Leaf Mould
Amendment
Leaf mould is the soft, dark material made when fallen leaves break down slowly. It is one of the gentlest and most useful soil conditioners for a UK garden, improving moisture retention and structure without being overly rich. Collect autumn leaves to make it, then use the finished material as mulch or in peat-free mixes.
What it is
Leaf mould is produced mainly by fungi decomposing leaves over one or two years. Mature material is dark brown, friable and woodland-scented, with few recognisable leaves remaining. It is usually lower in nutrients than garden compost or well-rotted manure, but excellent at improving soil texture, water retention and biological activity. It suits sandy, silty and clay soils alike, and is particularly useful around woodland-style plants. Thick, leathery leaves break down more slowly than softer leaves. Leaf mould is not usually a complete seed compost, although it can be blended with other suitable peat-free media.
What to do
Gather fallen leaves in autumn, avoiding diseased leaves where possible. Put them in a ventilated bin, a wire cage or perforated sacks, moisten them if dry and leave them to decompose. Shredding leaves with a mower speeds the process, but is not essential. After a year, use partly decomposed material as mulch; after longer, use the finer material to improve beds or blend into peat-free container mixes. Spread it over soil rather than burying large quantities deeply. Keep a separate store from the main garden compost heap, as leaf mould needs a slower, fungal process.
Tips
Do not send valuable leaves away if you have room to store them. Mix dry leaves into the compost heap when green materials are plentiful, but reserve some for leaf mould. Use a light layer around plants after weeding. Keep leaf mould moist enough to decay, yet open enough for air to circulate.
Leaf Mould: frequently asked questions
What is leaf mould?
Leaf mould is produced mainly by fungi decomposing leaves over one or two years.
How do I improve leaf mould?
Gather fallen leaves in autumn, avoiding diseased leaves where possible.
What are some tips for leaf mould?
Do not send valuable leaves away if you have room to store them.
General guidance for UK gardens and allotments. Page updated 18 Sep 2026.