THE last of this season’s autumn leaves are about to fall, adding to the now soggy layers already on the ground.
In many gardens these will end up in council recycling bins and converted into commercial compost. But why waste this valuable resource when – at very little expense – it is easily recycled into leaf mulch, potting mix improver or compost and used in your own garden?
QUICK AND EASY
The easiest option is to rake the leaves together while they are damp. Then put them in a heap out of the way (behind the toolshed, under a tree canopy) where not exposed to wind and where possible protected from soaking.
Then they can moulder away over winter.
By mid-spring the leaves should have started to decompose. While the content of the heap may look like a soggy, matted mess, rest assured the resulting material is ideal for mulching, particularly when spread between rows of newly planted vegetable and flower seedlings. Leaf mulch is also ideal for mulching fruit and ornamental trees growing in large containers.
Trials have shown how a 2-3 cm layer of leaf mulch applied early in the growing season can reduce water consumption in the vegetable garden by 30 to 50 per cent.
POTTING MIX IMPROVER
Autumn leaves by themselves contain very little in the way of essential plant nutrients, particularly nitrogen, phosphorus and potash. However, their nutrient content can be increased significantly simply by soaking them – before they are heaped – in slurry made from aged animal manure and water.
Chicken and cow manures are ideal and are readily available by the bag from garden outlets.
Place 10-15 litres of manure into a large plastic container (rubbish bin, wheelbarrow or 40 litre PVC storage bin). Add 15-20 litres of water, agitate to make slurry and start dunking the leaves. If possible keep the leaves together by surrounding the resulting heap with chicken wire or PVC fencing mesh (looks more attractive than chicken wire).
Alternatively, a less messy option is to buy a 1 litre bottle of liquid organic fertiliser and use this at four times the recommended mixing rate. Allow each batch of leaves to soak in the solution for at least 30 minutes.
Note: Make sure the leaves are fully decomposed before using them as an additive to your potting mix. As a guide, they should make up about 15 per cent by volume of the overall mix.
THE BEST OPTION ... COMPOST
Compost is very different to leaf mulch, where the plant materials being used are still in a semi-decayed form.
With compost, the materials are completely decomposed by myriad naturally occurring soil microorganisms. In their wake the microbes leave behind soft black or brown moistureabsorbing material known as humus. However, the quality of your compost is very dependent on the nutrient content of the materials you use.
Quality compost is made by gathering spent vegetable and flower plants, lawn clippings, green weeds and, if possible, aged animal manures, and blending this with dried leaves, chopped prunings, dried grass and straw.
The best quality compost is made when the heap you produce is at least 1m high and wide. This ensures the heat generated by the composting process is retained as this speeds up the process of converting these materials into compost.
Chop chunky materials into small pieces.
Use a range of materials but limit any single material to 30 per cent of the total volume. Make sure the materials are wet before placing them in 1530cm layers.
Keep individual materials in separate piles until you have enough to produce a cubic metre heap in one operation.
Jon Lamb writes a Good Gardening email at gardenand outdoorliving.com or facebook .com/jonlamb good gardening