:I hope that they have roots deeper into the soil level. And so that would be where I would need those nutrients to be available. So that's one concern some folks do have when it comes to using wood mulch.
Ken Johnson:Another, I guess, potential concern for wood mulch. If you're getting the bagged stuff, sometimes you don't necessarily know where that's coming from. Some places will use, like, shipping pallets. They'll shred those and put that in the mulch and die them and stuff, which, you know, you don't necessarily know what's been on those pallets. I would hope it's not anything too toxic, but you you never know.
Ken Johnson:And and some of them, like the pine nugget, like bark, that stuff will kinda repel water and doesn't really break down much or all that quickly. So you kinda lose some of those benefits of the the decomposition. I've used some of that stuff in the past, and, you know, after three, four years, it still kinda look the same as when I put it down. Whereas your your typical wood melt, have your arbors wood chips are gonna break down. And you're gonna have to replenish that every few years because they are being broken down and returning those nutrients to the soil.
Emily Swihart:You said about pine mulch too. Repeated use of pine mulch can eventually create a more acidic soil profile, which is great if you're growing things that desire to have a a lower pH in the soil, so like blueberries. A lot of people will try to mulch with pine needles around them. That takes a while to to achieve that that pH change, but it can happen. You know, if that's the resource that people have available to them, say, like a windbreak, they're harvesting, you know, pine needles from a windbreak or getting bagged pine needles.
Emily Swihart:That can happen over time.
Chris Enroth:Now the interesting thing from our our time spent at the mulch seminar, was kind of in all of the research, they seem to conclude that the most effective mulch is thick. So, like, a thick layer in terms of weed suppression and a coarseness and texture, like a chunky type mulch. And so a lot I I think what comes into play here is a lot of we have, like, a thick layer that's able to suppress the weeds. The coarseness allows water and air to move and exchange with the soil, just what our plant roots need. And and I think that's probably why arborist wood chips seem to fit that bill just because wood chippers are not really designed to create a mulch for a landscape as we would often think that's uniform.
Chris Enroth:And wood chippers are also varied by just quality. We've gotten arborist wood chips that are absolutely beautiful, and then we've gotten the same wood chips that looks like looks like someone just went after with a machete or something. It looked awful. My wife said, you're never getting that again. Like, it does the same thing.
Chris Enroth:It's all variable shapes and sizes and allows good water and air exchange into the soil and keeps the beads down. Just put them in the backyard if you don't like the look of them.
Emily Swihart:We've had something similar happen too where you actually get some pieces of, like, twig. They would be, you know, 12 inch pieces or whatnot. So there is some variability, and that's important to keep in mind. We used it. It was fine.
Emily Swihart:Still served its purpose because that was not the entire batch of mulch. You know, there was a a wide range of different soil or different textures and particle sizes. But, yeah, looks looks matter too when it comes to mulch.
Ken Johnson:If we end up with bigger pieces, I just pull them out and use them for firewood.
Chris Enroth:Perfect. Yeah. I use mine to help me, do barbecue grilling and getting coals moved around and stuff. So they they serve a purpose. Yes.
Chris Enroth:And, Ken, you had mentioned, like, the pine, nugget or, like, that bark mulch. Because bark has is a waxy coating substance to repel water, they're hydrophobic. There's other materials, so, like, cypress, mulch, same thing. They have kind of they're kind of a hydrophobic or kinda water repelling nature to their cells, especially when they're shredded. And those shredded fibers, they knit together and they actually form a shell.
Chris Enroth:And I don't I like, this summer, I I really noticed that. So I I actually had some shredded mulch in the yard, and I noticed the difference between that and the arborist wood chips. With the shredded mulch, they knit together and form the shell. I I watered some of my plants, and the water just runs off. I go to the Arbus wood chips, I water, and it soaks in.
Chris Enroth:And definitely saw that difference this year. Both mulches were put down last year, and so they've both been around at about the same period of time. But if you do have shredded mulch, you can fix that by just cultivating that with, like, a, like, a rake or a three prong prong cultivator to break that shell up once or twice a year. Well, what about rubber mulch? Has have either of you had fun with rubber mulch before?
