True Garden Gold: Making leafmould!
It's time for one of the most satisfying harvests of the year! Gathering up fallen leaves to make gorgeous, wonderful, remarkable leafmould
As I’m typing, our Japanese Maples are glowing with golds, ambers, and garnets. The grasses bronzing. The hostas are now a pale translucent mush. Autumn has most definitely arrived, no longer tapping on the door, but storming through and making itself at home with misty mornings, dew-laden spider webs, and the first sparkly frosts (yes, rain and wind too. Lots of rain!)
For the next couple of weeks at least, I’ll be enjoying one of the most satisfying harvests of the year! Gathering up fallen leaves to make gorgeous, wonderful, leafmould. True garden gold! In fact, I’ve already made a start by raking up the ash leaves from the Cottage Garden lawn.
The many benefits of leafmould...
As a soil improver (working via the soil life) it opens the soil structure and by bringing down organic matter it can help retain moisture.
As a mulch it helps prevent weeds from taking root and, like any mulch, protects bare soil from winter rains.
As a seedling compost mix, it’s relatively low in nutrients but rich in microbial and fungal life. The open structure is great for root development.
As a potting compost mix, it retains moisture, keeps it’s open structure, adds essential fungi and bacteria to sterile compost.
It's simply the most wonderful food for your soil biome!
The most beautiful compost
Leafmould is not only wonderfully beneficial compost, it’s also very easy to make. It’s lovely to handle too - dark and crumbly, smelling of a broadleaf woodland after the rain with a faint air of mushrooms. There is no complex list of ingredients to balance. No activators required. No turning needed. No risk of uninvited guests setting up home and scaring the life out of you when you lift the cover (yes, I'm looking at you Ratty!) Making leafmould is simplicity personified: Gather leaves, pile, and leave. Done!
Imagine how many tonnes of leaves have been cleared from gardens over the years… just to be incinerated or sent to landfill? It’s absolute madness! Why throw away a free and valuable resource when you can create a supremely beneficial, light, friable, single-ingredient sustainable compost that is astoundingly simple to make?
If you have a garden with trees and shrubs, or a garden that fills with leaves from surrounding trees, you really need to be making your own leafmould. No excuses. Thankfully, I am fortunate to have a garden with mature trees, mostly birch, hornbeam, and ash. It's also surrounded by all manner of trees from neighbouring gardens. Every autumn, I harvest all the fallen leaves from my garden, sweeping up leaves from the lane and footpaths outside. I ask the neighbours and my parents if I can collect their leaves too.
Once gathered in large garden bags, I simply pour them all into their own dedicated heap/bay - an old recycled pumpkin crate. I just throw them in and leave. No other faffing is required. The leaves decompose very slowly, through fungal decomposition, perhaps taking 1-2 years in the open. Quicker if they are bagged up. The resulting compost is outstanding! Beautiful! The spring bulbs love it, as do the spring ephemerals, ferns and other shade loving woodland plants.
Dry leaves are far easier to gather than when they’re wet, but if you’re waiting for a dry period in autumn, you could be waiting a long time, especially here in the UK! If you’re clearing a lawn, a rake works best on grass. Of course, you can buy a garden vac and other ‘time saving’ gadgets, but I rather enjoy the manual process. Especially if it is one of those glorious crisp autumn days and you can build enough puff to warrant shedding your jacket.
Slowly working around the lawn, raking leaves into piles, then grabbing two off-cuts of fencing board to scoop the leaves into garden waste bags, heaving them onto the wheelbarrow, and carting them up to the leafmould bay.
It’s a very satisfying job indeed!
On the gravel driveway and hard paths, I find a leaf blower works best. I have the basic Ryobi cordless leaf blower and it works just fine, although it sure does burn through the batteries. I methodically blow the leaves into corners or against the fence, where it’s easier to collect. You just have to accept there will be the odd stone in there.
