Heads-Up: It's Time to Talk "Leaf Mulching"!

[andy10917]

Where I live, the color of Fall tree foliage is beginning to show a bit, and I'm sure that farther north it's in full swing. Here they're beginning to make the change from "tired leaves" (no color change, they just fall off the trees the way they are) to leaves with color.

It's time to start talking about mulching those leaves into the lawn!! It's free (other than your time) and the single best way to get loads of free organic matter, some Phosphorus, and even a bit of Nitrogen. Heavy on the organic matter, and it's organic matter that holds the nutrients that you apply to the soil that will pay back for years.

There are a numerous threads on the site, an article, and some magazine/newspaper articles to get the conversation going. Trust me that many of the long-timers on the site do this like religion.

Here are a few links to material discussing the practice:

ATY Article on Fall Leaf Mulching

"Grounds Maintenance" Article on Leaf Mulching

Michigan State University Study on Leaf Mulching

New York Times Article on Leaf Mulching

[TimmyG]

In addition to the soil benefit, mulching leaves (and grass) is simply much more convenient than hauling them off somewhere.

[This is me]

what you do think of ground compaction due to repeatedly going over the leaves with a lawn tractor that weighs about 700lbs? With my JD X324 with mulching blade, I have to run over the leaves at least 3 times to get an acceptable size bits(1/2" or less) of leaves.

[ken-n-nancy]

Thanks for the reminder, Andy. I've just started to see a few of the fall leaves dropping on a couple parts of my lawn, some of those even with a color change.

One thing I like to remind people about is that it isn't necessary to get every single leaf off of the lawn when mulching leaves. In the fall, due to the aggressive nitrogen regimen, I find myself needing to mow pretty much every 4 days. This also turns out to be about right to keep up with the leaf mulching task. However, this also means that any leaves that get left on the lawn after mulch-mowing are going to get another chance to get mulched up in a few days.

To provide a visual of what I mean about not worrying about getting all of the leaves in each mulching, here is an example of what I do on any given mowing. My goal is basically to get about 90% of the leaves mulched up when I mow; the ones that are left will get mulched next time.

If you really want to get the grass clear of leaves, a second pass will make it look pretty good. However, I don't generally have time for that and instead just wait until the next mowing. Even if we do clear every leaf from the lawn, it will be hard to tell we bothered by about 4-6 hours afterwards anyway!

I should also mention that the below pictured leaf coverage is still pretty light. When I took these photos a few years ago, most of our big trees had nearly all their leaves still -- it's just the young trees that had been dropping leaves to this point.

Before:


After Half-Done:

[andy10917]

In Leaf Season, I get 24"+ of leaves over the season (mine plus what blows out of the woods in just minutes) and have to use the tractor for the Back Yard - many, many times. I've never had a compaction issue at all, but I'm careful not to do it when the ground is very soft after rains. You exert more lbs/sq ft standing in one spot for a minute than a tractor passing over a spot for a few seconds. Non-issue, in my opinion.

BTW, most Renovations started in mid-August will be able to handle multiple tractor passes for multiple weeks -- here's a picture of my 60-day old 2013 Renovation minutes after I completed multiple passes with the tractor.

[HoosierLawnGnome]

Got our first round of leaves this week. I have a beater riding tractor I use that doesn't cut well, but has a strong engine for fertilizer and sprayer applications - and does fine for mulching up leaves. I get leaves in the 10K along the creek mostly, and the triplex is not great at mulching.

Ran it last night!

[agn015]

Its amazing how much more convenient mulching is. I always thought we had too many leaves to mulch but that isn't even close to being true. I'm ashamed to say that we bagged our leaves the first year we moved into our home. I think my back still hurts. NEVER AGAIN! This will be my third year mulching leaves and I'm pretty sure it's my favorite part of lawn care.

I've only noticed walnut leaves on the ground so far.

This was a few years ago, about 60 bags of leaves! I'm guess no forum members live near me, because it didn't look like any were stolen

[seiyafan]

This is also a great time to feed the earthworms in your lawn.

[fun4me2]

Could someone refresh my memory about height of wheels on a push mower to create more suction.
The front should be higher correct?

With my riding tractor/mulch mower, I raise the blade to about 4" when I mulch with it.
I alternate between the 2 mowers depending on wet/dry leaves.
At this time of the year, it seems my lawn rarely completely dries out.

[ken-n-nancy]

Could someone refresh my memory about height of wheels on a push mower to create more suction. The front should be higher correct?

Honestly, I think the specifics of how the relative height of the front and back wheels affect suction / blowing out leaves when mulching / sucking in leaves for mulching varies a lot depending upon the specific mower, cutting height, blade type, and even grass type/density.

I think that in order to really figure out what works best for your mower, cut height, blades, and grass type, the best thing to do is to experiment with it a bit and see what works best for you in your specific circumstances.

For my push mower, I find that a level setting (front same as back) works best when mulching up leaves. Whether the leaves want to get sucked in or pushed out depends upon exactly where the leaf is next to the mower deck (it isn't the same for all 360 degrees around my mower) -- some areas want to suck in; others want to push out. Whether the mower is being pushed forward or pulled backwards also affects this.

Basically, I'm suggesting that you experiment a bit to see what works best in your specific case. It is likely to be different than my specific case or anybody elses, for that matter, unless they have the same mower type, same blade type, same cut height, etc...

Find out what works best for you, and do it!

[TimmyG]

Could someone refresh my memory about height of wheels on a push mower to create more suction.

Zero. I suggest keeping the wheels on the ground when mulching.

