I am going to be a bit direct here, but I think you need to hear it. And I need to preface what I’m about to write by stating that I am not being melodramatic, hyperbolic, or exaggerating. Here me now – adding leaf mulch is the single best thing you can do to your garden. It’s better than just adding fertilizer, it takes less effort than composting, it’s free, and it naturally will suppress weeds for the next entire growing season. That’s it. Those are the primary reasons.
I’ve been using leaves on my vegetable garden for five solid years now, and have documented the improvements to my soil and garden yields each year with a YouTube video. See the video results here (2020, 2021, 2022, 2023, and 2024) and as an article/case study here. But, in this article I’m going to tell you how to use leaf mulch, as I’ve learned a few tricks to save time, how to keep them in place, and how to plant seeds the following year with leaf mulch.
How to apply leaf mulch
Leaf mulch, is, well, just that – it is when we use Autumn leaves as a mulch in a garden or flower bed. To apply a leaf mulch, simply rake your leaves and transport them to a garden and/or flower bed. Pile them up several layers thick, and then spread them around with a rake to try to get it somewhat level.
Over the following growing season, these leaves will look similar to traditional mulches and serve the same purpose – namely as a layer of organic matter that will prevent weeds and slowly decompose, while helping to retain moisture. The nutrients contained in those decaying leaves will become part of your garden. See here for more detail on the many benefits of leaf mulch.
Related – See my 5-year garden soil transformation using leaf mulch
How thick should your leaf mulch be?
For thickness, I like to make my leaf mulch at least 6″ thick (15cm) in the fall. This is a thick enough layer to suppress weeds for the following growing season. Now, this isn’t loose leaves that can blow around, but ones that have been bagged. So, there is some amount of compaction. However, over the winter months this layer will become more and more compacted, shrinking significantly, by 50% or so.
On my vegetable garden, I will make the leaf mulch as thick as I can. I’ve had it as thick as 12″ a couple years in a row. In general the thicker the layer you apply, the better it will be for your soil as well as suppressing weeds.
Should you mow or till the leaves into the soil?
In short, no. You do not need to mow up the leaves. I mowed up most of my leaf mulch back in 2021, thinking that it would break down faster and my plants would benefit sooner. But, in reality, it all seemed to persist the same as the other years. The leaf mulch persisted throughout the growing season and did not seem to decompose any faster. The main reason for this is most likely that it is fungi and insects/worms that will decompose the leaves, not bacteria (we aren’t composting them). But, take it from my experience- you do not need to mow the leaves!
In regards to tilling the leaves into the soil….you don’t need to do that either. First, each year the topsoil and organic matter from the leaf mulch will penetrate deeper into the soil from natural processes as well as insect/worm castings. Eventually it will reach depths much deeper than what conventional tillers can go. Second, by tilling the leaves into the soil, you will be losing the benefit of having a weed barrier. And I can truly tell you, with a proper layer of leaf mulch you will not be pulling many weeds.
What you are looking at in the picture is the depth of my ‘black’ crumbly soil after five years of leaf mulch. It is about 10-11″ deep, and this is starting from orange, inorganic soil. I just pile up the leaf mulch, and have never used a tiller in my rocky Pennsylvania soil.
Tips to stop leaf mulch from blowing away
If you are just raking up your own leaves from your yard and piling them up in your garden, you may have an issue with them blowing away. Some leaves will curl up as they dry, resulting in a lot of surface area. And that surface area, or shape, will easily catch the wind and be blown around. I have never had an issue with this, even though I have plenty of windy days. So, below I will detail three strategies to stop your leaf mulch from blowing away.
Compacting leaves by bagging or can
I am going to relay my situation here since I have 5 years experience and have never had my leaves blow away. My yard primarily has Black Locust trees, and these have tiny leaves that we don’t even bother raking. So, I have to get all my leaves from neighbors who are raking and throwing them away. They do this by raking and bagging them, or sucking them up with a lawnmower and then bagging. I come pick the leaves up that day or the next, and will then spread them on my garden.
In five years, I have never had my leaves blow to one side of my garden let alone blow away. So, if you are raking your own leaves, my advice would be to stuff/compact them in a spare trashcan, or place them in large trash bags and compact them by sitting on them or other means. Then, go dump them into your garden, and they should be quite interlocked.
