Carol Klein on the magic of leaf mould
Give your garden a thick mulch now for great results next year
Much of the winter work here in the garden at Glebe Cottage is invisible; a great deal of it is more about taking away than adding to. We’re collecting leaves, trying to pick up as many as possible, stack them and eventually turn them into leaf mould. We’re cutting back stems and faded leaves to swell the compost heap and open up the garden so that paths and ways through become obvious.
The bones of the garden are revealed a bit at a time, its order is re-established and though it may feel sad to say goodbye to the remnants of summer past, cutting back and tidying creates the conditions for the year ahead. For the foreseeable future it’s all about the black stuff, or at any rate the dark brown stuff!
Those are the colours of the best ingredients in the recipe for a better garden next year. First of all compost, which by now is fine and dark and showing little sign of the garden debris used to make it. Well-made compost is a boon, improving the structure of your soil, whether it be light and sandy or claggy clay. It increases the number of micro-organisms, too. Soil is alive, and feeding it is the best way to feed your plants.
Then there’s leaf mould, dark and crumbly too, but made through a totally different process than that which creates compost. Compost is made with oxygen, that’s why you turn your compost heap, putting more air into it and enabling micro-organisms to break down the material within it faster.
The leaves in leaf mould break down mainly due to fungal action. It’s a slower process; anaerobic, meaning it doesn’t need oxygen and its action needs no light. If you’ve no other way of making a leaf mould heap then black plastic bags can be used. We recycle compost bags, turning them inside out so they aren't such an eyesore.
People ask why we don’t just leave the leaves on the beds where they fall, surely it would be so much easier and mean much less work. If we had acres of woodland then we might do that but because we’re gardening in a relatively small area with several trees and the beds around them are intensively planted with all manner of treasures, we need to leapfrog the process. If we left enormous wodges of leaves, several inches deep, covering these treasures, many of them might not survive.
We plant much more intensively than Mother Nature would so we need to adopt practices that take account of this, even when this means we’re replacing leaves with leaf mould, we’re removing competition by weeding thoroughly and we’re dividing and feeding our plants from time to time, which would never happen in nature.
Mulching is a vital part of successful gardening. It suppresses weeds, helps retain moisture and a thick covering of leaf mould or compost also helps insulate the soil, so there’s less likelihood of soil freezing in the winter or frazzling in the summer. Mulch also protects the surface of the soil from erosion by both wind and rain.
'Mulching is a vital part of successful gardening. It suppresses weeds, helps retain moisture and insulates the soil'