Tasha Greer: Weed-Free Gardening

When talking about weeds, people use words like enemy, battle, and war. No one wants weeds in their garden, right? Well, it depends!

In this episode, author and gardener Tasha Greer talks about why we can't win the "war on weeds," and why we don't really need to. In fact, it's entirely possible to make peace with weeds in our garden.

Tasha goes way beyond the usual suggestions for mulching and pulling weeds. In fact, she tells us why pulling weeds is actually a bad idea. And mulching can even cause problems when used with the wrong weeds. Instead, she talks about what we can learn from our weeds and how weeds can actually help us.

Full show notes here -- https://thriftyhomesteader.com/weed-free-garden/

To see the most recent episodes, visit  ThriftyHomesteader.com/BookChat

Transcript

Deborah Niemann  0:04 
Whoever you are, wherever you live, whatever size your living space, you can do more than you think to lead a greener lifestyle. In the "Sustainability Book Chat," we are talking to authors and experts about all the different ways that achieving sustainability is within your reach.

Deborah Niemann  0:22 
Hello, everyone, and welcome to today's episode! This is going to be a really interesting episode, and will probably, hopefully, change the way that you think about weeds. Today, we are joined by Tasha Greer, the author of Weed-Free Gardening: A Comprehensive and Organic Approach to Weed Management. Welcome to the show, Tasha!

Tasha Greer  0:50 
Oh, thank you so much for having me! I'm really glad to be back here talking to you again.

Deborah Niemann  0:54 
Yeah! For those of you who listened to the podcast before, Tasha was also here last fall talking about her other book, Grow Your Own Spices, which was a very interesting and fun conversation, too. And so, she's got a new book out now about weeds. Which, I think everybody who gardens has questions about weeds. They have concerns about weeds. A lot of people feel like it's a constant battle with weeds. And one of the really cool things about your book is that it doesn't come at it from that battle perspective. Can you tell us a little bit about your philosophy of weeds?

Tasha Greer  1:31  
I live on this property that had literally no soil when we moved in. And so, I started adding some organic matter. And I started getting a few weeds. And I was so excited, because something was growing here! And so, I started studying weeds and learning more about them, and I began to understand kind of their function in developing soil. And, as a result of that, I really kind of developed an admiration for weeds. So, whenever new ones would pop up, I'd be like, "Oh, what does that weed mean?" And so, I started realizing that weeds aren't just sort of, like, accidents that happen in our garden; they are a response to things that are happening underneath in the soil. They're kind of, like, messengers of the changes taking place there of, you know, what's in your soil seedbank, of the condition of your soil. 

Tasha Greer  2:19  
And so, I started just kind of thinking of them as information-givers, and using them to figure out the next steps to improve my soil and be able to grow the plants I actually wanted to grow. And so, I really just kind of developed this approach of identifying weeds, figuring out, you know, what they're telling me about my soil and what amendment to do next—because you're always improving your soil. You know, when you start from soil that's not in good shape, you have to just keep working it for years and years. And so, then I could decide, "All right, well, this is where my soil is at now. And I can add some compost to amend it, or I can think about putting a different plant here, that's, you know, more like the weed that showing up." And so, I just started letting basically the weeds guide the practices in my garden, and I had such better results. I mean, I started growing really everything better. And it just made me realize, weeds are not the enemy. They're an important tool, and also an information-giver. You know, it's like a conversation with your soil when you start studying your weeds.

Deborah Niemann  3:24  
Another thing that you really flipped on its head in this book is the idea that a weed is "a plant that simply growing in the wrong place." So, can you explain why you disagree with that?

Tasha Greer  3:37  
Yeah, absolutely. I think a lot of organic gardeners, we say that, that "a weed is just a plant out of place." And, you know, it's a mark of respect, saying that we know this plant has value, but we just don't want it in that location in our garden. But the thing is, the place where the weed pops up in our garden is the place where it's well-suited to grow. Nature could be choosing from probably 50, or 100, or even 300 different kinds of seeds to germinate in that one location, because we always have so many extra seeds sitting around in our soil. But, nature chose just that weed, you know, or those two weeds. And so, if you can sort of look at those two weeds and realize that, okay, they're here for a reason. They're a response to some condition in the soil, something that's either changed—like, maybe the pH is changing, so it's triggering the germination of some new kinds of seeds—or maybe the soil is running out of water, so it's triggering the germination of plants that grow well when the soil dries out. 