I used to gather the leaves into rows on the lawn and ‘mow’ them up before adding to the pile. Shredding and vacuuming the leaves in one go. Although this did make finer leafmould, I’ve since learned that a number of moths and butterfly caterpillars (including the outrageously beautiful Elephant Hawk-moth) overwinter in fallen leaves, not to mention countless other insects and invertebrates - cue crushing shame and guilt. I very was surprised to read that the RHS still recommends mowing...?
But, rather than macerating leaves and overwintering invertebrates, I now make a point of only harvesting leaves from lawns, pathways, driveways, etc. and adding those leaves intact. With a few exceptions, I ignore the fallen leaves in the borders as it's a great natural mulch that will benefit wildlife and the soil biome. I’ll just remove mats of fallen leaves from low-growing herbaceous perennials and evergreens, hoping to prevent them being smothered.
How plants survive in the wild without us mollycoddling them, I’ll never know!
Having ‘put the garden to bed’ you might well prefer a pristine winter garden with clean, freshly mulched borders. But those fallen leaves provide valuable shelter and cover for overwintering beneficial insects and invertebrates that may well be devouring your aphids and slugs in the spring. Leaving some fallen leaves where they are also benefits local birdlife as they forage for meagre morsels during winter.
Once collected, I just pour my harvest of leaves into their bay - the recycled pumpkin crate. A very easy conversion. I simply levered off one side and hammered down the exposed nails, then reattached the side panel with twisted wire for easy access. I lined the sides of the crate with chicken wire and lined the base with a scrap of mesh, just to stop the leaves falling through. Everything was quickly stapled into place and it’s lasted for years. You often spot these crates piled up at the back of plant nurseries, garden centres, even builder’s merchants and they’re usually very happy for you to take them away for free.
If you don’t have room for a pile, you can bag up the leaves in refuse sacks. Just punch a few small holes in the base for drainage, tie a knot in the top and stack them out of the way and out of the sun. Behind a shed or garage is ideal.
Leafmould is created by fungal decay, so this is a ‘cool’ compost heap. It should not be hot. An open pile or bay of leaves will take a year or more to decompose, which works out fine for me as I use the previous year’s sieved leafmould for planting my spring bulbs… just around the same time I’m harvesting leaves for the next batch.
Usually, the top layer of an open leaf pile is relatively intact, looking just like a pile of dry leaves. But, just push this aside and you’ll find that wonderful crumbly compost below. As a rule, I will scoop the top layer into a neighbouring compost heap, just in case any weed seeds are nestling in there.
I sieve my leafmould so it’s easier to use in a compost mix for potting up spring bulbs. However, if I’m mulching plants in areas of dry shade, I leave it completely intact, lumps and all. If it’s been a wet summer, I will empty the entire leafmould bay, into several trugs, then store these under cover to dry out. It’s really so much easier to sieve when dry! If I'm feeling really energetic, I'll sieve it all and store the leafmould in recycled compost bags ready for use throughout the season.
Tips to try…
Try to pick a quiet day so the wind doesn’t turn your serene leaf harvest into an act of futility, or farcical comedy show for family and neighbours. If you have no choice, then rake or blow the leaves in the same direction as the wind. (It’s difficult in my garden as the wind is often swirling about and I usually give up and wait)
If you have children or pets, why not invite them out, have a giggle in the garden jumping in piles of leaves... then put the kids to work raking them up again! My dogs used to love jumping in piles of leaves. It was utter bedlam! But hilarious!
If it's a really dry season, a liberal sprinkling of water will keep the decomposition process ticking over. The drier the leaves are, the longer the process will take.
The older the leafmould, the finer the crumb! You can sieve leafmould after one year and leave the larger lumps in the pile to continue rotting down. Or use them as a mulch or soil improver. Two year old (or sieved) leafmould is perfect for potting and seed-sowing compost mixes.
Coming up…
We complete the Spring Bulb series with a look at bulb-related problems, pests, diseases, winter protection, and what to do with bulbs after flowering. Next, I’m sharing my thoughts and process for making our Kitchen Garden, including the successes and failures.
Another great article, I'm also a great believer in leaf mould and have two wire bins just for leaves!
Leaves are best added straight to beds (not the indoor ones) and borders. Maybe mown off the lawns.
That's it.