# How long for mulched leaves to decompose



## Jay20nj (Jul 25, 2018)

I normally bag the leaves as i hate the look of them but since i just did a reno and i'm fertilizing more frequently i dont want to suck up the fert. This would be applicable to the nitrogen blitz as well. So I'm mulching them this year. They are in about 1/4 to 1/2 inch pieces. How long do mulched leaves take to decompose?


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## Justmatson (Apr 4, 2020)

Jay20nj said:


> I normally bag the leaves as i hate the look of them but since i just did a reno and i'm fertilizing more frequently i dont want to suck up the fert. This would be applicable to the nitrogen blitz as well. So I'm mulching them this year. They are in about 1/4 to 1/2 inch pieces. How long do mulched leaves take to decompose?


I mulch mine all the time. Run them over a few times.
It doesn't take long to decompose.

Are you not mulching your grass clippings?

Its much easier and more beneficial just to mulch everything, grass and leaves.


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## Jay20nj (Jul 25, 2018)

I was not previously mulching before my reno as i had a lot of weeds which means weed seeds. Now I plan to mulch. When i cut with the gm1000 i dont use the catcher because i cant get as close to things


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## Justmatson (Apr 4, 2020)

Jay20nj said:


> I was not previously mulching before my reno as i had a lot of weeds which means weed seeds. Now I plan to mulch. When i cut with the gm1000 i dont use the catcher because i cant get as close to things


I dont have a reel so I can't give advice on mulching leaves with it. 
I probably wouldn't. Just use a rotary mower with a good sharp mulching blade.

After a week or two you won't even notice them.


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## Jay20nj (Jul 25, 2018)

I mulch with my rotary. Reel wont mulch or even pick them up


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## ScottW (Sep 16, 2019)

I've gone to mulching all of my leaves in the fall. Used to bin/bag them for the county to haul away, until I saw the light.
My soil tests in years past showed about 4% organic matter.
Last fall I mulched all my leaves. This spring my soil OM was over 7% and CEC had increased from 10-ish to about 14. Accepting that there will be some test variability and sampling differences year-to-year, this at least still looks headed in a good direction.

My back yard gets inundated with leaves, but my front yard hardly gets any. This past weekend I raked & blew multiple loads of leaves in the back onto a blue tarp, dragged them to the front yard and distributed them all around, and then mulch mowed them in.

The bulk of the leaf confetti will disappear from view in about a week if you're just casually looking at the lawn as a passerby would, especially if you get some rain to help carry it down. On closer inspection you'll see bits for a while longer, maybe a month or more but they'll be well down towards the soil. IMO any temporary unsightliness is probably worth it for the longer term benefits to the soil. Other methods of adding organic matter are more expensive and laborious compared to mulch mowing all those free leaves.


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## Ngilbe36 (Jul 23, 2020)

Agree with the comment above from ScottW. My only issue is I have 3 30+ year old maples in my front yard which is about 3k sq/ft. So That produces a LOT of leaves for the area. Pretty much every other mow, I will bag them and dump that in my back yard (15k with less tree cover) and mulch them back there. Leaves = OM and free nitrogen. Mulch on friend.


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## badtlc (Aug 22, 2019)

Jay20nj said:


> I normally bag the leaves as i hate the look of them but since i just did a reno and i'm fertilizing more frequently i dont want to suck up the fert. This would be applicable to the nitrogen blitz as well. So I'm mulching them this year. They are in about 1/4 to 1/2 inch pieces. How long do mulched leaves take to decompose?


When mulched well you won't see them long at all. Maybe a few weeks.


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## Jersey_diy (Sep 5, 2020)

It all depends on how much your leaf density is. I have abou 15k of turf, 10 or so large to medium oaks. I use to mulch with my ride on mower and saw that it was just too much leaves being left on the turf. I promise you if you have a lot of oaks and each weekend you have enough leaves that you can't step anywhere without stepping on a leaf that if you mulch each weekend you will negatively affect the turf. If your leaves are few and far between then you will be ok. You don't want to be mulching complete cover each weekend. I have found that it is better for the turf to just leaf blow them to a tree line. Keeps the turf free and clear and you don't put to much wear on the grass.


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## Miggity (Apr 25, 2018)

One thing that works well for me to get as many leaves into the lawn without overdoing it is to do a mulching cut all over and then mulch the heavy leaf areas once again. I then switch to bagging and raise my deck one notch and go over the entire lawn again to pick up any excess. The raised deck should ensure your fert stays put.


