Fallen leaves in the garden will blanket the soil, slow weeds, and shelter a whole mini-wildlife community. Many native butterflies, moths, beetles, and even some queen bumble bees ride out winter tucked into leaf litter and hollow stems. When we keep some of that litter in place, we’re giving next spring’s pollinators a head start.
That's the idea behind the National Wildlife Federation "Leave the Leaves" campaign. . Each October they put out a campaign to raise awareness around the incredibly valuable habitat for wildlife and nutrients for plants that comes in the form of our yard waste.
But what if this season brought a heavy pest infestation to your garden and you don’t want to give those pests a place to shelter? That’s where a targeted cleanup comes in clutch. So, today on Just Grow Something we’re talking about how to leave the leaves strategically. I’ll give you pointers on how to keep the fallen leaf layer in your garden to benefit the bevy of butterflies, beetles, and bumblebees without giving sanctuary to the squash bugs and the scales. Let’s dig in!
Resources:
Sign up for my newsletter here: https://justgrowsomethingpodcast.com/news
Leave the Leaves Month info: https://www.nwf.org/Native-Plant-Habitats/Join-the-Movement/Seasonal-Initiatives/Leave-the-Leaves-Month
Full transcript and show notes can be found here: https://justgrowsomethingpodcast.com/episode/leave-the-leaves-strategically-ep-271
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In one year, Americans dispose of over 10 million tons of yard
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waste. That is 7% of our nation's solid
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waste. That is according to the
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National Wildlife Federation. And if you've heard the plea to
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leave the leaves this month, that has also come from the NWF.
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Each October they put out a campaign to raise awareness
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around the incredibly valuable habitat for wildlife and
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nutrients for plants that comes in the form of our yard waste.
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Wildlife like butterflies, bumblebees, fireflies,
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salamanders, they all depend on the leaf layer to get through
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the winter and have an early start in the spring.
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Those fallen leaves in the garden will also protect the
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soil and slow down weed pressure, something we as
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gardeners would be happy about. But every year at this time I
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see gardeners ask the same very valid question.
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What if I don't want the bugs? What if this season brought a
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heavy pest infestation to your garden and you don't want to
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give those pests a place to shelter?
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Yes, it's true, some yard debris can harbor those troublemakers.
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Adults of several garden pests overwinter under plant debris
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and leaf piles and reappear ready to eat and reproduce the
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moment that the temperatures rise in the spring.
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And there are other species who use this leaf litter as a layer
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of protection for their eggs. What is a gardener to do?
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That is where a targeted cleanup comes in clutch.
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So today on Just Grow Something, we're talking about how to leave
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the leaves strategically. I'll give you pointers on how to
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keep the fallen leaf layer in your garden to benefit the bevy
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of butterflies, beetles and bumblebees without giving
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sanctuary to the squash bugs and the scales.
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Let's dig in. Hey, I'm Karen and what started
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as a small backyard garden 20 years ago turned into a lifelong
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passion for growing food. Now as a market farmer and
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horticulturist, I want to help you do the same.
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On this podcast, I am your friend in the garden teaching
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evidence based techniques to help you grow your favorites and
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build confidence in your own garden space.
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So grab your garden journal and a cup of coffee and get ready to
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just grow something. This episode was inspired by
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responses to my e-mail newsletter that went out last
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Friday. I hadn't intended on making this
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a full episode, I just wanted to write about it in the
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newsletter, but I got so many positive responses and thank
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yous around the topic that I thought I would go ahead and
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make it a full episode and go into some detail here on the
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show. If you're not on my e-mail list,
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click the link in the show notes to sign up or go to
00:02:40
justgrowsomethingpodcast.com/news. So fallen leaves in our garden
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beds is going to help to blanket the soil.
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It's going to help slow down some weeds, and it's also going
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to shelter a whole mini wildlife community.
