Transform autumn leaves into valuable leaf mould, which is as easy to use as mulch, soil conditioner or a seed compost. Learn more in our guide below.
What is Leaf Mould?
Leaf mould is made from the decomposition of leaves. These decomposed leaves break down into a thick, black crumbly substance known as leaf mould. People often confuse leaf mould with leaf mulch. While both are made from leaves, leaf mulch is a layer of freshly shredded leaves that is placed on top of the soil.
Leaf mould is made up of shredded leaves that have been left to decay further over a long period, typically one to two years. the process gently breaks the leaves down into a refined compost. Where leaves are the sole material.
How Does Leaf Mould Work?
While leaf mould doesn’t add many nutrients to your soil, it is a great natural conditioner. Leaf mould aids soil structure and helps it retain moisture. For the best results, you should add a layer of leaf mould to the soil, turn it into the top soil, and then add compost to provide the soil with additional moisture and nutrients.
How To Make Leaf Mould
1.Prepare the storage area to make leaf mould: Owners of small gardens may prefer to make leaf mould in black bin liners with holes in, storing them in a suitable location. The back of a shed or garage works great. For larger gardens, you can either pile your leaves in a hidden, shaded corner of your garden, or a leaf bin. To make a leaf mould bin, simply place four, three-foot posts into the ground creating a square or rectangle. Staple chicken wire around the posts removing any sharp edges or points. It is important that you can reach into the bin to enable you to turn the leaves each month and remove the leaf mould when required.
2.Collect leaves: There are a couple of simple ways to collect leaves. You can use an ordinary garden rake to collect leaves into a pile and pick them up, but the quickest and easiest way is to use a leaf blower or vacuum. Which typically have collection bags attached that neatly collect the material for you. When collecting leaves on a windy day, remember to blow the leaves in the same direction that the wind is blowing. Otherwise, you will spend hours re-collecting leaves you have already collected. Not all leaves are suitable to make leaf mould. Before making leaf mould, you need to make sure that any leaves you collect are disease free. If you use disease ridden leaves when making leaf mould, you risk infecting any vegetation when you add the leaf mould to the soil. You also need to ensure that you do not use leaves containing rubbish. The rubbish will not break down and may contain contaminants that will damage your garden.
3.Shred your leaves: Shredding your leaves before adding them to your leaf bin will speed up the decomposition process, enabling you to use your leaf mould more quickly. To shred your leaves, you can use a garden shredder or mow over them a couple of times with a rotary lawn mower. While it is not necessarily essential that you shred your leaves, un-shredded leaves tend to become compacted in the leaf bin, preventing oxygen and moisture from circulating and preventing decomposition.
4.Add your shredded leaves to the leaf bin: The last step in making leaf mulch is to add them to your leaf bin. If you are using bin liners to create leaf mulch when the bag is nearly full, lightly sprinkle with water and tie the bag together, then store in a shaded area of the garden. If using a larger leaf bin, loosely pack the leaves into the leaf bin allowing the air to circulate between the leaves and moisten slightly.
5.Leave them: Leave your leaves to slowly break down over the next 6-12 months, gently turning every month to allow the air to circulate. If you are using the bag method, then shaking the bag is just as good. Ensure that the leaves are moist, but not wet - and by next autumn the leaves should have turned into lovely leaf mould and be ready to add to your garden.
How To Use Leaf Mould
Adding to garden beds throughout your garden will improve soil structure and water retention. It’s perfect for gardens where you can see that excessive drainage is taking place, for example; raised flower beds can really benefit from additional leaf mould. Reinforcing your soil with leaf mould will ensure that valuable nutrients and moisture are more likely to be retained so that your garden remains healthy.
If you have the time, once your leaf mould is ready it can be sieved and separated into piles dependent on its coarseness.
1.When potting plants, consider mixing finer mould with compost. A 50:50 mix will not only bulk out your compost. It will give the compost a better texture, and the blend will give impressive growth results, rivalling store-bought compost.
2.The thickest mould, typically an inch or so in size is made up of the bits that haven’t quite crumbled yet. Mostly comprised of larger leaves, this mould makes for a great mulch. It’s heavy and thick and has no trouble suppressing pesky weeds by cutting out the light they’re fighting for.
3.The smaller, more refined mould, free of small twigs and roughly half an inch in size is the best soil amendment. It’s rough enough to bind together loose or sandy soils, massively improving its water retention. While not packed with nutrients, but shoring up soil will promote the good qualities it already has and allow it to improve as time goes on.
4.Leaf mould is a great way to keep your compost pile thriving too; a little sprinkle turned through every time you turn your compost will give snails, slugs and earthworms more reasons to stay and work their magic.
Is it acidic or alkaline?
When leaves have freshly fallen, they’re slightly acidic, typically below 6pH. As they break down, they move closer to pH neutral. Leaf mould is not a corrective measure for pH problems, but it will temper those issues in the short-term.
How does it differ from compost?
They are somewhat similar, but the process of creating leaf mould uses only leaves, rather than a variety of both green and brown organic material to make compost.
Leaf mould on its own won’t provide any nutrition compared to nutrient-packed compost. The lack of microbes and aeration means that leaf mould can take anywhere from 6 to 12 months to decompose.
What are its benefits?
By adding it to your soil and compost when preparing your beds for vegetation, your soil’s texture and fertility will significantly improve.
Its coarse texture makes soils better at retaining water, therefore reducing potential nutrient loss sustained by rainfall and excessive drainage.
Is it good for my garden?
You’re promoting biodiversity, collections of decomposing leaf mould not only give plenty of opportunity to decomposers to thrive, but you might plenty of variety too. Toads may make their temporary homes here, even voles burrow their way in, and you’ll soon find birds zipping around your stock, feeding on the bugs it attracts. Always be careful when reclaiming your leaf mould, as not to disturb these visitors too much. It’s a patient process after all.