How do I make leaf mould?
Turning autumn leaves into the best free soil conditioner there is, with almost no effort.
- Difficulty
- beginner
- Time
- 1 hr
- Read
- 2 min
Short answer
Collect fallen leaves, put them in a bin bag with a few holes punched in it, dampen them, tie it loosely and leave it somewhere out of the way for a year. That is the entire process. Leaf mould is made by fungi rather than bacteria, which is why it needs time rather than turning.
Leaf mould is the easiest soil improver to make and costs nothing. Unlike compost, which is a bacterial process needing heat, air and a green-brown balance, leaf mould is fungal — it needs only leaves, moisture and patience.
What you'll need
- Fallen leaves
- Bin bags or a wire cage
- Water
- Garden fork (optional)
Step by step
- Collect fallen leaves in autumn, ideally when damp.A lawnmower run over leaves on the lawn collects and shreds them in one pass, which speeds decomposition considerably.
- Put them in bin bags or a simple wire cage.Bags are easier for small quantities; a cage of chicken wire and stakes suits larger volumes.
- Punch a few holes in each bag for air.Fungi need some oxygen. Completely sealed bags go anaerobic and slimy.
- Dampen the leaves if they are dry.They need to be moist throughout. Dry leaves simply sit there for years.
- Tie the bags loosely and put them somewhere out of the way.Behind a shed, under a hedge. They need no attention at all.
- Leave for a year for a rough mulch, two for fine leaf mould.One year gives a coarse material good for mulching. Two gives a fine crumbly product good for seed compost.
- Keep oak, beech and hornbeam separate if you can — they make the best leaf mould.Thick evergreen leaves and conifer needles break down very slowly and are better shredded or left out.
- Use it as a mulch, a soil conditioner, or mixed into potting compost.It adds almost no nutrients but it improves structure and water retention substantially.
Tips
- Shredding leaves with a mower before bagging roughly halves the time it takes.
- Leaf mould is a soil conditioner rather than a fertiliser — it improves structure and moisture retention but adds few nutrients.
- Clear leaves off lawns and paths but leave them on beds where they can rot down naturally and shelter wildlife.
Common mistakes
- Sealing the bags completely — Fungal decomposition needs some air. Sealed bags go anaerobic and slimy rather than crumbly.
- Bagging dry leaves — They need moisture to break down. Dry leaves in a bag are still dry leaves two years later.
- Adding leaves to a compost heap in bulk — They break down by a different, slower process and can mat into airless layers.
Questions people ask
How long does leaf mould take?
About a year for a coarse mulch and two years for fine, crumbly leaf mould. Shredding the leaves first with a mower roughly halves that.
Can I put leaves in my compost bin?
Small quantities mixed well, yes — they count as a brown. In bulk they mat into airless layers and break down too slowly. Bag them separately for leaf mould instead.