Ok I love leaf mulch. Nature gives us an abundance of leaves in the autumn. Natural systems (forests) use this abundance to create soil. I love mimicking natural systems to benefit my garden and growing system.
So join me in this question and answer guide to making leaf mulch quickly here in the UK.
What is leaf mould?
When autumn leaves break down, the product is leaf mould. It is a soil conditioner and soil enhancer. Leaf mould provides a mulch which prevents water loss and protects the soil from erosion. It improves the soil by building in more air pockets, enhancing the soil’s aeration. These micro pockets for air also allow water and nutrients to travel through the soil making them more available to your plants.
What is the difference between leaf mould and leaf mulch?
The honest truth is that both words are often used interchangeably to mean the same thing. However there is a technical difference between them.
Leaf mulch is taking autumn leaves and using them directly as mulch in your garden. Placing the fallen leaves on beds to act as mulch. It could also be a case of storing them for around 6 months so that they are semi broken down and using them as mulch.
Leaf mould on the other hand is taking autumn leaves, leaving them in a pile or heap to break down for a longer period of time (typically 2 years). The product created from this process is leaf mould. It is like compost in consistency, but with fewer nutrients.
Leaf mould can be added to your garden as a mulch or soil improver, in the same way as leaf mulch. If the leaves are left to break down for a couple of years they will turn into a product that can be used for seed sowing or potting compost.
How do you make leaf mulch fast?
To speed up leaf mulch decomposition you need to provide optimum conditions to allow the breakdown to occur. Here are a few top tips:
Tip 1: Use a starter.
Using old leaf mulch that is full of bacteria, microbes and other soil life as a starter will help to speed up the process. I think of this like a sourdough starter, anything that requires bacteria or microbes to make a process happen can be sped up by introducing the existing bacteria to the food source (the leaves) rather than waiting for the bacteria to slowly multiply.
Tip 2: Add nitrogen
Human urine is a great source of nitrogen which can really get the breakdown process happening. Not too much otherwise it will get too wet.
Another source of nitrogen is glass clippings. Again not too much otherwise there will not be the air spaces to achieve the breakdown.
Tip 3: Small pieces
Use a mower to shred the leaves into smaller pieces. This will increase the surface area available for the microbes to work on speeding up the time for decomposition.
Tip 4: Protection
Leaf mulch is often stored in a wire mesh container. This is very airy which cools down and breaks up the process. The leaf mulch can also get very wet and soggy stored in wire – not optimal.
You will achieve quicker results storing your leaves in a plastic bag or an enclosed compost bin. This protects the leaves and the process so that optimal conditions can be maintained inside the bag. Always remember to pierce holes in the bag for drainage.
Tip 5: Turning
Turning the pile of leaves will speed up the process because it will introduce more air boosting the microbial activity.
Can you make mulch from leaves?
Yes. Nature is always the best guide, and in nature there is no waste. We ‘throw things away’, in nature there is no ‘away’ to throw things. Leaves are a great example of this. Trees drop their leaves in the autumn and these leaves are a valuable resource. The soil life soon sets to work breaking down the leaves, extracting the goodness and turning the leaves into a mulch, a soil conditioner or a soil enhancer.
So if nature does it without any help, then this is something we can do in our home gardens.
One of the big differences to a natural forest is that urban and semi-urban environments contain a lot of hard surfaces, concrete, tarmac and paving. So when leaves fall they do not always land on the earth for worms and other soil life to take action. This is where we can help.
Gathering autumn leaves and storing them allows all of the worms, bacteria, microbes and soil life to set to work on breaking the leaves down into a wonderful mulch that can be used on the garden.
How long does it take to make leaf mulch?
Typically it can take up to 2 years. But it depends on lots of factors, such as how and where the leaves are stored, type of leaf and what you want to use the mulch for. In many cases a partially broken down mulch is adequate, with the final breakdown happening in situ.
For a fine leaf mould that can be used for potting compost, this is likely to take up to 2 years.
Can you mulch too many leaves?
