The leaves go through three stages to become leaf mould. Firstly, springtails get to work on them, nibbling and excreting tiny parts of the leaves. After this, hordes of invertebrates such as millipedes, worms and fly larvae eat and process most of the tissue. Microscopic fungi then finish the job by tackling the tougher, stalky parts of the leaves.
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This way, millions of tiny creatures, micro-organisms and fungi turn leaves into rich soil-like material that provides three-quarters of the nutrients a tree needs every year. Leaf litter helps build up soil levels and improves its structure and biodiversity. In our gardens, we'd be mad to throw this away. You can buy compost instead of making it, but leaf mould has to be homemade.
I never have enough leaf mould, probably using most of it for potting mixes, adding it to homemade compost. This living brew supplies food for plants for a long time. You can also mulch with leaf mould, either using it as top dressing for containers or spreading on a border. It conserves moisture and, when 10cm thick, prevents weeds from germinating.
Leaves should be cleared up in some parts of the garden, including the lawn, which stops them smothering and killing the grass. But it couldn't be easier to run a rotary mower over the lawn once a week. The blades chop up the leaves and collect in the grass box, all ready for putting in a leaf mould bay (see panel) or a black plastic bag.
Leaves in a pond are more problematic. The bacteria that start breaking down fallen leaves in water use oxygen and at this time of year oxygenating plants are no longer working, so the oxygen levels in the water can become badly depleted, thereby damaging the pond's ecosystem. Prevent this by covering the water with net, which you remove and empty. Alternatively, scoop out the offending leaves with a net.
Gravel paths are more challenging, but a leaf blower is the best answer, especially if the path is next to the lawn. Blow the leaves on to the lawn and sweep up with the mower.
There are four ways of dealing with the leaves you've collected. Some, such as ash and apple, only take a few weeks to rot, so they can be added to a compost bin. They'll be composted more quickly than other garden rubbish. Leaves from oak and beech take an extra year to break down. Tannins in the leaves weather slowly, preventing soil fauna then fungi from getting to work. Evergreens, such as rhodies, conifers and holly, have thick, waxy coatings and take even longer. These leaves shouldn't be composted in the normal way but should be stored separately for several years.
You could have a special wire leaf mould bay for evergreens and a different one for deciduous ones. Winter rains keep the leaves good and moist. Before long, the heap will seethe with worms, micro-organisms and fungi, and you'll end up with leaf mould in 18 months (30 months for beech and oak).
An alternative that frankly doesn't work for a lot of people is to soak your leaves, put them in bin bags and make drainage holes with a fork. Keeping moisture levels right and attracting composting fauna and fungi into the bag can be difficult. The leaves often look much the same after a couple of years.
If you don't have space for a leaf mould bay, get the best from your leaves by composting or finding ways to use fresh leaves around the garden. If they've fallen on a border, leave them be. They'll act as a mulch, slowly rotting and improving the soil. You can also use fallen leaves to provide winter protection for the crowns of semi-tender plants or freshly planted lilies.