Leaf mould is one of the best soil conditioners you can use, and it is completely free. All you need is autumn leaves and a bit of patience.
What is leaf mould?
Leaf mould is decomposed leaves. Unlike compost, which is broken down by bacteria, leaves are decomposed mainly by fungi. This takes longer but produces a crumbly, sweet-smelling material that is excellent for improving soil structure.
Why make leaf mould?
- Improves soil structure in both clay and sandy soils.
- Retains moisture while improving drainage.
- Makes excellent mulch.
- Two-year-old leaf mould can be used in seed and potting composts.
- It is free!
How to make it
- Collect leaves: Gather fallen leaves in autumn. Most deciduous leaves work well – oak and beech are particularly good.
- Shred if possible: Running a mower over leaves speeds up decomposition, but it is not essential.
- Contain them: Put leaves in a wire mesh bin, black bin bags with holes punched in them, or a simple enclosure made from posts and chicken wire.
- Keep moist: Leaves need moisture to decompose. Water them if they dry out.
- Wait: Leaf mould takes 1-2 years to form. One-year-old leaf mould is good for mulching. Two-year-old leaf mould is fine and crumbly, suitable for seed composts.
The bin bag method
If you do not have space for a leaf bin:
- Fill black bin bags with damp leaves.
- Punch a few holes in the bags for air circulation.
- Tie loosely and stack in an out-of-the-way corner.
- Check occasionally and add water if the leaves have dried out.
Which leaves to use
- Best: Oak, beech, hornbeam – break down to a fine texture.
- Good: Most deciduous leaves including sycamore, lime, apple.
- Slow: Thick, leathery leaves like horse chestnut and walnut take longer.
- Avoid: Evergreen leaves like laurel and holly do not break down well. Conifer needles are very slow and acidic.
Using leaf mould
- Mulch: Spread around plants to retain moisture and suppress weeds.
- Soil improver: Dig into beds to improve structure.
- Potting compost: Mix well-rotted leaf mould with loam and sharp sand for seed sowing.
- Lawn top-dressing: Sieve and spread thinly on lawns.
Do not waste autumn leaves by sending them to landfill. They are a valuable resource that costs nothing to turn into something your garden will love.
Written by Dave Thompson
Professional Gardener & Founder
Dave has over 15 years of experience in garden maintenance across Staffordshire. He founded Hedge Cutting Staffordshire in 2009 and has helped hundreds of homeowners create and maintain beautiful gardens. When he's not out trimming hedges or advising clients, he's testing the latest garden tools and sharing practical tips on this blog.
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