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So a lot of native butterflies, moths, beetles, even some queen
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bumblebees are going to ride out the winter tucked into that leaf
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litter and also in the hollow stems of like some of our garden
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plants. When we keep some of this litter
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in place, then all we're doing is we're helping those
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beneficials, which in turn are going to help us the next
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spring, right? So there are three things that
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we can do to manage the fallen leaves in our yards.
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Our options are to keep, move or remove.
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So what what do we keep? We want to leave a sort of
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light, breathable layer of leaves, especially in like our
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ornamental beds, beneath our shrubs, around our trees.
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And then we can sort of designate little pollinator
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corners that we can leave the leaves in as well.
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This is where the leaf litter is going to do the most ecological
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good for like the beneficials with the very least amount of
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risk to us in terms of our crops.
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So this is especially important or beneficial around native
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trees. A lot of native trees are host
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plants for caterpillars and other insects that are going to
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be looking for that leaf layer just to overwinter in.
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On the opposite side of this, it also helps like the mammals and
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the birds that enjoy the shelter of those trees but that like to
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dig through that leaf layer to forage.
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So yeah, they might be eating some of those caterpillars and
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the other beneficials, but it's also benefiting the mammals and
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the birds, right? You can also keep the leaves in
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your actual garden beds if there haven't been a ton of pest
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issues. Leaves are really, really good
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for just protecting our garden soils over the winter time from
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losses to that topsoil due to like wind or rain events.
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And it also insulates that soil for the beneficials that are in
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there. We just don't want those leaves
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to be up against any of our overwintering plants, just in
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the same way that we don't want like, our mulch pushed up
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against the bases of our plants during the gardening season
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right now. When might we want to move the
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leaves in our garden beds that were healthy this year?
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We want to just move, like I said, the the leaves away from
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the crowns of any overwintered or perennial crops.
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We also want to move them out of the pathways in our garden
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because this can actually become sort of a hazard to us.
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If you have walkways where leaves sort of pile in and then
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they get real wet and then they get matted down and then they
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get very slick. Yeah.
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You slip on those leaves once, you're going to know what I'm
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talking about. So we want them out of the
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pathways too. And then we just want to move
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those leaves either into beds that don't have as many leaves,
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right, to act as a mulch, or we can move them a few feet away
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into one of those areas under a tree or a hedge.
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You're still preserving the habitat.
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You're just relocating it out of the way of your perennial crops
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that are in those beds in landscaping.
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When you move these leaves to another designated area, they
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call that a soft landing. So we want these leaves to act
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as like a habitat patch. This could even be a corner
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somewhere too. Now, if you had significant pest
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pressure or very obvious diseases, plant diseases that
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might persist in debris that is leftover in the winter, this is
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when it's time to remove. We want to do a more thorough
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sort of sanitation procedure here.
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So the first thing is just to strip those shelters out of the
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way. We want to remove any spent
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plants that we have in the gardens.
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We want to pull out any dense leaf mats that are in those
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beds. If you're a particular pest
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overwinters under debris, this is the time to deprive them of
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that shelter just when they're getting ready to sort of settle
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in. We don't want to wait to do this
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until like after our first freeze or you know, when we
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think they might already be down in there.
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We want to kind of move it now. We don't want them to take hold.
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We want them to sort of move on right at the same time that
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we're doing this. We can rough up that bare soil.
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So you can do a really shallow tilling or you can take a broad
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fork and really vigorously sort of break up that soil or even
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take one of those hard timed Rakes and kind of scrape it back
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and forth across the soil. What we're doing here is we are
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exposing any of those adults that are hiding.
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We're also turning that soil up to expose any buried larvae or
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eggs to the elements. And we're also exposing them to
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predators. Now, we only have to do this
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where it makes sense if you've had a really bad infestation and
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that infestation, that insect tends to either overwinter as an
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adult or they tend to have larvae that buries into that top
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few inches of the soil or they lay their eggs down in there.
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This is where you want to do this.
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There is no reason to have to do this in every single bed.
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If you have not seen these, you know, predators coming in there,
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these issues, OK, I'm a firm, you know, believer of not
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disturbing that soil as infer or disturbing it as infrequently as
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possible because every time we do that, we're also sort of
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disturbing the microbiota that are in that soil.
