Every fall in New England, our grassy backyard gets covered in fallen leaves. Maple, oak, and sycamore trees pull nutrients from their foliage in preparation for winter, causing the leaves to drop.
Most homeowners look at leaves as nothing more than a mess. But if you’re a gardener or landscaper, you should see them as a gold mine!
In this article, I’ll explain everything about leaf mulch. This simple by-product of deciduous trees can be used in several ways to help your gardens flourish! Let’s get started.
What is leaf mulch?
Leaf mulch is a layer of leaves that is applied to the surface of the soil around other plants. Like any mulch, it provides protection for the soil and plants.
The leaves can be shredded into small pieces, or left whole before being applied as a mulch. There are benefits and drawbacks to both options, which we will cover later on.
However, leaf mulch has more benefits than just tidying up your garden. Since it is natural and organic, it can improve the soil itself over time.
Learn how to make leaf mold (video):
What are the benefits of leaf mulch?
When you think of a natural forest, full of leaf-dropping trees, you may wonder how the plants can thrive and grow so strong. Part of the answer lies on the forest floor, where decades of fallen leaves sit and slowly decompose.
For one, the leaves protect the soil from heavy rain and erosion. They also suppress weeds and other plants (like grasses) from getting a foothold.
Besides that, the layers of leaves decompose and release vital nutrients back into the soil. With the help of worms, fungi, and other organisms, the leaves enrich the soil.
In the garden
Using leaves as a mulch for your vegetable garden is an excellent use case. Like in a forest, the leaves will reduce weeds, prevent soil erosion, insulate the soil from cold weather, and add nutrients over time. Raised beds or in-ground gardens both benefit from a thick layer of leaf mulch.
The best time to apply fresh leaf mulch to the garden is after transplanting in spring, just after the soil has warmed up. First, allow smaller plants to grow to 3-4″ tall, then apply a 2-3″ layer of leaf mulch to the surface of the soil.
For the lawn
If you don’t have a veggie garden, there is still plenty you can do with your leaves. According to Michigan State University, mulched leaves can be left on the surface of your grass lawn. In the fall, use a lawn mower to chop up the dry leaves into smaller pieces, leaving them evenly distributed across your lawn.
The shredded leaves will sift down around the blades of grass, and break down to release nutrients. There is even some evidence that the leaf pieces can stop weed seeds from sprouting the next spring!
For landscaped beds
While many homeowners choose to use wood or rocks as a landscaping material, leaf mulch can be a free alternative. For the best look, the leaves should be chopped into small bits first.
The benefits in your landscaped beds are the same as in the garden. Leaf mulch will help keep your plantings tidy, prevent weeds, and insulate tender perennials from intense cold and heat.
Best types of leaves for leaf mulch
Most tree leaves make great leaf mulch. If you have deciduous trees, such as maple, oak, or elm, then you can assume they are all great candidates.
Fresh green leaves should not be used, as they still contain higher levels of nitrogen. Wait for leaves to fall and begin drying out before processing them. This makes them easier to grind up, too.
Good trees for leaf mulch:
Do not use walnut leaves as a mulch, as they contain iodine. Iodine is toxic to some plants, and can cause slow or stunted growth, yellowing leaves, and even plant death.
Can you use pine needles as mulch?
While pine needles technically are leaves, they are not quite the same as leaf mulch. Normal deciduous tree leaves break down much faster than pine needles, and are more compact when used as a mulch.
With that said, pine needles make a perfectly suitable mulch. They are on the fluffy side, making them great insulators. They also break down slowly, meaning they don’t need to be applied as frequently.
We have used pine needles to insulate our garden beds through the winter, and it works great. However, we always keep our leaf mulch and fallen pine needles separate, given their different uses in the garden.
How to make leaf mulch
At this point, I hope you’re interested in using your leaves to make leaf mulch! Once we switched from straw and wood chips to leaves as our go-to mulch, we never looked back.
We prefer to shred our leaves into smaller pieces before using it as a mulch. This allows more water to penetrate the leaves and reach the soil, but does require some more up-front work.
If you don’t have a way to shred leaves, un-shredded leaves are still great to use as a mulch. However, they have a tendency to blow away in the wind, and are more bulky.