Driving over leaves
Alternatively, if you have a riding lawn mower, you can drive over the leaves with blade shut off, you will compact the leaves in place. You can mow them, but I generally try to avoid this as it may kill pollinators that are over-wintering in the leaf litter.
Using water
Take a hose or sprinkler and thoroughly wet the leaf mulch. By getting them wet, the leaves will become more pliable, and thus easier to compact. Then, just walk over them or rake the wet leaves to ensure they are thoroughly interlocked.
Where to get leaves
In Autumn, as leaves are falling from trees you can find sources of them driving around. Depending on the area you live, people may put leaves out in trash or yard-waste bags right on the curb. This is actually how I get most of my leaves!
But even if they just pile them up along the curb unbagged, there is nothing stopping you from going out with your own bags and gathering them. One man’s waste is another man’s treasure, eh?
How to transport leaves
If you’re hauling leaves in bags, you don’t need a truck! You can do this in a regular Honda Civic like I do by placing them in the back seat. Now, sometimes the bags will be wet, or some water may leak out, and unsurprisingly I do not want any water on my seats. To avoid this I simply line the seats with old towels, and thus there is no problem.
Gardening in leaf mulch – planting seeds and plants
Alright, so come spring time how do we actually garden in a thick layer of leaf mulch? Well, for starters the leaves should be very compacted by May. They often shrink by 50% or more. But don’t just start planting seeds in the mulch itself – the leaf mulch acts as a weed barrier, and will stop your seeds from germinating too. But, I have found a method to plant seeds in Leaf Mulch which I will relay below.
How to plant seeds in leaf mulch
Ok, so a layer of leaf mulch prevents weeds from growing, acting as a barrier. So, to plant seeds in our garden with leaf mulch, we have to remove the leaves from where we wish to plant. But, that is not all we must do, as a common problem I’ve faced in the past is that the leaves may blow back over where I planted my seeds.
To overcome this, here is my process. Click on images to see full size.
- First, remove the leaf mulch from the row you wish to plant. I just dig my hands under the mulch and try to flip it over. We need to create exposed soil so plant our seeds.
- Next, plant you seeds. I like to do this by just pressing the seeds firmly into the soil. Then, I come through with a layer of compost on top.
- To keep the leaves from blowing back into the ‘trench’, I lay down boards. I use cedar pickets (not pressure treated). These are very cheap (~$5), and never rot.
That’s it, that is all you need to do to plant seeds directly into the soil. Sometimes the leaves are compacted and moist enough where you can just flip over the leaves out of the trench as a solid ‘mass’, and then you won’t need the boards. But this is the exception, not the rule. For rows, I would plan on needing the boards.
How to transplant seedlings in leaf mulch
Ok – so we have seeds figured out, but what about plants? Well, that is relatively simple. I’ve been doing this for five years without issue, so let me show my process below. Click on images to see full size.
- Pull the leaves away from the spot you want to plant. You can often pull the leaf mulch in chunks that stay together. Keep it like this, for use in the last step.
- Dig your hole and plant your seedling (add a handful of compost to the hole, if you have it).
- Put the leaves back, but leave a 2″ gap to the stem of the seedling. Remember how the leaf mulch came out in chunks? Well, we can put it back upside down, and it will hold together and not risk the stem getting buried.
The only real consideration to doing this is to make sure your small plants you are planting are taller than your leaf mulch. That way you know they can’t get buried by freak windstorms, etc.
Slugs and pests
One drawback with leaf mulch (any mulch) is that it will provide a haven for slugs. The deeper layers of leaves will usually be moist, and provide a perfect environment for slugs. Now, while many people have advised me to get chickens to come eat the slugs, I would rather just tend crops and not animals. So, what to do?
Well, the most effective and simple method for fighting the slugs that I’ve found is beer traps. Yes, beer traps. Go buy a six pack of cheap beer, and save some lids from jars or other small containers.
Place these containers around your garden, near plants that slugs particularly like to eat like cabbage, cauliflower, and broccoli. Press them into the leaf mulch so that the top edge of the container or lid is relatively even with the mulch. Then, pour a small amount of beer into the container.
It doesn’t take much beer to drown slugs. You do not need to fill up the container. The slugs will enter the container for the beer and drown. You will need to keep up with the traps, and keep them supplied with beer. Also, after rains you will need to dump/refill the traps. But, these are very effective at killing scores of slugs and allow your plants to get ahead of the slugs.
More gardening tips here
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