putting leaves to work: shredding 101, with mike mcgrath

My compost heap in late fallFOR 17 YEARS ON PUBLIC RADIO and many before that in print, Mike McGrath has been a leading voice for organic horticulture, and a highly distinctive one. The host of the nationally syndicated public radio show You Bet Your Garden” from WHYY in Philadelphia, is—like I am—someone  who has for decades had a serious thing for gathering every shred of organic material he can get his hands on, especially leaves, and turning it all into soil-improving goodness.

Note I used the word “shred,” because on my radio show and podcast, Mike and I talked about shredding, and how the right strategy along with the best shredding device can make all the difference in making mulch and compost from those brilliant leaves you’ve been piling up.

Read along as you listen to the Nov. 23, 2015 edition of my public-radio show and podcast using the player below. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

my leaf-processing q&a with mike mcgrath



McGrath-2010-shovelQ. Congratulations, I should say first, on 17 years of “You Bet Your Garden.”

A. Isn’t it amazing? People remember me still to this day from “Organic Gardening” magazine, and I was only the editor for seven years. I was at Rodale Press, which I joined as a health writer originally, for 17 years—so I am about to surpass all of that. It’s astounding; it’s a privilege.

Q. And it’s heard in dozens of states. I have to say: It feels funny to just hear your voice instead of hear you do your show intro your show-intro voice that I am conditioned to hear first….

A. Do you want me to say “cats and kittens”? [Laughter. Note: In vintage DJ-style, Mike sometimes refers to his audience as “cats and kittens.”]

Q. How’s your leaf season been there? It has been really heavy here.

A. Exceptional. In May a year and a half ago I had to have a complete tear of my rotator cuff repaired.

Q. Ugh.

A. Oh, right, but the good experience was I hired an intern, a great young man from DelVal College, which is a wonderful horticulture school not too far from me. They exhibit every year in the Philadelphia Flower Show and they do amazing things. They have a great program.

First of all, at my age, a girl can get used to having some help around.

Q. Yes.

A. It’s really nice to put the pruners into a sturdy young man’s hands and say, “Go take care of these peach trees.”

Q. When you said you’d hired an intern, you had just said you’d had rotator-cuff surgery, and I thought, “He hired an intern to do his shoulder surgery?” [Laughter.]

A. Right, it was like going to barber college: I couldn’t afford the high-priced spread.

Q. So you’ve had a lot of leaves; manna from heaven has been falling and falling?

A. Yes. Last year he moved on of course at the end of the season, and by then I was still kind of tender. So I didn’t get as many leaves as I wanted to, and I felt inadequate over the winter.  But this is a year later, and I am 18 months out from the surgery. It’s like if you go through a red light accidentally, you stop twice at the next one.

Q. Exactly. Are you all done, or are you still at it out there?

A. I’m all done in that I’ve captured every leaf that has fallen on my personal landscape. Now the National Wildlife Federation is yelling at everybody to let your leaves stay where they are; to smother your lawn!

Q. Oh please; that’s ridiculous.

A. I think one of the reasons they’re doing it: Don’t forget, it’s the National Wildlife Federation. All they said was leave your leaves where they are, because they’ll remineralize the soil and they’ll give overwinter places for frogs and toads and all the little creatures that we love. But down deep in their heart, we know they hate lawns—and if people leave whole leaves laying on their lawn they won’t have a lawn, and that when the NWF will try to convince them to put in a meadow or something.

Q. It’s kind of like putting cardboard on your lawn [laughter] to smother it.

A. God’s cardboard.

Q. Even if it’s late, and people have already done their leaves, everyone has a stiff shoulder or aching back, so it’s a good time while those aches are fresh to make resolutions for a more efficient tactical approach next year. Let’s go through your strategy for leaf management in fall. Shall we start with on the lawn, as you were just mentioning with the NWF idea.

A. I learned so much from my editors and the readers of “Organic Gardening” magazine. One of the first thing I learned was like on a level of Frankenstein and Tonto: “Whole leaves, bad; shredded leaves good, good.”

Really, whole leaves as you know, once they get wet and cold, do a good imitation of a tarp. But once you shred them up, they can do almost anything. If they’re on your lawn, just run them over with a mulching lawn mower, and instead of killing your lawn they’ll feed your lawn with all those pulverized leaves.

If you don’t treat your lawn with any herbicides, you could also use a bagging mower, and that’s like super-easy—the lowest-hanging fruit. Use the lawn mower as sort of a leaf vacuum. If your lawn isn’t treated, you’ll get a little bit of Nitrogen-rich grass clippings in there, and what you’ve got is the perfect starter compost. It’s your game to lose at that point.