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## Thejarrod (Aug 5, 2018)

I have the same experience as @Jersey_diy . I'm mowing them 2x weekly and My oaks put down tooo many leaves. 
My strat is to take the lawn sweeper around to grab maybe 30-50%. Then mulch the rest. It's pretty obvious when there are too many.


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## Deadlawn (Sep 8, 2020)

It depends on the types of leaves. Maples, birches, cherries and other fruit trees decompose pretty quickly. Oaks takes longer to decompose.

On my own lot, the red maples come down first and I mulch them. The oak leaves are harder for the mower to chop into little pieces, so I just remove and compost them separately.


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## Green (Dec 24, 2017)

I'm not a fan of overloading the lawn with leaves later in the season (from November on or so here). I've done it in the past...mulched so many in that the lawn was full of leaf mulch between the grass blades. But I think it contributes to turf damage and maybe even snow mold if it's overdone. One year in particular, it was so bad that I ended up raking some of the leaf pieces out in January. The rest didn't break down until April. Trying not to have a repeat of that.


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## Jeff_MI84 (Sep 28, 2020)

I was told it's best to take as many leaves off the lawn as possible, especially at the end of the cutting season. Everyday after work I get my leaf vacuum out and get up as much as I can before mowing. Apparently I'm the only one on my street who does it.


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## Jersey_diy (Sep 5, 2020)

I don't know if you need to do it everyday, but I agree it is best to get them off the lawn, and any unsightly signs too, lol


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## Lawn Noob (Jul 26, 2020)

Jersey_diy said:


> I don't know if you need to do it everyday, but I agree it is best to get them off the lawn, and any unsightly signs too, lol


I dig the sign.


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## JERSEY (Sep 9, 2018)

I LIKE the sign too!!!!


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## StanMI (Aug 18, 2020)

Love that sign


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## Thejarrod (Aug 5, 2018)

:x NO :x NO :x NO :x NO :x NO :x NO :x 
I dont want politics to invade my lawncare content!


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## Jersey_diy (Sep 5, 2020)

Don't worry it was just a joke.. we are all friends here


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## Thejarrod (Aug 5, 2018)

Jersey_diy said:


> Don't worry it was just a joke.. we are all friends here


 :thumbup:


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## Captquin (Aug 22, 2019)

Agree on leaves. Always wondered if the same holds true for pine needles.

I typically take those and use for much in the beds. Would it be better to mulch those for the soil as well?


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## dfw_pilot (Jan 28, 2017)

Thejarrod said:


> :x NO :x NO :x NO :x NO :x NO :x NO :x
> I dont want politics to invade my lawncare content!


We try to keep content like threads to a political minimum. The small stuff like this is usually best just overlooked. If it isn't, the offended usually ends up drawing more attention than the offendee, and we try to not be too heavy handed here at TLF.


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## JERSEY (Sep 9, 2018)

Captquin said:


> Agree on leaves. Always wondered if the same holds true for pine needles.
> 
> I typically take those and use for much in the beds. Would it be better to mulch those for the soil as well?


Good question.

I try to much them when its light, but right now there was 6 trailer loads dropped on my property from those winds. They dont break down like other leaves.
I put them in the stream bed.

Like to hear other opinions on pine needles


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## Captquin (Aug 22, 2019)

Same here for the most part. I rake as best I can and put in the flower beds. Mulch what's left with the mower. Assumption is that if they are good mulch for smothering grass and weeds in the flower bed, they probably do the same in the yard.

I frame it in my mind that never have to buy mulch.


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## elgrow (Mar 30, 2020)

As someone with large oak trees that put out a lot of leaves has anyone heard of the leaves actually increasing the acidity in your soil?

I feel like I've heard it somewhere as one of it's allelopathic measures of keeping other plants out of it's root zone, but can't remember for the life of me if that's true.

I usually blow mine off into the mulch beds and then will just mulch the remaining few in the yard that fall while mowing or won't come out with the leaf blower.


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## Jersey_diy (Sep 5, 2020)

It is very typical to have low ph of you have oaks... Pines... That's my situation, and I have clay soil. Like treatments are a part of life for me


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## ABC123 (Jul 14, 2017)

Promoting the microbial population with some molasses and feeding it N/urea will help the decomposing.