Tasha Greer  4:36  
You know, so, if you can realize that that plant is actually there for a very important purpose, then you can kind of sort of reverse engineer and figure out, you know, "Okay, it is in the right place. I don't want it here, but what can I do so that it doesn't come back?" You know, maybe I need to water more, if it's one of those weeds that responds well to dry soil. Maybe I need to add more organic matter, if it's a weed that grows in, like, compacted, distressed soils. You know, if it's something that makes its own nitrogen, like a nitrogen-fixing legume—a white clover or something like that—then probably there's not enough nitrogen in the soil. It might be compacted, so there's not enough air spaces or water spaces. So, the weeds that come up are really sort of nature saying, "Okay, this is the plant that belongs here. It is exactly in the right place, because it's going to grow well." So, if you just change your perspective on that, then you can start looking at that weed and saying, "Okay, well, what, you know, what's going on in my soil? And what really should be growing here, or what should I be doing if I don't like those conditions?"

Deborah Niemann  5:41  
One of the things that I thought was kind of funny when I was flipping through your book is that it looks like you have a Great Pyrenees puppy named Luna. Which, so do I!

Tasha Greer  5:53  
Yeah. And Luna is... She's allowed in most places on our homestead, because she, you know, kind of keeps the deer away and keeps our animals safe. But she is not allowed in any of my highly cultivated, like, vegetable garden or flower garden areas, because she has this mass of fur that gets covered in weed seeds. And so, if she were to go into my garden, she'd just be dropping all sorts of new weeds from, like, around our pond area and in the woods. And, you know, she'd literally be transmitting all sorts of new weeds. So, she's a weed spreader.

Deborah Niemann  6:30  
It's so funny, because, like, I saw this picture, and I'm like, "Why is there a picture of a dog in here?" Because that's something I never thought of before. You know, like, you think of the ways that weeds are spread and stuff, but it never occurred to me that, like, my dogs could be spreading weeds.

Tasha Greer  6:48  
Oh yeah. Dogs, cats, voles, and moles, and all the underground critters, they move things around as well. Of course, water does. And wind does. You know, I always think of dandelions, and like, you know, blowing on them to make wishes and spreading all those seeds around—and what a joyful, wonderful thing, but your neighbor with a lawn is screaming at you for it.

Deborah Niemann  7:14  
I pretty much feel like a one-trick pony when it comes to weed prevention, because I'm just like, "Oh, just mulch." You know, there's cardboard, mulch, wood chips, straw, whatever. You go a lot deeper than that in prevention—with one of your great things, like, don't let your dog into the garden. So, what are some of the other things that people can do other than mulch—and now, we know, keep the dog out of the garden?

Tasha Greer  7:42  
Well, I think, you know, it really depends on the condition of your soil and the kind of weeds that you're looking at, you know? I mean, so mulching is really terrific for annual weeds that, you know, only germinate close to the surface of the soil, but it's not really going to do anything for the weeds that germinate deeper underground—several inches, you know, underground. But, what mulch does maybe to kind of help with that situation, is it keeps the temperature of the soil sort of moderated; it retains moisture. And so, those seeds that are hiding, you know, 2 or 3 inches underground may not get weathered as quickly, so they may not get cold-stratified, so they might not germinate. So, that one is really an effective strategy in a lot of ways. 

Tasha Greer  8:23  
But, you know, I think there's a whole bunch of weeds that aren't going to respond well to that. So, if you've got, like, rhizomatic spreaders, if you've got weeds that are spreading by runners, either above or underground the soil, when you add mulch to a situation like that, it's like a flame to fire. For those, you know, they're really just going to start running through your mulch and spreading even faster through all that moisture and organic matter. So, in a situation like that, mulching over it won't prevent the problems. So, you actually are going to need to remove that weed, or sort of create some sort of barrier around it. So, you know, say, "This is the zone that it's in now, and I'm going to make a little trench, and I'm not going to let it go any further past that." So, there are situations where mulch isn't going to be sufficient. 

Tasha Greer  9:09  
And a lot of times, mowing will help. Because especially, you know, if you can just, every time the plant starts to grow, keep repeat mowing it. I think a lot of times the advice is, you know, every few weeks, go back and mow it; that's usually not often enough to really kill a weed, because they'll have some reserve of energy in the soil. So, it's literally, every time you see it starting to grow, you're gonna want to go mow it. And then, you also want to, you know, sort of draw a line and say, "I'm not going to let you get past this point until you finish controlling it." Or, you can pick it up, and then you can plant a cover crop and heal the soil, and then, you know, start over that way. 

Deborah Niemann  9:47  
One of the things that I found really fascinating... This was years ago. We were at the, I think it was the Museum of Science and Industry, in Chicago. And they had a picture that was, like, 10 feet tall of how a lot of prairie plants—aka weeds—can survive so well on their own with no help whatsoever from humans. And they show, like, this little bitty plant has a root that's, like, 6 feet down into the ground, you know. And when I saw that, I just thought, "Oh my gosh, there's nothing we can do. Like, we'll never beat something that's got roots that deep."