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And we'd like to keep that as intact as possible.
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So only do this sort of turnover if you know that you've had
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these pest issues. And then once you've sort of
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cleaned it up, you've taken all the leaves off, you've pulled
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all the debris out, you've turned the soil over a little
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bit. Leave that soil bare for a few
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days, maybe up to a week, and allow the birds and the other
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predators, you know, the, the little mammals that want to come
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in and forage to come in and get rid of those pests for you.
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They can go in and they can pull the adults out.
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They can eat the larvae. They're disturbing the eggs.
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Once you've done that, left it bare for a little while, then we
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can go back through and add a thin layer of either fresh straw
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or clean leaves. If you have other areas of your
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yard that you know didn't have these infestations or they seem
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to be clean, then go ahead and bring those leaves in and you
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can put those on top as a mulch. We want to mulch in some way.
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We want a fluffy mulch to get us through the winter time.
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We don't ever want to just leave the soil exposed like that.
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So if you're pulling the disease leaves off or you're pulling the
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ones that were infested off and you're turning all this over,
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then add something back to it that is clean to act as a mulch
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over the winter time. And then, you know, instead of
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getting rid of all of those leaves, especially the ones that
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you're pulling out of from around, like the the good, you
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know, uninfested beds, we want to make that soft landing patch
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somewhere. We don't want to eliminate it,
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you know, all this habitat entirely.
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We still want the pollinators to get that winter cover.
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We just don't want it inside those beds where we potentially
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have those pests being a problem.
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And then just make sure that you are planning a rotation for the
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following year. So if you had a bed or two that
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were really, you know, attracted by the the squash bugs, the
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squash bugs are attracted to those plants and you want to
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make sure that you're moving them someplace else next year or
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maybe even not growing those plants again just to kind of
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break that that cycle of of the pests coming in.
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OK, now what do we do with the stuff that we remove that we
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can't reuse if we can't use these ones that were, you know,
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the the leaves that we're pulling off of these beds that
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were super infested with something.
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We obviously don't want to just move them someplace else in our
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yard if we think that there are, you know, adult insects
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overwintering in there. So if we're moving them out of
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our beds and we don't have space for them in other areas, or if
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we had a severe pest problem and we need to dispose of these
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leaves somehow, what do we do? That's next.
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So one of the options for your extra leaves is to compost them.
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And I mean like hot compost. OK.
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So if you're compost at home, you are going to want to aim, in
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this instance for those compost piles to remain between 131 and
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170°F for three consecutive days.
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We want to make sure that we are turning that pile so that all of
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the material is hitting the right temperature, that we're
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adding moisture when we need to in order to keep that compost
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really, really hot. And that we're using a soil
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thermometer or a compost thermometer to track that soil
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temperature and make sure we're checking at the same time every
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day for three days in a row, making sure that we're hitting
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those temperatures. That temperature range is the
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range that is used to knock down most of your plant pathogens
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and, you know, any of your weed seeds and of course any of the
00:12:00
insects in there that we don't want, right?
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The problem is that our home compost piles don't always get
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that hot and they don't always stay that hot.
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So we have to really make sure that if the goal is a hot
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compost that we are monitoring that pile.
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We are turning it when we need to.
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We're making sure we have the right ratio of, you know, Browns
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to greens and we're adding our water, we're getting that oxygen
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in there by turning it. Now, I know for a lot of us,
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composting is a very passive activity.
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We don't want to do that with these leaves.
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So if you are a passive composter and you can't maintain
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these temperatures or if you had a lot of pathogens or a very,
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very heavy pest infestation and you really don't think you can
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take care of it on your own, then skip the compost altogether
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and use your municipal green waste pickup or drop off
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facilities, right? They will commercially compost
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your yard debris. They'll take care of the issue
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for you. And in a lot of places, you can
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actually actually go back. If you're a resident and you're
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dropping off to one of these facilities, you get to go back
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and pick up a bag of finished compost in exchange for what you
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dropped off in the spring. So find some way to dispose of
00:13:12
that material that does not involve your regular garbage.