Chris Enroth:Because I have, and it's it's not all that I think that it's it's kinda chalked up to being.
Emily Swihart:I've only had experience with rubber mulch on the playground when I was a kid. I luckily have avoided using rubber mulch and or encountering it in any sort of professional capacity.
Ken Johnson:Yeah. But only playground is the only time I've ever seen it or not even used it. But yeah.
Chris Enroth:Well, I I remember at horticulture when we were in school down at Carbondale, some person came to the school and said, hey. We're gonna give you this amazing mulch. It's rubber. It never goes away. It keeps the weeds down, and we're gonna dye it your school colors.
Chris Enroth:And so, of course, you're like, well, heck. Yeah. We'll we'll do that. They gave a really good deal. It was cheaper than regular mulch.
Chris Enroth:Well so it was basically shredded tires. And in a lot of these cases, these are organizations that have a bunch of tires that instead of paying the landfill fee, they they put them where they're supposed to go. They shred them up, and they try to sell them to other folks for, you know, a small amount of money. And I think it was Linda Chalker Scott who we were taught listening to for the seminar, and she said, you know, if the EPA says that a tire outside of a landfill is considered hazardous waste, how does that change it when it's shredded up and put around our roses? And so, that was very interesting.
Chris Enroth:But in the case of my school, it's not permanent. Rubber actually does decompose. It does degrade over time. And, also, our school colors faded and left behind just what looked like shredded tires. And they put them in the parking lot beds.
Chris Enroth:And in the summer in Southern Illinois, it gets really hot. It just smells like hot tires. So it was gross. And and so rubber mulch is not all as chalked up to be. I think there are lots of components that go into making tires.
Chris Enroth:That stuff has to break down and go back into the environment. And what is the result of that? I don't think we have enough research to really say, but there are various, you know, plasticizers and accelerants, all those things that go into making tires. And is that good for our soy or not?
Emily Swihart:Well, it's a petroleum product too, a petroleum based product. And so you gotta think about what you'd anything that's decomposing on the soil surface is going to be then making its way into the soil and being available to plants. So what are those plants? How are they using them? How is it going to serve our landscape needs and or not or not serve them?
Ken Johnson:Go with a nut.
Chris Enroth:I I guess that then maybe brings us to our next one, which I I I did landscaping for a little while. I pushed a lot of wheelbarrows of this stuff, rock mulch. Everybody loves rock mulch. It's heavy. That's all I'll say about that, and I I I don't think I'll ever put that in my yard, but but we'll see.
Chris Enroth:I'm I'm still learning about, you know, the ways of mulch, I guess. But the I don't know. Ken, Emily, how do you feel about rocks as mulch?
Ken Johnson:Not a fan.
Emily Swihart:No. And,
Ken Johnson:yeah, in our the house we bought, they had some pea gravel in areas, and that stuff's easy enough to move with a shovel. And we just put that around the near the foundation of the house because it's fairly easy to maintain. But the house my parents moved, they got lava rock everywhere, and I hate that stuff. Badging because you cannot shovel that, you know, pick it out by hand. And we're doing theirs, a level of lava rock and then landscape fabric and another layer of lava rock underneath that and plastic under that.
Ken Johnson:So needless to say, those beds did not get cleaned up because it is an absolute pain to deal with.
Emily Swihart:Yeah. I think that layering of landscape fabric or most oftentimes plastic material underneath the stone, the theory goes that it is going to keep the rocks from, sinking into the soil profile. Right? It's going to keep a barrier between your mulch and your soil, and it's gonna keep it clean. It's gonna suppress weeds underneath.
Emily Swihart:Like, this is, I think, the traditional thinking for applying a a sort of fabric or barrier material underneath the stone. Beyond besides being heavy, hard to get rid of if you ever do want to commit to it or or, I guess, uncommit to it or if you've inherited it from, you know, a land purchase. It doesn't actually work. So with with, you know, having a fabric underneath your stone, over time, you're still gonna build up composted materials. Like, you're still gonna have leaves fall onto that that bed.