Tasha Greer  10:27  
Well, and there is truth to that. You know, it's definitely more difficult the deeper the root system, because they can always draw on those reserve root system. But, if you repeatedly just chip away at the crown of the plant, it really can rob it of energy. It makes it more prone to diseases, you know, fungal pathogens, and things that will sort of decompose it. So if you can dig into the head a little bit, it works. But another thing is, a lot of those plants really require full sun. And so, light deprivation is another technique. Maybe not mulch, because they'll just grow right through it, but you could, you know, put some kind of... I like a pond liner, if I'm going to use it, because they're UV-protected, so they don't tend to decompose into your garden very quickly. And they're heavier. So, if you throw a pond liner over an area and just deprive those sun-loving plants of light, you can eventually you know, time them out. So, it's really just about using strategies to weaken the plant enough till it finally gives up and stops trying.

Deborah Niemann  11:25  
I've heard from old-time gardeners in Illinois this old saying. Because we have problems with thistle here. And the saying is: Cut thistle in May, it will stay; cut thisle in June, still too soon; cut thistle in July, it will die. And the reason behind that is because by June, it's bloomed, and it's spent all of its energy on producing that bloom, but then you want to get it before the bloom goes to seed, then. So, is that old saying good, or no?

Tasha Greer  11:58  
That's absolutely brilliant. Every plant, at the time when a plant is flowering, it uses so much of its root energy to put up those flower heads and to start forming the seeds, that you can actually feel it release the soil a little bit; the roots don't grip as tightly. So, at that point in time, mowing it down—if it's an annual or biannual—you can just mow it down and it'll eventually die, because it's done its job. If it's a perennial, then you could either repeat mow it—you know, you might have to do it for a couple of years. Or, you could, you know, try to dig out a bit of the root and actually plant something on top of it even, to crowd it out. But yeah, definitely the best time to kill a weed is when it's flowering, or you know, just about to flower, or right after flowering, but before it sows more seeds, because of course, those seeds are then going to be another weed hazard.

Deborah Niemann  12:54  
One of the pull quotes in your book that I think is really cool—and I think a lot of people, when they look at dealing with weeds, it's very short-sighted. And so, one of the quotes that's, like, on the first page of part two, which you call "Maintenance," is that, "Temporary remedies only invite weeds to thrive."

Tasha Greer  13:12  
So, one of the things I know for sure—because I used to have a lawn that I used to treat chemically. And this was a long time ago. I gave up using any kind of herbicide, organic or otherwise, back in 2008. But I would notice that the places where I was putting down my, like, crabgrass preemergence, or was doing spot treatments, I would notice that my grass—no matter what I did—would never grow as well there, and that more weeds would just come. And so, it's just, the thing is, when you start applying an herbicide, when you start using any sort of one-time product or preventative product, you're going to destabilize your soil life. And that is going to set off a whole bunch of other weed seeds that are already lurking in your soil. 

Tasha Greer  14:00  
So, another sort of key facet of the book that I really sort of try to hammer home —if people read the, you know, the words and not just the pictures and things—but soil stability is really the sort of underlying fundamental thing that you need to aim for if you don't want more weeds. You need to be able to have sort of regulated temperatures by having a lot of mycorrhizae, and you also need sort of stable bacterial populations. You do that by feeding your soil a steady supply of carbon, which, you know, plants are what supply soil with carbon, and also things like compost and mulches. You know, so you don't just want to think about removing or eradicating weeds; you want to think about stabilizing your soil. And so, that's where, like, maintenance is really sort of getting into the soil stability. It's managing your drainage. You know, it's applying organic matter, like compost and cover crops and mulches in the right ways so that you're not further compacting soil, or, you know, retaining too much moisture, or suppressing or encouraging the wrong kind of soil life. 

Tasha Greer  15:09  
So, good garden care is really what prevents weeds, not ripping them out or mowing them down. You'll have to do some of that, because those weeds are already growing. So, you're trying to garden in their territory. And you'll have some that emerge, even when you start repairing your soil, because if you change your soil pH, then that's a sudden change to your soil. If you apply lime or sulfur, you're going to get a reaction out of the soil; it's going to send up a whole lot of weeds. But the faster you can get to soil stability, to, you know, having a lot of plants growing, to having a regular supply of organic matter and carbon going into the soil, and you know, retaining the right amount of water—not too much, not too little—then you'll stop getting weeds. They just won't even show up anymore.