Q. There was a great tip recently on “You Bet Your Garden.” Say you have all these shredded leaves piled up in your compost heap, it suggested to inoculate them with some finished compost to get them going.

A. That was spurred by a listener, who was kind of happy and sad at the same time. He had done all the right things: shredded all the leaves, mixed in lots of coffee grounds to provide a source of Nitrogen to move the composting process along.  He’d even turned the compost—he’s a younger man than I.

Q. [Laughter.]

A. Finally, at the end of the summer, all of his compost was completely finished. But it’s sitting in his compost bins as his leaves are coming down, and he goes, “What now?” I was happy to explain to him that that’s the cold, hard reality of composting in the Northeast.

If we get a cold winter, the laws of physics will not suspend themselves for your personal gratification. You’ll get some compost, but not a ton of finished compost in the spring, but most of it unless you’re being really aggressive, it’s going to take about nine months. It’s like having a baby.

I had the same experience. I filled up all my raised beds that weren’t filled to the top that needed a nice application of compost, and then I still had a lot left over.

I remembered the old advice that there is no better was to get a compost pile cooking than to put some finished compost in with it. It’s almost like starting a worm bin and adding the worms. Duh.

Q. Because instead of the worms, which are big, there are these microbes that we can’t see that are going to do the gobbling up.

A. Exactly. Throw them into a pile of shredded leaves with some coffee grounds, and it’s like going to the prom. They’re going to stay out late and make whoopee.

Q. As my old boss Martha Stewart used to say: “It’s a good thing.”

A. It’s a totally good thing.

Q. First, how big is the area you’re managing, what’s your tool of choice for shredding?  I’m like two and a half acres surrounded by mature forest, so it’s leaf heaven.

A. I have about an acre and a half, half of which is mature forest—forget the surrounded part.

Q. Oh, boy.

A. In retrospect, I’d give this advice to any prospective homeowner: If you’re really interested in gardening, don’t buy Snow White’s old house. It’s really good when the chipmunks and birds come and help you wash the dishes and stuff, but heavy tree cover is not the best for growing tomatoes.

Q. I’ve been in my garden about 30 years, and even the things I planted that were maybe 6 feet tall at the time are now mature: much bigger and making more shade. So I do have less lawn that I did, and more trees even in the garden proper.

So yours is a big space. I confess, I don’t have a leaf blower or shredder.

A. You’ve got to—you’ve got to ask Santa.

fall-main-callout-home1Q. I don’t know if Santa stops on my dirt road, but I have Cyclone Rake envy and a neighbor with a tractor and a Cyclone Rake, and we’ve made a deal so he drives it through my place.

If people don’t know what they are, it’s a big collapsible box-like trailer with a vacuum and shredder and hooks onto your tractor. It sucks the leave up and shreds them and you can empty them into your heap. So now I have 83 million pounds of shredded leaves, thanks to Herb, my 83-year-old beloved neighbor and best friend.

But let’s get real: I need a shredder myself. What shall I do?

A. Back in the 90s, when I was the editor of “Organic Gardening,” our tools section was very popular. Especially back then, people were really going back to the land, and buying a lot of tillers and little tractors, so reviews of garden machinery were hugely popular.

My equipment editor at the time was Scott Meyer, who became the  editor after I left, and he got everybody on the staff a different electric blower-vac. One person got the Flowtron thing that you put on top of a trash can that has string trimmer that you put the leaves into.

We tested about 10 different ways to shred your leaves, and I got a Black & Decker weed eater or leaf eater kind of thing. It worked perfectly. It was corded, so you were stuck with 100 feet; 100 feet tends to be pretty good, but you get tired of lugging the cord around after awhile. But there is no bending over. I don’t understand leaf blowers.

Q. I don’t either; I see them at people’s places near me and they’re just pushing leaves around and I think, “What good is that?” What’s the point?

A. You make a ton of noise. You cause all this debris to fly up into the air that you’re breathing in. And when you’re done the leaves are still on the ground. It makes as much sense as putting a screen door on a submarine, or taking pork chops to a Seder. It’s not working.

Q. [Laughter.] We’re getting the Mike McGrath-isms; we’re getting them, folks. That’s a multiple Mike McGrath-ism that we just got there.

A. The nice thing about these blowers that have the reverse setting and the collection bag: You pass over the leaves once. You get them off the area you don’t want them. They go into a bag, and you can put them into a container to save for next year or put them into your compost bin.

I know some people who suck the whole leaves out of their flower beds, then just drop the whole bag of shredded leaves back into the flower beds. From potentially destructive plant killer to plant-feeding mulch in one step.

