Autumn's Fallen Treasure

Every October and November, British gardens receive a delivery of free organic matter on a scale no garden centre could match. A mature oak drops well over 100,000 leaves in a single season, and a modest suburban lawn can collect several barrowloads before Bonfire Night. Handled badly, that bounty becomes a slippery hazard on paths, a smothering blanket on grass and a hideout for slugs. Handled well, it becomes leafmould: a crumbly, dark, sweet-smelling material that improves soil structure, feeds worms and fungi, and costs nothing but patience.

The trick is to think of leaves as a resource to be sorted rather than a mess to be cleared. Some go straight back onto borders, some go to the lawn mower, and the rest go into bags and cages to rot down.

Clearing Paths, Steps and Patios Safely

Wet leaves on stone, brick or timber decking are genuinely dangerous, particularly for older visitors and anyone carrying things. On sloping paths and steps, clear little and often rather than waiting for the whole canopy to fall. A stiff bristled broom or a rubber-bladed squeegee works faster than a fan rake on hard surfaces, and a leaf blower is fine for gravel and block paving provided you blow into a corner or onto a tarpaulin rather than into the street.

• Clear steps first, working from the top down, then sweep the landing.
• Keep gully drains, rainwater hoppers and soakaway grates free — a single mat of leaves can flood a driveway.
• Watch for moss and algae underneath; a scrub with a stiff brush after clearing is worth the effort.
• Bag leaves as you go rather than building unstable heaps that blow back across the garden.

Don't hose paving down afterwards unless you have to. A dry brush finish leaves less slick film than a wet one.

Lawns: Rake, Mow, and Let the Light In

A thin scattering of leaves on turf is harmless, even helpful, as worms pull them down and improve the soil. A thick, damp mat is another matter: it blocks light, traps moisture, encourages fusarium patch and red thread, and can kill patches of grass outright over winter. Fine-leaved varieties such as birch, ash and rowan break down quickly and can be mown in.

For light fall, raise the mower blades slightly and run over the lawn with the collector on, or use a rotary mower without a box and let the chopped fragments filter down between the grass plants. For heavy fall, rake first. A spring-tine rake is the traditional tool; a towed lawn sweeper or a plastic leaf rake with a fan-shaped head covers ground quicker on larger lawns. Collect the rakings and add them to your leafmould store rather than the green bin.

Avoid walking repeatedly over frosted or waterlogged turf. Compaction in November takes years to put right, and aeration in autumn is far easier on a dry, breezy day.

Borders, Hedges and Soil Life

Under shrubs and around the base of trees, leaves are an asset. Leave a layer 5–8cm deep around established woody plants, keeping it clear of stems and trunks by a hand's width to avoid collar rot. This mulch suppresses weeds, moderates soil temperature, and feeds the earthworms, springtails and mycorrhizal fungi that do the real work of soil building.

Take care with small herbaceous plants and alpines, which can be smothered. Lift leaves off them with a soft rake or gloved hands, then tuck the material around the surrounding shrubs. Hellebores, epimediums and woodland bulbs are adapted to leaf litter and generally cope well, but newly planted perennials are not.

• Never leave thick, wet heaps against tree trunks or hedge bases.
• Check piles before moving them — hedgehogs, frogs and toads hibernate in leaf litter.
• Wear stout gloves; damp leaf piles can harbour ticks and the occasional wasp.

Making Leafmould: Bags, Cages and Time

Leafmould is the simplest compost you will ever make. The recipe is leaves, moisture and time — no turning, no activator, no fuss.

• Bin bags: fill with damp leaves, punch a few drainage holes, tie loosely and stack in a corner. Best for small gardens.
• Wire cages: a cylinder of galvanised mesh about a metre across holds a surprising volume and allows air in. Ideal for larger properties and estate gardens.
• Wooden bays: two or three bays let you turn and grade material by age.

Thick, leathery leaves such as oak, sycamore, horse chestnut and beech take a year or two. Thinner leaves — lime, birch, cherry, hornbeam — rot in nine to twelve months. Shredding with a mower speeds everything up considerably, and mixing in a little grass clipping or a handful of soil introduces the microbes that get things going.

Keep the pile damp but never sodden, and covered from the worst of the winter rain. When the material has turned into a dark, crumbly, earthy-smelling mass with few recognisable leaves, it is ready.

Using Your Leafmould

Coarse, partly rotted leafmould makes an excellent autumn mulch for borders, roses, fruit trees and hedges. Finer, well-rotted material can be sieved and used as a seed-sowing mix ingredient, mixed with garden compost for potting, or brushed into the lawn as a top dressing in early spring.

In heritage gardens and estate landscapes, where mature trees shed in enormous volume, leafmould is often the single most valuable product the garden makes. It costs nothing, uses no peat, and returns to the soil exactly what the trees took out. Clear your paths, protect your lawns, and treat the rest as next year's compost — because that is precisely what it is.