Deborah Niemann  15:54  
Your book just goes so far above and beyond the things that I thought of as weed control. Like I said, I've always been such a one-trick pony. I'm like, "Oh, just mulch it."

Tasha Greer  16:06  
But that's a good trick! You know, I mean, a lot of people don't do that. And so, they miss out on that opportunity to have a steady carbon diet, you know, for their soil to keep it healthy.

Deborah Niemann  16:16  
Yeah. So, so many things about this book just surprised me. Like, "What? What? How does that? I don't get it." Like the dog. I'm like, "Why is there a picture of a dog in here?" And another one that I thought was really cool—and like, I think this is gonna help me solve a big problem that we've had that just gets worse and worse every year. And that is, you talk about rain gardens. Because, like, we have a gravel driveway, and we constantly have to add gravel to it, which means that the areas on the side are just getting lower and lower, and they're turning into these little swamps. 

Tasha Greer  16:48  
Yep.

Deborah Niemann  16:48  
And so, you've got this really neat section here on rain gardens, and about how they can capture and collect rainwater, and drain quickly, and...

Tasha Greer  16:58  
The thing is that a lot of times some of your weeds are, like, washing down from other places. You know, the seeds are rolling across the soil, the water that runs off your driveway is, you know, then going to be pounding them into the soil and causing more weeds. So, it's also going to be causing these, you know, these moisture problems in your garden bed. You know, you might get too much rain at some point; it might drain too much in different areas. 

Tasha Greer  17:23  
So, one of the big things that I spent some time on in the book was landscape drainage. Like, you really don't just want to think about the drainage in your bed; you want to think about everything around the areas that are draining into your garden beds, because you need to control the amount of water that flows in and out of your garden. And so with things like rain gardens, and, like, I have a lot of gravel pads that I've put in that are actually you know, just enormous water and filtration impoundments, because I garden on a mountain. You know, I have, like, a 300-foot elevation change, you know, from my greenhouse to my kitchen garden. And so, if I didn't do something to control drainage, like with swales and hugelkulturs and rain gardens, all of that would be flooding into the one flat area where I grow my vegetable garden. And that would be, you know, just washing all sorts of weeds in, and, you know, so, you also sort of have to control your points of entry. 

Tasha Greer  18:18  
And, you know, if you have lots of water coming into your garden, and then it dries out, and then, you know, more comes in, you have these like flood and famine cycles—all of that generates weeds. So, creating gardens that are stable because they manage your rain flow is really going to cut down on the sort of drainage problems that trigger weeds to germinate from deeper in your soil.

Deborah Niemann  18:43  
Another thing, too, that surprised me—this book is just full of surprises—was your section on cover crops. Because, I always just think of cover crops as being, you know, good for the soil in terms of, like, not leaving it barren during the year and in terms of green manure, you know, plowing it under and stuff. But you also talk about using cover crops for weed suppression. Can you explain how that works?

Tasha Greer  19:08  
Yeah. I think one of the big reasons that people get a lot of weeds in their gardens, especially vegetable gardens and things, is because you have a whole bunch of soil life in there. If you add some compost, you're adding a bunch of soil life. Your soil life feeds on carbon. And so, if you take out your plants and don't put in some new plants, you have a whole bunch of soil life in there that, they're going to be hungry, because they don't have plants feeding them carbon exudates through the root system. And so, what they do is they kind of get overactive in the soil looking for carbon, trying to find new root systems. They literally, actually, like, almost till underneath the soil. You can't see it, because they're microscopic, but the amount of disturbance that they do moving around looking for new carbon sources actually causes some of the seeds and things inside the soil to weather. The, you know, outer shells wear; there's some chemical reactions that take place. And so, that activity actually causes dormant weed seeds in your soil to germinate. So, you get these, like, big flushes of weeds, because it's not just because your soil is bare, it's because the soil life underneath the ground is actually trying to find food. So, they're actually triggering these dormant seeds. And so, you get all these weeds. 

Tasha Greer  20:22  
If you instead go ahead and plant a cover crop—you know, something that you sow close to the surface of the soil that's going to germinate quickly—then those plants are going to put down roots, they're going to be feeding the soil life, and then the soil life aren't going to be running around frantically causing disturbances that trigger all sorts of weeds. So, it's so hard to, like... You can never see these things, because it's all microscopic. And even if you look at it with a microscope, you don't understand, because they just look like all these critters racing around. But there's just so many of them in an organic garden, that if they don't have roots to, you know, hang on to and to feed from, they're going to be racing around causing soil disturbances. And so, by putting those cover crops, you're offering a food source to the bacteria that, you know, are normally feeding your plants; you're feeding them as well. And so, that really just cuts down on a whole lot of that dormant seed germination.

