WITH the dry summer the UK has had, some trees are already shedding their leaves. To me, that means one thing: leaf mould. This unappealingly named substance, made by collecting autumn leaves and letting them rot for a year or two, can be used as a growing medium and soil improver and is easier to make than garden compost.
Compost heaps are a great way to get rid of garden and kitchen waste, but they take work to build up and feed with the right mix of materials, and turning them over can be heavy going. Dry autumn leaves, though, can be collected in just a couple of hours.
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As leaves turn brown in autumn, the tree is reabsorbing many of their nutrients. By the time they fall, they have a much higher carbon content relative to nitrogen than fresh leaves do. This means that autumn leaves can鈥檛 be broken down by the bacteria that feast on green garden waste, and are instead broken down by fungi.
Dry autumn leaves therefore take longer to rot than fresh leaves, which is why it isn鈥檛 a good idea to add them to compost bins in large quantities. But, once collected, you can more or less leave them to it.
If you have the space, you can build a small cage for storing the leaves, using chicken wire for the walls and a post at each corner. An easier option is to store them in black plastic bin bags.
Leaves from most deciduous trees are fine, but bigger and thicker ones, such as those from horse chestnuts, take longer to decompose. One solution is to shred them before bagging. If the leaves are lying on your lawn, run your lawnmower over them and tip the grass box straight into the bin bags. It doesn鈥檛 matter if some grass clippings are mixed in.
I have previously 鈥渉arvested鈥� leaves from the street, where they were conveniently swept into piles. But don鈥檛 take them from busy roads in case they harbour pollutants. Nor should you take leaves from forests 鈥� the woodland soil needs them more than you.
Fill the bags about three-quarters full and dampen the leaves with water if they are dry. Tie the top, then stab with a garden fork so air can get in. You can help the decomposition by shaking the bags a couple of times per year.
It takes a good two years for the contents to rot down into leaf mould, which is a dark-brown, crumbly and light-textured substance. Once sieved, it is good for sowing seeds in, unlike home-made garden compost, which would be too dense. For potting on young plants, mix one part leaf mould with one part garden compost and one part horticultural sand.
If you can鈥檛 wait so long, after one year you can use the partly rotted leaves as a general soil improver or an organic mulch, a substance used to cover the soil around the base of plants to reduce moisture loss and keep down weeds.
What you need
Black plastic bin bags
A garden fork
Storage space
Autumn leaves
Clare Wilson is a reporter at 快猫短视频 and writes about everything life-science related. Her favourite place is her allotment @ClareWilsonMed
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