How to make leaf mould

A client of mine emailed me with the following question about leaves in the garden:

"Do I need to remove all the leaves from my new borders? I have been looking for the answer to this in my books and asking people! Do you think it is just essential around my roses (powdery mildew prevention)? To remove all the leaves will be an enormous task but I am willing to try if I am likely to lose plants otherwise!"

I think this is a good question and my answer is as follows:

For those who don’t know what powdery mildew is here is a picture of a diseased plant, it is a disease that normally affects roses:

The white powdery mildew mould start off on the leaves and soon spreads to buds and other young rose shoots. The affected foliage curls up and eventually falls off if not treated. Flower buds may not open properly, and if they do, will be severely affected. So it is a serious problem and I understand why my client is worried. However, I have never heard that the leaves from trees can cause powdery mildew and think it unlikely because the disease usually appears first in the summer, particularly in hot conditions. One way to prevent it is to mulch under roses in the spring and an excellent mulch happens to be leaf mould! (A mulch is simply a way of covering the soil to reduce weeds and help retain moisture.)

Removing leaves for the borders is a waste of time because over the course of the winter the leaves rot down and act as an organic soil improver. Unless there are so many leaves that perennial plants (they are the ones that die down over winter) will unable to get any light in the spring to stimulate re-growth, let nature take its course.

Removing leaves from lawns however, as my client says, is not only good exercise but will benefit the grass. But what to do with them all? Every autumn I make leaf mould because it is an excellent soil conditioner for the plants to benefit from, and it is so simple to make. Most leaves can be turned into leaf mould, but some take longer to compost than others. Oak, alder and hornbeam will soon rot down, while sycamore, beech, horse chestnut and sweet chestnut take a little longer. Leaves from conifers and evergreen plants will take between two and three years to compost and are best added in small quantities only, shredding them first to help speed up composting. This is too much of a fiddle for me so I leave them out.

If you only have a small garden, pack the leaves tight into bin liners, or better still, recycle old compost bags. I squash them down when full by standing on them to pack more in.
Punch a few holes in the side and bottom with a garden fork. When almost full, sprinkle with water or a compost accelerator (available from garden centres ) fold over and then leave in a shady spot. The following autumn the leaves will have rotted down into a rich, crumbly mixture that can be used as a mulch around the base of plants. This is what it should look like:

Let the leaves rot down for another year if you want to use as soil conditioner.
If you have the space, and a lot of leaves to collect, buy, or make, a simple container made from plastic or wire netting with a few supporting stakes. Adjust the size to suit your requirements. Here is an example of a simple home-made container:

Leaf mould is a free gift from nature, it's easy to make, cuts out bonfires, saves using peat, is clean and easy to handle, good for the soil, cuts down on watering, can be used on any soil and finally can be used at any time of year. Do you need any more encouragement? Go out, make some and feel better as a result!