Steps to make leaf mulch (with a lawn mower):
- Pre-mow a patch of grass on the lawn. By pre-cutting an area of your lawn, you won’t end up with grass in your leaf mulch. The nitrogen in the grass can cause the leaves to be broken down more quickly like compost.
- Gather leaves into the pre-mowed grass. Rake leaves into an even layer on the pre-mowed grass.
- Mow over the fallen leaves. Using a side chute attachment, mow over the leaves to chop them up. Depending on the blade type (mulcher or regular blade), you may need to make a few passes to reach the right consistency.
- Use right away as a mulch. The shredded leaves can be gathered up with your lawn mower bag, or by raking, and used right away as a mulch.
- Store any remaining mulch in a pile. Any leftover mulch can be stored in a pile to slowly decompose into leaf mold for later use.
While the lawn mower works great (and it is our go-to method), you may not have one. But, if you have a weed whacker, you can use that to shred your leaves instead.
Steps to make leaf mulch (with a weed whacker):
- Gather leaves in a large trash can.
- Place weed whacker into the leaves and pulse to shred them. Be sure to wear eye protection when using this method!
- Use the shredded leaves as mulch. Once the leaves are shredded evenly, mulch around your plants or landscaping. Then, water lightly to keep the mulch in place.
- Store any excess leaves in a pile.
Again, shredded leaves are ideal in most cases, but full-sized leaves will break down, too. Just be sure not to suffocate out your plant roots with a layer that is too thick.
How to make leaf mold
While leaf mulch is great, leaf mold is even better. By allowing your leaves to sit and decompose for several months, they will release more nutrients to the soil as a mulch.
Steps to make leaf mold:
- Shred leaves using one of the methods above.
- Make a large bin to store the leaves. We used chicken fencing and T-post stakes to assemble a simple leaf mold bin. The holes in the fencing allow air to penetrate the pile, while also keeping the leaves from blowing away. Alternatively, stuff the shredded leaves into large black trash bags, and poke holes in it with a pitchfork.
- Water and turn the pile to evenly moisten. One of the key elements to making leaf mold is water. Just like you would with homemade compost, add water and turn the pile. Do this until the pile is evenly moist, but not soaking wet.
- Allow to sit for 6-12 months, turning occasionally. Over the course of a year or so, the leaves will slowly decompose with the help of fungi. Use a pitchfork to mix up the pile every few weeks, and add water if necessary.
- Use as a mulch or soil amendment. When it’s done, leaf mold will resemble a crumbly, dark soil. You may also see white filaments within the leaves. This is normal, healthy fungal growth.
Leaf mold is broken down, and will help feed the soil more readily, just like compost. Use it as a side dressing for the veggie garden, raised beds, trees, landscape plants, or anything that needs a boost of nutrients.
How to use leaf mulch
Leaf mulch should be applied in a thick layer around garden plants, trees, or shrubs. Some plants will benefit more from spring mulching, while others aren’t as picky.
Where to use leaf mulch/mold:
- Annual garden plants (in spring)
- Perennial garden plants (any time)
- Trees, at time of planting, then annually
- Lawns (shredded only)
Whether you have freshly shredded leaves, or decomposed leaf mold, a layer of leaves will benefit your plants and soil in the long run.
Does leaf mulch attract insects?
One main concern homeowners have about mulch is attracting pests. Termites, ants, and earwigs can all be attracted to mulch for the moist conditions it creates.
Termites typically do not eat leaves, and are more likely to feed on wood mulch, such as pine or cypress. However, the leaf mulch can attract termites if there is not a more suitable place nearby, potentially leading them to your house.
It is always best to keep any mulch at least 1-2 feet from your house. This will help reduce the chances of pests entering your home and potentially causing damage.
It is normal to find earthworms, millipedes, and pill bugs underneath your leaf mulch. These small animals, along with fungi, help break down the leaves over time. So if you see them in your mulch, consider it normal and healthy.
Making leaf mulch is a great way to reduce waste and recycle a natural resource. While we use ours mostly in the garden, it has a wide variety of other uses. By using our fallen leaves, we have saved money while improving our gardens at the same time!