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## Deadlawn (Sep 8, 2020)

elgrow said:


> As someone with large oak trees that put out a lot of leaves has anyone heard of the leaves actually increasing the acidity in your soil?
> 
> I feel like I've heard it somewhere as one of it's allelopathic measures of keeping other plants out of it's root zone, but can't remember for the life of me if that's true.
> 
> I usually blow mine off into the mulch beds and then will just mulch the remaining few in the yard that fall while mowing or won't come out with the leaf blower.


Oaks are not allelopathic. Plenty of types of plants can grow in the root zone of oaks. Black walnuts and Norway maples ARE allelopathic.


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## AndyS (Jun 13, 2020)

Jersey_diy said:


> It is very typical to have low ph of you have oaks... Pines... That's my situation, and I have clay soil. Like treatments are a part of life for me


I didn't know this... though I've never done a soil test, so I can hardly complain :lol:

I have pin oaks and clay soil, so I should get around to using that Yard Mastery soil test that my wife complains is cluttering up the kitchen :thumbup:


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## Jersey_diy (Sep 5, 2020)

Soil test can be your friend.. that is for sure.. I would do it in the early spring before any treatments


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## Minnesooota (Mar 26, 2020)

Jay20nj said:


> I mulch with my rotary. Reel wont mulch or even pick them up


My reel laughs out loud at such an idea.


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## Chris LI (Oct 26, 2018)

Thinking about this subject (generally speaking) at the end of the season, so I searched up leaf mulching.

I finally changed up my leaf mulching plan, and am very happy with the results. As a huge leaf mulcher, I usually mulch most leaves and only bag at the very end of the season (except for the stray bag mow, on a light leaf day, or after mulching them for a clean look). I'm a huge OM boosting fan by leaf mulching, but I like a clean look, too. I deal with a heavy leaf supply for the season. When the leaf cover is very heavy, I switch from mulching to side discharging, which turns them into powder (of course with a Gator blade). In the past, I have mulched too late into the season, and had leaf mulch embedded in the turf.

This year, I didn't do any "clean up" bag mows early in the season as far as I can remember (my journal will call me a liar, if that's not the truth...lol), so I could maximize my OM, knowing that I would cease mulching earlier. The idea was to get approximately the same amount of OM down, without having excess mulch at the end of the season. To keep somewhat of a clean look during the early mulching season, I started side discharging earlier and made even more multiple passes than usual to turn them into dust. This way I got a much down as early as possible when the soil temps were higher and the microbes would quickly digest them. Then, I did my end of season blowout of the beds a little earlier, so I could side discharge them to get the OM pulverized. After that, I abruptly ended mulching and strictly bagged, so I would not have any undigested leaves in the lawn. I believe this helped with turf density, which was my biggest concern, not necessarily aesthetics (although it is a nice benefit). I tried to time this before the cold snap hit, and we had a warmer fall than usual, so I don't know if I will be able to duplicate this in the future. Most undigested mulch was picked up, along with stray twigs and junk, with my Snapper Hi-Vac. I am very happy with the results. I'm curious if anyone has tried anything similar.

FWIW, I have a large Norway maple and some Red maples in the backyard, and a lot of Red oaks across the street in the front (with a white pine in the neighbor's yard behind us). As others have mentioned, the Norway maple is alleopathic and the Red oaks and pine are acidic. All are worth mulching. The pine needles really only get picked up with side discharging or bagging.


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## Deadlawn (Sep 8, 2020)

Chris LI said:


> FWIW, I have a large Norway maple and some Red maples in the backyard, and a lot of Red oaks across the street in the front (with a white pine in the neighbor's yard behind us). As others have mentioned, the Norway maple is alleopathic and the Red oaks and pine are acidic. All are worth mulching. The pine needles really only get picked up with side discharging or bagging.


Red maple leaves make excellent mulch as they are small and decompose quickly. Oaks in general take longer to decompose. Some oak leaves mulched are OK, but a lot will build up and give you that "unclean" look in the lawn you speak of. They would be great in the garden beds though. Your plan of mulching early, cleaning up later works well because the red maples are usually the earliest to fall, then come the oaks. I believe the toxins in Norway maples is mainly in the roots, not the leaves. When I lived in NJ, I had a large Norway maple which I mulched leaves from and put them around my plum trees. The plum trees seemed to love them.