Emily Swihart:You're still going to have the breakdown of those materials, and so you'll have this organic matter that's just living within and filling in those those spaces of your rock mulch. There's gonna be weeds in there. So if you're using mulch primarily to suppress weeds, that's not going to long term be a solution for you. You can't really reapply. Or I guess you could reapply.
Emily Swihart:It would just be another layer of fabric with more stone on top of it, and it just kinda, like, perpetuates this this challenge. It's also not gonna be permeable to water or air, so the soil underneath is going to be sacrificed in a major way. And so this goes I I guess we can get into the whole topic of using a a barrier between any sort of mulch material and your soil, but it just doesn't it doesn't pan out. The theory doesn't play out in the landscape. And so I guess it's a long winded way of saying, I'm not a fan.
Emily Swihart:Not a fan of rock mulch.
Ken Johnson:And with rocks, I'm I'm sure they've done studies, and I just haven't looked at them. But I feel like, you know, if you're doing it around plants, those plants those rocks are gonna retain heat. It's gonna be hotter, and it's gonna be hotter into the night too. And a lot of plants, you know, you need that that cooling off in the evening too. So I think that's another, in my opinion, another strike against rocks.
Ken Johnson:Maybe not lava rock. Maybe that doesn't get quite as hot, but some of your larger, more solid type stones.
Emily Swihart:Yep. There is yeah. I mean, we just spent a few minutes kind of nagging on rock mulch. There there have been some studies, though, that it does help with the temperature moderation of the soil. It does shade the soil.
Emily Swihart:And so if you don't have that fabric in there above the rocks, yeah, that reflective heat can be detrimental to plant health. But below, there is still some benefits of having a mulch, even if it's rock mulch versus not having anything. To me, looking at the evidence, it's not worth it still. There's a to me, there's better options for mulch on the landscape besides rock.
Chris Enroth:I think from a horticultural standpoint, whatever mulch we choose, we want it to contribute back into the system, and rock doesn't. Or it it does so very slowly over the course of multiple generations of humans. So, yeah, in in the time scale that we will be gardening, yeah, rock doesn't doesn't do it for us. So I that's that's kinda why I kinda turn my cold shoulder to rock. And I know, Ken, why you don't like lava rock.
Chris Enroth:Because, actually, University of Nebraska, Lincoln has shown that lava rock deters snakes. And you like your snakes, don't you?
Ken Johnson:Snakes are cool. Snakes are cool.
Emily Swihart:It's hard on their little bellies.
Chris Enroth:It is. It is. Well, I I think there's one more mulch I'm gonna throw out there, and it's one that I have been seeing more and more and has been driving me crazy, Astroturf. Have you guys seen the trend of putting ripping out your lawn, ripping out your landscape beds, just putting astroturf down? We're not talking about a desert.
Chris Enroth:We're talking about Midwest. Like, it's crazy.
Ken Johnson:I Not long. I mean, athletic fields, man. Not long. I haven't seen that.
Chris Enroth:Mhmm. Check out the YouTubes. I
Emily Swihart:haven't seen it either. I was gonna say, I've seen it on an increase on, you know, sports fields. But
Ken Johnson:Mhmm.
Chris Enroth:Well, Aaron Rodgers aside, we could probably get into that right now. But putting a fake or a it's kind of like rubber mulch, a a poly based or plastic based material over top of the soil. A an Astroturf lawn is not a no maintenance lawn. It has to be cleaned. It has to be vacuumed, and they have a lifespan.
Chris Enroth:Like, they all will eventually begin to degrade and fade and and not look very good. So all that has to get ripped up and sent to the landfill. And now you're left with a soil that for the last, like, seven to ten years has not had any inputs on it. And I I just just my word to say, not a fan of astroturf being used more and more to cover our soils.
Ken Johnson:And that stuff gets hot too. Mhmm. Uncomfortably hot.
Chris Enroth:Yeah. Yes. It can burn people.
Emily Swihart:And pets.
Chris Enroth:Mhmm. Alright. Well, we have a series of quick questions here. We'll promise we'll be as fast as we can. And I'll we'll just lightning fire here these off, to all, to Emily.
Chris Enroth:So I'll I'll start here. Emily, tell us about allelopathy. Is that a problem with mulch?