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OK, Whatever you do, please do not dispose of yard waste into
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your regular trash collection. The 3rd annual Leave the Leaves
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Month survey found that an overwhelming majority of the
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people who responded to this survey, like 72% of them,
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dispose of at least one bag of leaves in the trash.
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And 12% of those respondents are throwing away more than 10 bags
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of leaves per season, not composting them, not sending
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them to the municipal waste, literally throwing them in the
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trash. That is a tremendously high
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number, especially when we think about how damaging this is to
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the environment, not just in terms of wasted organic matter,
00:14:10
but also in terms of methane gas production.
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For organic material to decompose quickly, it needs
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access to oxygen. Decomposition at its functional
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best is an aerobic process, meaning with oxygen.
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Without that oxygen, decomposition can take decades
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for those same organic materials to breakdown.
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Landfills typically have very little oxygen flow.
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If we have organic materials like yard waste tied up in
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plastic bags and tossed into a landfill, where it is then
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surrounded by mounds of more plastic bags and then covered by
00:14:50
layers of inorganic waste, and then we bury it all, there is
00:14:55
very little oxygen. In that scenario.
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That yard waste in landfills doesn't stand a chance at
00:15:01
breaking down quickly because it doesn't have the oxygen it
00:15:04
needs. It does eventually decompose,
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but it takes much longer, and that type of decomposition is
00:15:12
called anaerobic, meaning without oxygen, anaerobic
00:15:16
decomposition produces methane gas.
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And since it takes so long for that decomposition to happen,
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the organic waste in landfills just keeps on producing that
00:15:28
methane for decades. Methane is a powerful greenhouse
00:15:32
gas that traps significantly more heat than carbon dioxide
00:15:36
over a shorter period of time and contributes to ground level
00:15:41
ozone. We don't want to contribute more
00:15:43
methane to an already growing problem for our environment.
00:15:49
So if you can't get your compost hot enough to kill off pathogens
00:15:54
or you had a very, very heavy pest infestation and you are
00:15:57
concerned about putting those leaves in a cold compost pile
00:16:01
where the insects might thrive in the spring, you can try
00:16:05
making leaf mold inside a black plastic bag.
00:16:09
I know we just talked about how bad it is to put, you know,
00:16:12
organic matter into a plastic bag, but hear me out with this
00:16:16
Leaf mold is compost, but in nature it is produced by the
00:16:21
decomposition of shaded leaves. So leaves that have fallen and
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they stay under the, the shade and they're broken down
00:16:29
primarily by fungi in a much slower, cooler manner as opposed
00:16:34
to the bacterial degradation of leaves that were used to like in
00:16:38
a hot compost pile. You know, we can duplicate this
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basically by just collecting the leaves and then we're shoving
00:16:46
them into a thick contractor grade, preferably plastic, a
00:16:51
black plastic bag. And then we wet them down just a
00:16:53
little bit and close up that bag securely.
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Now we're just going to poke a couple of holes in the side for
00:16:58
some air and then toss it in a corner somewhere.
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Just put it out of the direct sun somewhere in a corner behind
00:17:05
a building, behind your shed, next to the, the, the garden,
00:17:08
whatever, and just leave it there.
00:17:11
Leave it there, no pun intended. So what we're doing here is it's
00:17:16
it's decomposing, but it's decomposing inside that bag.
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And this could take as long as 6, as little as six months or as
00:17:24
long as two years. But at the end you are going to
00:17:27
have beautiful dark brown, earthy smelling product that can
00:17:32
be used as a mulch. It can be a soil amendment or
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you can use it as a base for like a homemade potting mix in
00:17:39
place of a peat Moss. Now you can make leaf mold
00:17:44
without the black plastic bag. So if you have an excess of
00:17:47
leaves that haven't been infested with any kind of
00:17:50
insects or it does hasn't held any, you know, pathogens from
00:17:56
diseases or anything like that, and, and you have a bunch of
00:17:58
extra, but maybe you don't have a hot compost pile or you don't
00:18:02
have a compost pile at all. You can still do this in an open
00:18:06
pile. You can do it in a bin that is
00:18:08
open and it will compost down beautifully.