As you say, oak leaves and pine needles are acidic, but nothing that lime can't reverse. And they won't change the pH in the lawn much unless they are piled high enough to smother the lawn anyway. If you have rhododendrons, azaleas, blueberries or other acid loving plants, those *love, love, love* oak leaves and pine needles.


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## Chris LI (Oct 26, 2018)

Deadlawn said:


> Chris LI said:
> 
> 
> > FWIW, I have a large Norway maple and some Red maples in the backyard, and a lot of Red oaks across the street in the front (with a white pine in the neighbor's yard behind us). As others have mentioned, the Norway maple is alleopathic and the Red oaks and pine are acidic. All are worth mulching. The pine needles really only get picked up with side discharging or bagging.
> ...


^+1
EXACTLY! 
All the bagged leaves go into my vegetable garden and compost pile. In the garden, I make piles according to particle size. After I breakdown the garden (still on my to-do list), I place the smallest size on the bottom to the largest on the top, with saving any whole leaves available for the very top. This enhances breakdown at the soil level and keeps a solid mulch barrier on top. When I plant, I only move enough mulch to plant the vegetables, so I don't disturb the barrier. This works very well. FYI-I use organic granular fertilizers at the time of planting and supplement periodically with organic liquids alternating between foliar sprays and soil drenches.

You're dead on with the timing/order of the leaf drop, and funny enough, I document it in my journal. The Red maples are in the NE quadrant, so even though they drop the earliest, the soil temp is the coldest (I've taken readings in the past), resulting in slower microbial activity. I will have too much of a buildup of leaf mulch for that reason and due to three of them in close proximity to one another, so I've learned to start bagging there a little earlier (some oaks wind up blowing into that area to complicate the situation, too). Those trees also drop most of their leaves very quickly. Often, the tree is practically bare within a week of the first leaf to drop. Thanks for the reminder about the azaleas, I should save some oak leaf mulch for them.

You're definitely correct on the Norway maple root alleopathy, as I've studied and witnessed it.

Also, on the subject of maple alleopathy, there was a study (university in the midwest, I think) that documented maple leaf mulch inhibited weed germination (broadleaf, I think). I believe they didn't distinguish what type of maples. If I recall, they included oaks in the study, but they showed no statistical difference in inhibiting weed germination. If I can find the link, I'll post it.

Funny thing about mulching leaves, I overdid it the first or second year, because I REALLY got into it, and mulched nearly everything (probably the equivalent of 100-200 grass catcherfuls). I ran short for the garden and had intense weed pressure the following spring. I learned from that one!


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## Green (Dec 24, 2017)

Yesterday, I mulched leaves on a lawn that didn't get leaf-mulched for three weeks prior, and there were very few down at that time. So I mulched in a season's worth of leaves (majority Maple) on the very last mow of the year!


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## Chris LI (Oct 26, 2018)

@Deadlawn
I found the pdf of the study that I referenced above. I had it saved in my phone but couldn't find a link to post, so I'll post a screenshot with the title. Briefly, it was a study done at MSU with red maples, silver maples, sugar maples and red oaks. The maples did the best to suppress dandelions, but the oak leaf mulch helped a little.

You should be able to Google the title, or a portion of it to download the whole study.


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## Deadlawn (Sep 8, 2020)

Chris LI said:


> @Deadlawn
> I found the pdf of the study that I referenced above. I had it saved in my phone but couldn't find a link to post, so I'll post a screenshot with the title. Briefly, it was a study done at MSU with red maples, silver maples, sugar maples and red oaks. The maples did the best to suppress dandelions, but the oak leaf mulch helped a little.
> 
> You should be able to Google the title, or a portion of it to download the whole study.


This makes sense, but it could be for different reasons. In Paul Tukey's "Organic Lawn Care Manual", he mentions that weeds should be considered messengers of problems with soil conditions. The idea is to fix the problem, not kill the messenger. He gives a whole chapter to common lawn weeds and the soil indications for each one. According to him, dandelions like low calcium and low pH.

Where am I going with this? Well it stands to reason that adding some leaf mulch adds certain nutrients. That might not be the whole story and it certainly doesn't explain oak leaves helping control dandelions as oak leaves will lower the pH. It could be that the leaf mulch helped the grass grow thicker therefore preventing weed seeds from germinating beneath the canopy of the thick "turf jungle". Not to mention the leaf mulch residue itself preventing even more light from reaching the bare ground where the seeds are.


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