Emily Swihart:I'm glad you asked. And the short answer is no. Not really. So with allelopathy, it has been shown so it's a chemical production in plants. It's a defensive mechanism.
Emily Swihart:Right? We we probably have covered this before. But just a quick refresher. Some plants do produce some chemicals that inhibit the growth of others. This is to allow them to not have the competition around them.
Emily Swihart:It's usually live plant material that is going to be producing these chemicals. So by harvesting, let's take a walnut tree, for example. It's probably famously known for suppressing some growth around it. It doesn't produce that hormone once it's been harvested and created made into mulch. So that's not just it's not panned out in the research that we have, that it's not going to be a transfer from live plant material to plant material then uses as mulch.
Emily Swihart:So no worries.
Ken Johnson:Alright. Next question. Will mulch from diseased trees infect plantings?
Emily Swihart:Again, not usually. The size part like, the size of mulch being transferred, the you know, the fact that it is a dead or or soon to be dried up remnant of a a once living plant material, most pathogens and pests are feeding on the the harmful ones would be feeding on live plant tissue. And so by harvesting it, you're not going to have that transfer into your your planting bed. It also is not probably hypothetically, let's say it's there in the soil or it's in there in the mulch, and it it could transfer. There are some that could potentially transfer.
Emily Swihart:If it's not in direct contact with the plant itself, a like a contacting the roots. Like, if you're not incorporating your mulch into the soil, which thereby makes it not mulch. You know, if you don't have that root to mulch contact or that plant to root contact, there's a significantly reduced chance of pathogen transfer. So something I don't really worry about either in my landscape. If you have susceptible plants or your prized plants that you're really concerned about, then you can do some research and investigation and make sure that you're not getting mulch that could potentially infect them.
Emily Swihart:But that is a leisure activity that I don't partake in.
Chris Enroth:I think also one of the sessions we sat in on, they talked about the increase in biological activity and how that creates more competition for pathogens. So I I guess that I I I didn't really follow some of that science. I was maybe a little maybe I needed more coffee at that point in time. But, definitely, they they saw, like, a a reduction, I guess, in some of the the Phytophthora rots, when they incorporated more mulch, in their in their landscape wood mulch, I suppose I would say that.
Ken Johnson:And I know for, like, for compost, and I would assume it'd be similar for mulch. You know, those organisms are breaking down the compost and stuff. They kinda you know, they'll may attach to the roots, and they're taking up the areas. They're attached to the areas where the pathogen would. So the pathogen doesn't necessarily have somewhere to attach to the plant.
Ken Johnson:So it seems kinda similar with mulch. So you've got those beneficial microbes that are gonna be breaking it down, and they're kinda competing with the pathogens for those attachment sites and things like that. So they're they're kinda out competed. And those pathogens are in less than ideal environment because they're they're gonna be on living plant material. Once that stuff is dead, they've got a limited time that they would be able to move.
Ken Johnson:So if if you do were concerned, you know, if you get fresh stuff, let it sit for a little bit before you apply it.
Emily Swihart:Yeah. And, also, when you have an organic or a natural mulch decomposing and you've got, you know, those microbes working in there and you've got a a well balanced ecosystem at that scale, you know, we talk about having a diversity of plants and, usually you at the larger scale, this goes down to the microbe level too. A healthier ecosystem is going to be more resistant to and be able to ward off more pests and pathogens and have more vitality than one that is is suffering or is missing some of those critical elements.
Ken Johnson:You have a whole podcast on fungus and stuff like gros and mulch. Your dog vomits and your stink horns and artillery fungus and all that.
Chris Enroth:We would have to censor some of those images, though, Ken, that that arise from the mulch. They they don't look they're a little phallic in shape. So
Emily Swihart:We're a public university, so, yeah, we need to be upstanding members of this community.
Chris Enroth:Check out this mushroom. Looks like something else. Okay. We we've already mentioned this. You already mentioned this, Emily, but let's just let's rehash this here just for a second.
Chris Enroth:Nitrogen. Does mulch tie up nitrogen in our soil?
Emily Swihart:No. Again, no. Nope. Yeah. Like I said earlier, it it can tie up nitrogen levels at that intersection between the soil level the soil surface and the mulch just because that's what decomposing does.
