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Making leaf mould


by Kate Bradbury

Every autumn I fetch leaves from the park to make leaf piles for frogs, beetles, and other garden wildlife. But this year I collected a few extra bags, to make leaf mould.


Every autumn I fetch leaves from the park to make leaf piles for frogs, beetles, and other garden wildlife. But this year I collected a few extra bags, to make leaf mould.

Relatively low in nutrients, leaf mould doesn’t feed the soil, but 'boosts' it, increasing soil-borne organisms and generating humus. There’s no need to dig it in - applied as a mulch, it's taken deep into the soil by worms. The only snag is it takes two years to make.

There are various ways to make leaf mould. Unlike compost, which rots with the help of bacteria, leaves are mainly broken down by airborne fungus. This is a slower process, so they're better off in a heap of their own. Some gardeners construct wire mesh cages and fill them with leaves, but you can also pop them in jute or plastic bags. The process can be accelerated by mowing and watering the leaves.

I don't have space for a wire mesh cage, so I filled three jute bags with leaves and popped them in my shed. The park is mainly planted with London plane trees, but these produce waxy leaves which take years to break down. So I found a few small hazels, oaks and horse chestnuts to make my mould  (horse chestnut leaves are still quite waxy, but better than nothing). The best to use are oak, hornbeam and alder.

Although the leaves will take longer to break down, I didn't water them because there were a few ladybirds among them, which I didn't want to put at risk of fungal infections over winter (watering creates the fungal conditions that help break down leaves, but it can kill insects). Neither did I mow the leaves. I left the bags open slightly so any creatures caught up in the bags could escape. After half an hour, several more ladybirds had appeared.

It's unlikely that debris blown onto a lawn would harbour hibernating insects, but if you retrieve leaves from under a hedge, or a sheltered corner of the garden, you could well be making beetle, caterpillar and ladybird mould too. Some gardeners even unwittingly pick up hibernating hedgehogs. These creatures make a great soil conditioner when dead, but most are more beneficial to the gardener alive.

There seem to be ladybirds everywhere at the moment, and I'm hoping the snug, dry conditions in my shed will make a nice hibernation spot for them. I just need to remember to leave the door open for them in spring.



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Gardeners' World Web User 06/11/2011 at 16:18

I have a eucalyptus tree that is growing in a neighbours garden that is soooo massive it overhangs the end of my garden. The main problem is all the leaves and bark that it drops everywhere all year round. Can anyone tell me if I can compost these leaves and bark or if they will make leaf mould. Not sure how they will break down as they seem to last forever. Thanks.

Gardeners' World Web User 26/11/2011 at 09:11

Oh, we laughed out loud at : “These creatures make a great soil conditioner when dead…” even though it is a sobering thought.

Gardeners' World Web User 26/11/2011 at 17:06

Makes great leafmould after a year or two in black plastic bags, Mrs. Panda. But I leave a lot under the tree for the fungi to break down and grew beautiful ferns in it. The larger bits of pink bark can be crumbled up and make great mulch for a path in my woodland walk.

Gardeners' World Web User 26/11/2011 at 17:07

Oh, and a few of the long leaves in the compost would soon go but not too many.

Gardeners' World Web User 26/11/2011 at 20:20

Nice tips Kate. I make leafmould with leaves raked off the lawn but sometimes top up with leaves from under my hedge. I’ll keep an eye out now for bugs and hogs

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