00:18:11
In fact, it'll compost down a little bit more quickly than it
00:18:14
does inside the plastic bag. But if you are concerned about,
00:18:18
you know, having insect pests that might come out again the
00:18:20
next season and you don't want to have this in an open bin,
00:18:23
then that plastic bag containment is going to reduce
00:18:26
the possibility that you'll end up reinvesting your garden with
00:18:29
any pests that managed to hide in that original leaf litter.
00:18:33
Just whatever you do, please don't send your leaves to the
00:18:37
landfill. So how much leaf cover do we
00:18:43
want to leave out there in the garden?
00:18:45
Like how much is too much? We want to aim for, you know, a
00:18:49
thin quilt, not a really heavy weighted blanket.
00:18:52
We want it loose and, and, and fluffy, right?
00:18:56
So we're trying to mimic the depth of the naturally occurring
00:19:00
leaf layer to provide the optimum benefit for wildlife
00:19:05
without making it too deep. This layer is naturally going to
00:19:08
compress down and decompose overtime.
00:19:11
So around 3 to 5 inches is ideal as a loose layer, and you still
00:19:18
should be able to see the soil through in some spots.
00:19:21
OK, we do want this loose. If the the leaves mat down into
00:19:25
a soggy mess, then they can smother the crowns of any plants
00:19:29
that we have out there. If we have perennial plants,
00:19:32
it's also going to harbor slugs and there's not going to be much
00:19:35
in terms of air flow. You know, So we're, we're
00:19:38
especially concerned about this in areas where it doesn't get
00:19:41
super cold in the winter. You can have slugs and things
00:19:43
that survive down under there. So just make sure you're kind of
00:19:46
fluffing it up with a rake. And sometimes you can even just
00:19:49
do this and mix it with a coarser mulch, like a straw
00:19:52
mulch just to kind of keep it nice and airy.
00:19:57
So when should you remove? This leaf layer in the spring,
00:20:03
we obviously want to start cleaning up some of the debris
00:20:06
around our trees and such or in the garden beds before we start
00:20:09
planting, right? Well, maybe in the spring we
00:20:13
should wait as long as we can to clear out the leaf litter from
00:20:17
around our trees and our shrubs and in our ornamental gardens.
00:20:21
Ideally, we want to time this right around the time that,
00:20:25
like, people would have to start mowing their lawns regularly,
00:20:28
because by that time, the overwintering bees and the other
00:20:31
beneficials should have already emerged.
00:20:34
Now, if the leaves are in your garden beds, you may not need to
00:20:37
remove them. You know, if they've broken down
00:20:39
a bit over the winter time, you can simply just pull back the
00:20:42
leaves to plant into the soil beneath and then just add a
00:20:45
fresh layer of mulch on top. If it hasn't broken down very
00:20:49
much, or if you feel like you need to like add some nutrients
00:20:52
in the spring, there is no harm in pulling it completely off the
00:20:56
bed, doing the work that you need to do, and then putting it
00:20:59
back in place as a mulch. Leaf litter can not only be a
00:21:03
soil amendment amendment, but it is free mulch that can do double
00:21:08
duty. It can protect our pollinators
00:21:09
through the winter time and then it can protect our soil in the
00:21:12
spring. Leave the leaves is a great
00:21:15
tool, but only where it makes sense for our gardens.
00:21:17
So use it where it helps the most.
00:21:20
Under the trees, in ornamentals, along your hedges, and then as a
00:21:25
mulch over your garden beds in and around and away from your
00:21:29
perennials. And just modify it where you
00:21:31
need to. That way we keep both the
00:21:34
pollinators and the gardener happy out there.
00:21:38
Until next time, my gardening friends, keep on cultivating
00:21:40
that dream garden, and we'll talk again soon.