Emily Swihart:Like, those microbes use nitrogen in that process, but not so much that it is something to be concerned about. It does not make the argument against natural mulches weaker. I think it makes it stronger because it eventually becomes available to plants. And so, nope. Not a worry we need to be concerning ourselves with.
Chris Enroth:Don't till it in.
Emily Swihart:Don't till it in. Nope. That's a different story. Again, that's not mulch.
Chris Enroth:So Yeah. That's an amendment. Yeah.
Emily Swihart:It is.
Ken Johnson:Yep. And not a very good one. Mm-mm. No. Alright.
Ken Johnson:Another one we've kinda briefly touched on. Should we or should we not use landscape fabric when we're using mulch or just landscape fabric in general?
Emily Swihart:Again, no. I feel like I'm saying that a lot. No. We shouldn't. The natural ecosystem, that kinda knew what they was doing when it all, just dropped organic matter on top of the soil and let it do its thing.
Emily Swihart:But no, again, that theory is that it'll be another additional man made layer between weeds that are soil borne and plants so it can help suppress some of that weed or serve it like a weed barrier. It doesn't play out because as we know, every year plants put on more seeds, and so those just fall on top. So it's not really suppressing weeds. What it can also do is so they'll often sell it as being porous, so water can penetrate, air can penetrate through, which are critical elements for root growth and soil health. Over time, quickly, not a lot of time, those pores fill up.
Emily Swihart:They get clogged up with soil particles or getting particles. They just get plugged up, then they don't allow for an air exchange or for water to penetrate through. And so your soil becomes anaerobic in a sense, and it really can suppress some root growth.
Chris Enroth:Our running joke was as landscaping the fabric lasts long enough or works to the point where the warranty runs out, and then we're done. We don't have to worry about it. Yeah. About a year. Yep.
Chris Enroth:Yeah. So I put mulch down whenever I get my hands on it because it's it's, like, matter of budgeting time and budgeting money. And whenever I can get mulch on the ground, I will. But is there a seasonal, like, time of year that works best? Spring, summer, fall?
Chris Enroth:What is there any recommendation?
Emily Swihart:There are some guidelines. Certainly, having some mulch on the landscape versus not having mulch on the landscape, whenever you can get your hands on it is okay. There's some things to be aware of. So I think traditionally we think of applying mulch or freshening up our mulch in the spring, which is a good time to apply mulch. It does help with weed suppression.
Emily Swihart:That's a lot of times when some of those annual seeds are going to be germinating. By applying mulch in the spring, the theory is basically that you're intercepting the sunlight and so those seeds are not going to germinate because they don't have access to sun exposure and or it creates a physical barrier that they cannot push through, and so you would have weed suppression. Now, one of the benefits that mulch helps provide is temperature moderation within the soil. Here heading into fall coming up and heading into winter, it might be beneficial to assess your landscape and the mulch condition, understanding that mulch on a landscape preserves moisture and air in your soil or dry soil is going to have a more rapid change of temperature than moist soil, soil that's gonna have a lot of moisture in it. And so by reapplying mulch, you can keep more moisture in your soil throughout the winter.
Emily Swihart:And we know in the Midwest, these winter months can be really, really dry and desiccating to plant material, which can cause winter burn or dieback. So given this year that we've had with this really, you know, dry soils with, you know, almost everybody being in drought conditions or near drought conditions, I will be assessing the mulch situation in my landscape and reapplying two newly planted plants, like newly planted woody plant materials or perennial beds, I wanna make sure that the yeah. I will also be watering those, and I think in a couple weeks, we'll be talking about water in the landscape. But I wanna make sure that those soils and those root systems stay hydrated. It also helps with frost heave, so having some mulch on there and avoiding big temperature swings can help keep your plants actually rooted in the ground.
Emily Swihart:I will probably not be reapplying mulch to my well established woody plants because one of the cons or one of the risks to having, like, reapplied mulch right now is that it does keep soil temperatures warmer longer, which can be detrimental when plants are trying to acclimate to the upcoming winter months. So those are the kind of the pros and cons or the cost benefit analysis that you need to do when you're looking at where and when to apply mulch to the landscape. Like I said, I think mulch is good on the landscape or on your plants almost always. There's just that slight risk of delay of acclimation for winter. We don't know what kind of winter we're gonna have.
