Casual Gardener: Harness nature's annual windfall
Look on fallen leaves not as an untidy nuisance but as a valuable resource, writes John Manley
FEW things represent nature’s circle of life better than the relationship between deciduous trees and their leaves. Over the past growing season the leaves have been converting the sun’s energy into the sugars and starch that fuel the tree’s growth but now they are spent, shed from the dying canopy and left to carpet the areas around the base.
In a natural setting, many of the leaves would rot down where they fell, their organic goodness eventually absorbed back into the tree through its roots. The dark, rich hummus that the decomposed foliage slowly turns into is the envy of many gardeners.
But the clever ones know how to harness this annual windfall, turning it from a nuisance that is the ideal hiding place for dog turds into leafmould, an asset that can be used as a soil conditioner and mulch or as a key component in homemade potting compost.
The first things to understand about making leafmould is that it’s quite a long process and that not all leaves are suitable. Fallen leaves from common deciduous trees, such as oak, birch, sycamore and beech are ideal, whereas evergreen leaves like laurel and holly aren’t.
Conifers are also unsuitable, but pine needles can be used to make a separate ericaceous compost for acid-loving plants.
Start by gathering your leaves with a fanned rake or a leaf blower, or even appear the dutiful citizen by sweeping them up off the street.
The most straightforward method for transforming your leaves into a desirable, crumbly compost is the bin liner method. Quick and tidy, this simply involves filling large black bags with leaves, adding a bit of water and puncturing the bag with a fork before leaving them in a quiet corner of the garden for up to two years. When you return, the leaves should be well rotted and no longer be recognisable.
If you have plenty of room, you can employ the traditional pen method, which involves making a chicken wire cage and filling it with leaves, always ensuring you add some water to get the process going. Again, somewhere out of the way in the garden is perfect for accommodating this this drawn-out process.
Any large container, as long as it is ventilated, will do the job, including a conventional compost bin.
There are a number ways to speed up the process, including with commercially available accelerants, many of which claim to half the time you have to wait before harvesting your ‘black gold’.
A more tried and tested method is to shred the leaves before storing them according to your preferred method. Some blowers have incorporated shredders but arguably the most efficient and least labour-intensive way is gather the leaves together and run your mower over them.
Some may advise adding grass cuttings as a way of saving decomposition time but tests carried out a decade ago by Which? Gardening found there was little basis for this claim.
Although great for conditioning the soil, leafmould, like peat, has little nutritional value. If you want it to fertilise, add nutrient rich substances like dried blood or seaweed.
When the rotting process is complete, you can use the leafmould as you would any other compost, either by digging it in or as a mulch. The very well-rotted stuff can be used for seed-sowing and potting compost, though often additional materials like grit and vermiculite are required to obtain the correct consistency and texture.