No. Just ensure that you have enough space to store and protect the leaves whilst they are mulching. If you are mulching in situ on a bed too many leaves may become unwieldy and leaves may start to get blown around, or spread to the lawn. Leaving a pile of mulching leaves on a lawn will damage the lawn, because the leaves will block light and prevent the grass from growing.
Is leaf mold better than compost?
Leaf mould and compost are two different things. Lead mould has much lower nitrogen levels than compost. It is great to use as a potting mix.
Leaf mould can also be used as a mulch if you do not want to increase the nitrogen levels in the soil. It is a mulch that protects and enhances the soil structure without adjusting the fertility.
Compost is great if the soil fertility needs to be improved. It can also mulch and is good for soil structure.
Often the two can be used mixed together to create the perfect balance that is suitable for many plants.
Are rotting leaves good for the garden?
Yes, rotting leaves are good for the garden. The rotting leaves improve soil structure, which helps with aeration and the ability for water and nutrients to be made available to the growing plants. Rotting leaves can counteract the effects of compaction by improving soil structure.
Are rotting leaves good for compost?
Yes, in moderation. Autumn leaves would be considered ‘browns’ in the compost mix. Fresh green leaves would be ‘greens’. So as long as you keep a balance within your compost bin then rotting autumn leaves can provide an excellent source of browns.
How long do leaves take to compost?
If mixed into the compost bin as part of the browns in your mix then they will take 3 – 4 months typically (depending on the time of year – slower through the winter). If leaves are being broken down on their own into leaf mulch then it will take longer (up to 2 years) than breaking them down into compost.
Can you plant directly in leaf mould?
Yes you can. A fully broken down leaf mould is great for a seed sowing compost. Mix the leaf mould with sharp sand and garden compost to make a potting mix.
Plant directly into the soil through the leaf mould for leaf mould or leaf mulch applied to the soil surfacae. It would depend on the thickness of the leaf mould as to how much soil vs leaf mould the plant was being planted into. The roots of the plant can grow down into the soil for nutrition. The leaf mould helps to improve the soil structure and protects the soil surface from erosion and evaporation.
Don’t forget to look at nature. Many seeds germinate on the forest floor in the leaf litter. We can emulate this in our gardens. As long as there is sufficient light, water and protection for the young plant and access to nutrition as it grows.
How do I make leaf mould to nourish my garden?
At it’s very simplest, gather a pile of autumn leaves. Let them sit in a pile for a year or two. Spread them on the garden and let the worms do the work of bringing the decomposed leaves in the soil.
What leaves should not be composted?
- Evergreen leaves will take a very very long time to break down. I tend to leave pine needles, holly and other evergreens in a woodland wildlife pile. I know that eventually they will decompose but not in the time that I want to make compost. The other thing people do is to put these out for council collections. Evergreens will compost at the higher temperatures of industrial composting systems.
- Roadside leaves – leaves gathered from alongside a busy road could be covered in petrol or oil from the roads. I also find pieces of litter in these types of leaves. When composting roadside leaves just pay attention to where you collect them from.
How do you compost large amounts of leaves?
For large amounts of leaves there are two main strategies:
The first is to leave them in a big pile for a longer amount of time. It will take longer to create compost from a larger pile. Turning the leaves will speed this process up.
The second strategy is to mix the leaves with compost materials. So mix the brown leaves with equal amounts of green materials (fresh leaves, grass clippings, kitchen scraps) to make compost rather than leaf mulch.
Or you could do half and half and make some compost and some leaf mulch.
How to make a leaf mould bin
We use our compost bin design for leaf mould too. There are simpler versions – you could just use a bag, or even just a pile of leaves. We use our bin to keep things neat and tidy. We also have an old dalek style compost bin that we use for storing leaves. Many people like to use chicken wire. There are so many different ways to do it, it all depends on your time and budget. Always keep in mind that the simplest solution that is totally effective is just a pile!
Conclusion
Nature’s bounty of autumn leaves is a freely available resource that all gardeners should make use of. Otherwise the council simply takes them away. Keep it local, harvest this free resource and make your own soil enhancer this autumn.
Let me know in the comments below how you got on!