Emily Swihart:If it's a mild winter, it's not gonna be as risky as if it's, you know, really harsh, cold, early winter.
Ken Johnson:And I found in in, like, vegetable garden settings, sometimes if you got a pretty good mulch on your in your vegetable garden, those soils are a little slower to warm up. So if there's something you wanna get in early, you may wanna clear a spot. At some point in the spring, let that soil warm up. But otherwise, you're gonna be digging into frozen ground later than you would normally be. But I I think the the benefits far outweigh that that slight delay.
Emily Swihart:Yeah. You also have to consider the soil type. So if you have, like, a compacted soil or a soil that is more clay like in consistency, that can retain moisture on its own. And so by adding mulch to the top of it, whether it's, like, for winter and, like, the wet spring, like, early like, warming up and drying out Or just in, you know, the summer months, like, if you are conserving moisture in a soil that already conserves moisture, it can be problematic for root systems and create that anaerobic soil conditions. They don't lead to root rot and other challenges.
Emily Swihart:So pay attention to the kind of soil that you have when you're making decisions regarding mulch. To that end, I will say that over time, mulches on a clay soil or a compacted soil, that decomposition that we were talking about earlier can help improve the soil structure. So it just would affect how much soil or excuse me, how much mulch you would apply to the surface. I would still advocate for having a a natural material wood mulch on top of clay soil. Just when and how much you apply would be the variabilities.
Ken Johnson:And I think the particle size would play a a big part in that too. I think your your bigger stuff, you can get away with more of it's, like, sawdust than you're than you're asking for trouble on on heavier soils.
Chris Enroth:Yep. Yeah. I find the sawdust on a heavy soil just why it just runs off. It can't get ahold of anything. It just heavy rain just washes it off like it's on a Yeah.
Chris Enroth:Piece of glass or something.
Emily Swihart:Yeah. Those, like, singular or evenly sized particles and those smaller part sized particles just, like, lock together. You know, it's how clay works in the soil. That's if you, you know, kinda step back and look at now this is a whole another fun podcast that's talking about soils. But if you look at particle size and shape, clay soil particles lock together.
Emily Swihart:That's why they repel water, and that's why they're hard to have root growth penetrate through because they're just they're small and they tie up.
Chris Enroth:So if we had a a kind of a summation of everything, lay it on thick, keep it chunky. That's how I like
Emily Swihart:We need shirts that say that.
Ken Johnson:Just like this. Butter.
Emily Swihart:Yes. That's right. Peanut butter.
Chris Enroth:Lay it on thick and keep it chunky. Oh, yeah. I like that. Well, that was a lot of great information about mulch. That wasn't so bad.
Chris Enroth:I feel okay now. That wasn't as bad as I thought. I I still feel like I'm a I'm a professional horticulturist now. So very good. Very good.
Chris Enroth:Well, the Good Growing podcast is a production of University of Illinois Extension, edited this week by Ken Johnson. Thank you, Ken, for that nice little audible helping me out this week and editing two times in a row.
Ken Johnson:So
Chris Enroth:thank you, Ken. And a special thank you to Emily Zweihardt for joining us and answering all of our mulch questions and and making me feel better about my spot in my career and where I'm at in life. So thank you, Emily.
Emily Swihart:Oh, you're welcome. You're doing great, Chris. You're doing great, Ken. Very happy to be you guys.
Ken Johnson:Thank you for being on, Chris. No problem. Happy to do it.
Chris Enroth:Thank you.
Ken Johnson:Mhmm. And let's do this again next week.
Chris Enroth:Oh, we shall do this again next week. We are going to be talking with state climatologist Trent Ford about what's up with the weather this year and what to expect this fall and early winter. The climate prediction center has their numbers out and he is gonna share those with us. So it's gonna be a fun show. So listeners, thank you for doing what you do best and that is listening or if you're watching us on YouTube watching.
Chris Enroth:And as always, keep on growing. Wait. Were you taking bets on something?
Creators and Guests