Tasha Greer  21:19  
You know, and then, you also get those sort of typical properties, in that you've got an aboveground leaf mass that's going to be shading the soil, so the, you know, annuals won't be able to get started, because they won't see the sun. You know, and you're continuing to add more carbon to your soil. So, you're improving it while these are growing as well. So, you're using them, actually, to achieve that soil stability that's going to result in weeds not germinating very often.

Deborah Niemann  21:43  
So, if you were going to use cover crops, could you do that with, like, say, tomatoes or peppers? If you're growing them in your garden?

Tasha Greer  21:50  
While growing tomatoes or peppers? No. Normally in a situation like that, you probably want to use some kind of mulch. And compost would be your best mulch for that, because when you put down carbon-rich mulches like straw and things on hot soil, what happens is the bacteria get excited, and they start decomposing that straw, and so they take some of their attention away from your plants. So, I really like to put very well-aged compost as a, you know, cover underneath any plants that I'm actively growing during warm weather. Just because that will prevent a lot of that surface weed sowing from happening, it'll be feeding your tomatoes, and it won't overexcite your bacteria and take their, you know, attention away from your tomato plants. 

Tasha Greer  22:35  
But I do recommend, you know, if you've got a space between, like, when your tomatoes time out—you know, if you're not going to be planting some cabbage or something—then definitely throw in some oats or some mustard or something that will germinate pretty quickly and cover that area, so that it's not bare through winter. And I know, you live in a very cold climate, so those will end up getting winter chilled, but they'll still provide that green manure after they die back.

Deborah Niemann  23:03  
Right. Yeah, well, it's good to know I picked the right thing, then, when I chose mulch for my tomatoes. 

Tasha Greer  23:10  
Yeah. 

Deborah Niemann  23:12  
Well, I just love this book. It's so great. And there's... It just goes so much deeper than what you would think. Like, when I look at a book, it's like, "Do I need to read this?" And then, I look at how long it is. And I'm like, "Okay, yeah, I could sum up what I know about weed control in, like, five sentences. So, I think this book probably can teach me a lot." And I mean, it just went so far above and beyond all the things that I expected for it to talk about. Like, and just so many little things. Just really great information. 

Deborah Niemann  23:43  
Is there anything else that you think readers should know? Like, what's the one big takeaway that you think people should take from this show?

Tasha Greer  23:52  
Well, the thing about this book—and it's not just for vegetable gardening. It's not just for ornamental gardening. It's really sort of a philosophy of soil care and of nature appreciation that can take your gardening practices to the next level. You know, I mean, it's really about learning from nature and recognizing the resources that nature is giving us that can make us better gardeners, and make our gardens healthier, and then figuring out how to use those in ways that are still aesthetically pleasing to us. 

Tasha Greer  24:21  
So, I think, you know, don't just rip out the weed, because that's never going to solve the problem. That's always just going to trigger more weeds. That's going to deprive your soil life of that carbon source. It's going to deplete your soil of nutrients. It's going to cause compaction and create drainage issues. It's just not... Sometimes you have to do it, but it's never the best answer if you can find another solution. So, the more holistically you can think about your weeding practices as part of your gardening practices, the better your soil is going to get, and you know, the fewer weeds you're going to end up with when you actually achieve that soil stability. I have areas that I've disturbed that I end up with weeds in, but the areas that I've been gardening for years, I just don't get weeds; they don't come, because they don't need to. Because I've listened to the messages of the weeds before, and I've applied, you know, ideas based on those messages that have improved the soil and stabilized the situation.

Tasha Greer  24:25  
That is so cool. And obviously, I mean, it's not something that we can get into entirely in, you know, in just a short podcast episode. So, I really hope that people will purchase your book. You know, they can get it from all the usual places. Where can people find you online, Tasha?

Tasha Greer  25:34  
You can find me at Simplestead.com. It's like a contraction of "simple" and "homestead"—simplestead. And, I'm also on Instagram @ExploreSimplestead, so you can see slice-of-life sort of photos of my garden and animals.

Deborah Niemann  25:48  
Thank you so much for joining us today!

Tasha Greer  25:50  
Thank you so much for having me.

Deborah Niemann  25:53  
And that's it for today's episode. You can find show notes at ThriftyHomesteader.com/BookChat, as well as a transcript. If you haven't already done so, be sure to subscribe so you don't miss any future episodes. You can also find Thrifty Homesteader on Facebook, Instagram, and Pinterest. See you next week on "Sustainability Book Chat." 

Transcribed by https://otter.ai