Q. Right.

A. And you never bend over.

Q. And you say, “potentially destructive plant killer;” same thing you were saying about the lawn. I’m obsessed with raking leaves out of my beds, and readers write and ask, “Why do you rake your leaves out? They’re so great to leave.” And I’m like, “No.” Voles and mice and everybody just has a party under there. I lift off matted leaves where they have blown back in over the winter, and inevitably there are animal tunnels…

A. …and mold.

Q. And molds. And some of the earliest bulbs…

A. …are totally smothered. There’s nothing sadder.

Q. They’re all distorted.

A. There’s nothing sadder than raking up a patch of frozen leaves in February and going, “Oh my God, that’s where the glory-of-the-snow was.”

Q. Exactly. So at least take them off for a minute and shred them and put them back if you like, but don’t leave them matted there.

Fallen leaves under copper beechA. What people don’t understand is that trees kind of drop their leaves for two reasons. One is to close up for winter, and retain moisture, and not have that weight that can break the tree during a snowstorm.  The other purpose—and maybe there are three purposes, because once those leaves fall to the ground and disintegrate they’ll feed the tree—but one of the big purposes is to beat up all the children on the forest floor.

Q. [Laughter.]

A. Those leaves suppress the competition of all those smaller plants, and make sure that the trees are the big bullies in the schoolyard.

Q. So the tree self-mulches, so to speak.

A. That’s why it’s often very easy to walk through dense woods.

Q. So we’re going to shred them on the lawn in place, or shred them and put them in a heap and inoculate it with some finished compost. And we’re going to take them off our beds, even if we put them right back shredded again.

A. Take them off; put them back on. It’s like Army work.

Q. Now this machine that you’re wanting me to get for Christmas—or that you’re sending me for Christmas, thank you so much.

A. Oh you’re so welcome. [Laughter.]

61Ha-Cq2u7L._SX522_Q. What does it look like? Do they all shred, or collect the stuff, or have bags on the back?

A. There are some blowers than just blow, so you want to make sure you get one that says, “blower-vac” or “reverse setting.” It will always say that on the box; you’ll see a picture of the collection bag as well. One nice thing about these machines, is that they have improved over the years. The one I got in the 90s lasted me 10 years.

Q. That’s great.

A. Oh, yeah. The plastic casing melted from me overheating the thing, sucking up wet leaves, and it still refused to die. Finally I replaced it; I’m only on my second one, and I’ve gone through three cars in this time.

A couple of years ago, which of course turns out to be four years ago when I looked at the receipts, I bought a Toro, which retails now for about $100. It’s one of the higher-end machines, but it has a metal impeller—the giant wheel inside that shreds the leaves. It works really well; it’s probably on its fifth season. You can get a really decent one for like $60.

But I had an inspiration, and I called Hammacher Schlemmer. The high-end, best-of-everything catalog—”Oh,I want this and I want that.”  I had been looking at their best ever in the universe rechargeable blower-vac for a season now. I called them up and asked them if they ever lend out equipment for testing, and they said yes. So I have a spaceship—I got a shiny new toy. No cord; it’s got this big 40-volt battery you slide in. It has the same collection bag and everything like that. This monster is like a Cadillac; it’s making the smallest particles you’ve ever seen.

from hammacher schlemmerQ. Is it quieter?

A. I think it’s about the same. I’m deaf anyway because I used to work in the rock-and-roll business.

The battery only lasts about 10 minutes, on double full turbo power, which is what they recommend. It has a lot of settings but it’s like “Spinal Tap,” you turn it up to 11, if you’re going to be sucking up and shredding leaves.

It only does two collection bags full, which is absolutely fine for me. As I get older I constantly remind myself to keep changing my work.

Q. I think that’s good advice for any age.

A. I do 20 minutes of pruning, 20 minutes of digging, 20 minutes of weeding. So I’ll bring the battery back inside, and the battery recharges completely in 90 minutes.  If I do my first run at 10 o’clock, I’ll do like three sets, and I get it done so much faster because I’m not dragging this heavy, 100-foot extension cord behind me. I’m really going to cry when I have to send it back.

Q. Maybe you’ll buy yourself one for Christmas.

You answer listener calls on your show as I did for years when I hosted the Martha Stewart Sirius Radio channel garden show in my old life, and I get oodles of them on my website, so I want to take our last few minutes to ask you this, and compare notes:

What are the most popular topics year after year? I’m always asked, “Why didn’t my (blank) bloom?” and the blank is often lilac, rose or hydrangea.

