We often talk about the importance of keeping the root circle of your trees covered with woodchip mulch. You can make your mulch even better by introducing a mix of decomposed leaf litter into it. This will more closely resemble the forest floor conditions in which your fruit trees’ ancestors evolved. Leafy material will enable a wider diversity of microrganisms to coexist, bringing the soil into a healthy balance. This will both feed your trees and protect them from disease. It will also dramatically increase the aeration and drainage of the soil. Not to mention increasing the food available for worms, invertebrates and, ultimately, animals and birds.
HOW TO MAKE LEAF MOULD
- Gather leaves as soon as they start falling, while their nitrogen content is high and their cells are still hydrated (and therefore more amenable to decomposition)
- If you have access to a lawn mower, shredding the leaves with it will accelerate their decomposition
- Gather leaves (only) into a cage (see below) covered with tarp, or bin with air holes. Turn occasionally, keep aerated and moist.
- If you don’t have a cage or bin, gathering into bin liners or rubble sacks with a few holes poked in will also work, but will not have the advantage of contact with the soil and its team of decomposing organisms.
- Shredded, well-turned leaves can be ready in 6-12 months. Otherwise it may take 2-3 years to see the crumbly texture of humus that you are looking for. So start now and plan for the years ahead.
- When ready mix your leaf mould with your woodchip mulch and create a wide (at least 1m) circle around your trees, leaving a ‘doughnut’ hole around the base of the trunk (to protect the graft-union from rot). The proportion should be about 3:1 woodchip to leaf mould.
BUILDING A LEAF MOULD CAGE
You can easily make a square cage with chicken wire stapled to small wooden stakes at each corner or tied to bamboo canes with garden wire. Keep it simple and lightweight so it’s easy to move if needed. Cutting a door on one side will help with removing and turning the pile, but be careful of exposing sharp edges of the wire mesh.
A NOTE ON USING STREET LEAF LITTER
Current Environmental Agency legislation bans the use of street swept leaf litter in composting – so the majority ends up in landfill or is incinerated. The EA is currently investigating new methods of mitigating the contamination risk and may review their ban soon. So, while research indicates that such contaminants are unlikely to affect top fruit, it is probably best to avoid using leaf litter collected along busy roads for mulching. There are plenty of leaves available from public parks and green spaces.