The deck, on the other hand, is best kept low(ish) for mulching. I, too, keep it level. Generally, the higher you go with the deck, the less suction (air velocity) around the lip of the deck. However, too low and you just end up pushing the leaves around (or scalping your grass). With my Honda HRX217, I see a considerably improvement in suction and mulching of leaves when I drop the deck from 3" to 2.5" for the majority of my lawn and from 2.5" to 2" for a couple small areas.

[HoosierLawnGnome]

For suction, I just make sure there isn't a huge gap between the bottom of the deck and the top of the turf. You aren't cutting anything anyways doing that

But honestly see what works best for your gear. I had a ZT that just pushed leaves out of the way if I lowered the deck too much, and too high it didn't suck them up easily. I had to go over it twice because it wasn't a good leaf mulcher basically. YMMV - try it out with your gear.

My bigger challenge is walnuts. They have to be picked up for me to run the triplex. Fortunately I have 3 kids that think it's fun to use the nut-picker-upper and do so willingly.

[andy10917]

OK, let's not turn this thread into a mower-leveling thread. Open a different thread if you'd like -- let's keep this one to helping the newer members to learn the fine art of leaf mulching, or the more-experienced to give tips.

[darkcrisis]

My yard is less than 6,000sqft with 4 large trees. There is one part of the yard that is about 750sqft that has a tree in the dead center of it. I typically relocate some of the leaves that fall from that tree to less leaf dense parts of the yard. Other than that the soil has no trouble gobbling up the mowed leaves.

I do have to mow every few days when they really start coming down to stay on top of it. It is so much easier than raking and blowing which I spend many of my childhood years doing.

[Green]

One thing I like to remind people about is that it isn't necessary to get every single leaf off of the lawn when mulching leaves. In the fall, due to the aggressive nitrogen regimen, I find myself needing to mow pretty much every 4 days. This also turns out to be about right to keep up with the leaf mulching task. However, this also means that any leaves that get left on the lawn after mulch-mowing are going to get another chance to get mulched up in a few days.

True, but leaves are a total pain when you're trying to blanket spray anything! I find myself using a blower to move them before spraying. Unfortunately even doesn't always work, since Fall can be windy! If I'm spraying something that can be used right after mowing, I strive to get all of them mulched. Another trick is mowing two days in a row (and possibly raise the HOC setting on the second day) so you don't cut on the second day, but mulch leaves...if you have to wait a day after mowing for what you are spraying.

Also, since the neighbors generally blow away or suck up and bag most of their leaves, I find myself doing multi-step mulch, blow, mow again at times to compete with them. I do manage to make it all disappear, but it sure takes a sharp blade and some conscientiousness to make it look like you bag mowed when you didn't!

[Chris LI]

I've found that mulching twice per week at the highest height that maintains a thick canopy, mulches leaves better, with less escaping from under the deck. At the beginning of leaf mulching season that is usually a 3" HOC. As the season progresses, and top growth slows, I drop HOC to 2.5". This works well with the aggressive fall N program.

Also, I switch over to a Gator blade for leaf mulching that has good suction and mulches leaves the best out of the four different blades that I own.

When it is late in the season, and the leaf pile is high, I put the side discharge chute on and obliterate 24" piles.

[llO0DQLE]

I started mulching first week of September.

2018-09-08_11-39-08

[kbgfarmer]

I started to get leaves from my multiple hickory trees weeks ago. I know hickories tend to shed early but its been crazy. As I'm establishing a new lawn I've been spending tons of time blowing leaves as my backyard hasn't grown long enough to mow yet. If the leaves continue to be a big issue I may start mulch mowing them. Better to do that than to let my grass get smothered in leaves. I have a ton of trees most of which haven't started dropping yet.

[Aviator8]

I hope this isnt too off topic. Does anyone have any issues with leaf mulching with certain tree leaves? I ask because I am doing a Reno now. There are several factors that lead to my yard going from nice and lush to crap. Me being lazy about weed control and staying on regimine was top but other factors were trees had grown creating deep shade, and high traffic in parts. One thing I think led to the slow degradation was a Pin Oak I have. I always mulched the leaves but the Pin Oak has tougher leaves. Even with multiple passes I never quite got the leaves fully chopped up. They are also slow to degrade ad they are much tougher than other leaves. I would overseed each year but those oak leaves would always mat ip eventually and creat bare spots. Do you all mulch pin oak leaves if you have them or just blow/rake them off. I want the organic material in my yard but am leaning to just blowing them off into my boarders.

[ken-n-nancy]

... trees had grown creating deep shade, and high traffic in parts.

The extra background is helpful for understanding your situation. My first comment is that deep shade and high traffic are basically an impossible combination for grass. You need to either get more light under the tree or reduce the traffic on that grass. When you say "deep shade" -- you can avoid that under a mature tree by having the tree's canopy be high enough in the air. With the mature white oaks in my lawn, the first branches are about 30' off the ground, and the shade from a single tree moves throughout the day, so that no area under the tree gets more than a couple hours of shade. If you have a complete wall or line of trees, that's a different matter, but if the branches of an isolated tree are trimmed high enough, there shouldn't be any "deep shade" under the tree. How high up are the branches of that pin oak?

You need to avoid high traffic on grass in deep shade. What is the "high traffic?" If you can't avoid the high traffic on grass in that area, you need to go to something other than grass, like mulch or rock.

One thing I think led to the slow degradation was a Pin Oak I have. I always mulched the leaves but the Pin Oak has tougher leaves.

Oak leaves are large and tough, but I haven't had particular trouble with all of the white oak leaves in my lawn. The grass is thinner in my lawn in shady areas, and it is helpful to avoid having unmulched or partially mulched leaves get piled up in bare spots and prevent growth there. However, I don't think oak tree leaves are unmulchable, by any means.