A. That’s a big one, and hydrangeas have been really pissy these last few years with cold winters. I would add, “I just pruned my (fill in the blank). Did I do the right thing?” [Laughter.] What are you going to tell them?

Q. “Better luck next time?”

A. The other one is “Deer ate my car. They finished off all the plants, and ate the car, and they’re eyeing the children on their way to the school bus now.”

Q. What about slugs? Is that a big one?

A. It used to be, back when I was editor at OG, it was like an obsession. Climate change, the power company and Hurricane Sandy have cost me a lot of trees in the area that was previously shading my garden, so I don’t see many slugs any more.

And I don’t think people realize that’s what the problem is. They’ll see like praying mantis or a stick insect in their garden, and say, “All my lettuce was eaten to the ground. Spiders and praying mantis are doing it—what can I do?”

And I say, “Go out tonight around 11 o’clock and take a look at what’s eating your lettuce to the ground.”

Q. So do you want to say your show signoff before I say mine?

A. Do I have a signoff?

Q. You always sound so energetic when you say goodbye at the end of a program.

A. Really what I do, really where all that came from was listening to AM top-40 radio growing up in Philadelphia. The DJs were always spinning the hot plaques with the hot wax, and in the groove, and coming up with these pet names for everybody. That’s where “cats and kittens” came from; it’s where everything came from. It’s from boss jocks of the late 50s and early 60s.

Q. Good role models, I think. Thank you, Mike.


listen to mike mcgrath’s ‘you bet your garden’

prefer the podcast version of the show?

MY WEEKLY public-radio show, rated a “top-5 garden podcast” by “The Guardian” newspaper in the UK, began its seventh year in March 2016. In 2016, the show won three silver medals for excellence from the Garden Writers Association. It’s produced at Robin Hood Radio, the smallest NPR station in the nation. Listen locally in the Hudson Valley (NY)-Berkshires (MA)-Litchfield Hills (CT) Mondays at 8:30 AM Eastern, rerun at 8:30 Saturdays. Or play the Nov. 23, 2015 show using the player near the top of this transcript. You can subscribe to all future editions on iTunes or Stitcher (and browse my archive of podcasts here).

  1. Lots of good leaf mulching info at leleny.org — the home site of the “Love ‘em and Leave ‘em” initiative in Westchester County, NY.

    Topics organized from the perspective of homeowner, landscaper and municipality. Educational materials including videos and a toolbox of public domain outreach materials. Help bring leaf mulching awareness to your town / community.

    Read about Cornell University’s ongoing research into the impacts of leaf mulching in lawn health, as well.

  2. Mel says:

    Great article! I am curious, the link to the Toro has several sizes, 160 mph up to 250. Which one did Mike recommend? I am trying to find the weight on each as my arm gets tired lugging around mine. Thanks!

  3. Shellee Morrison says:

    I have the WorkX leaf vac. My problem is that when I vacuum in the beds which have been mulched, the wood mulch gets caught in in the shredder and jams the machine. Happens about every 90 seconds seems like. Do I need something with a higher HP?

  4. Dianne says:

    I have the Toro blower vac like in the picture. It’s about 7 years old and still going. I don’t have a lot of trees, so it shreds up the leaves I have quite easily. I add egg shells and coffee grounds to the leaves. Great compost. I don’t use the blower for leaves, only for cleaning off the sidewalk and patio. I would definitely recommend for anyone who doesn’t have piles and piles of leaves.

  5. Lynne says:

    Over the years we have acquired one of everything for shredding leaves from a Craftsman gas powered $1000 unit to a $100 shredder that works like a weedwacker over a barrel – and also a weedwacker in an actual barrel. I’ve come to favor a 2-step process for the lawn. First I mow the leaves on the lawn and collect them in the mower bag. Then I deposit them into an empty trash barrel and vacuum them out, using the electric blower on reverse. The blower is hooked up to a device (Worx, I think) that directs the now twice shredded leaves into yet another barrel which gets dumped into a leaf-only compost pile to be used as mulch. There are plenty of worms but very limited weed seeds in this pile. The beds get racked out onto the lawn or driveway where the leaves get processed in the same way – and then I remulch with about half the volume of the leaves that were removed. This process has done a pretty good job building up the builder fill to create decent woodland soil. I do wish the blower/vac were more powerful and could process more leaves more quickly – maybe I just need an intern and a second blower…..

  6. Jack says:


    I have a Toro blower-vac and found it cumbersome when vacuuming leaves. This year I got a little smarter and used the blower to pile the leaves. Then I set up the Toro to vacuum the leaves but instead of strapping the vacuum on me I laid the vacuum on the ground and raked the leaves into the collector tube. This worked well for me and was less tiring.

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