Autumn leaf mould compost is ideal for seedlings and for soil aeration

Kitty Scully advocates scooping up the bounty of autumn for leaf mould compost which she says is ideal for seedlings and for soil aeration.

AS autumn gives way to winter, daylight and temperature levels plummet and decidious trees respond by surrendering their definitive green coloured leaves for brilliant shades of yellow, orange and red before eventually falling.

This multi-coloured leaf drop is a survival mechanism for trees as they avoid winter stress and slip into dormancy. Furthermore, leaves evenutally become a free source of organic matter and mulch for that tree.

However, if leaves are falling on your driveway making it dangerously slippy or blanketing your lawn, you may be looking for a survial mechanism to deal with them.

If so, making leaf mould is the ideal fix. In deciduous woodlands, leaf mould and autumn mulching occurs naturally as fallen leaves are left undisturbed and over years form a thick layer on the forest floor.

If you dig through the layers you would soon discover the rich, dark brown crumbly material that is leaf mould. As an organic gardener, one aim is to imitate natural ecosystems, however,

I am not encouraging you to raid woodlands for fallen leaves. Instead gather leaves from your own garden and transform them into a salubrious soil conditioner.

Leaf mould is not particularly high in nutrients but instead makes an excellent soil conditioner. It can be dug into garden beds to improve humus content, which in turn will improve soil structure and water retention. This water retaining ability also makes it an ideal mix for use in containers.

As a mulch or top dressing, leaf mould looks great on perennial and vegetable beds and will release some nutrients to the soil over time. Very well-broken down leaf mould (more than two years old), can be sieved and used as seed-sowing compost, or mixed equally with sharp sand, garden compost and good quality soil, for use as potting compost.

One of the only negatives about leaf mould is that it requires time, taking at least 12 months to decompose. Since leaves are mostly made up of carbon, they take a lot longer to break down than nitrogen-rich materials such as grass clippings. Leaves break down by the activity of fungi, which is a slower and non-heat dependent affair.

In a compost heap, it is the heat generating bacteria that are doing all the hard work so it is not a good idea to put autumn leaves in your compost heap as it will slow the whole process down. Instead, keep these fallen leaves in a separate heap or bin.

All leaves and conifer needles will break down into leafmould, with different leaves having different qualities and breaking down at different speeds. Some leaves, such as oak, beech and hornbeam, break down with little assistance and make the best leaf mould.

As a rule of thumb, thicker leaves such as horse chestnut and sycamore are slower to decay as they have more veins. You could shred leaves with a lawnmower before adding them.

Conifer and pine needles make an acidic leaf mould which is ideal for mulching ericaceous plants, such as blueberries, azaleas and camellias and therefore should be kept separate from broad leaves which are richer in potash and phosphorous. Evergreens with waxy leaves, such as holly and laurel should not be included.

Be careful if you are gathering leaves from public places as firstly you may need permission and secondly, wear gloves as you may find unwelcome pieces of glass and other refuse mixed through.

A simple leaf mould container can be made by with four wooden posts and chicken wire. You could place it under a decidious tree, as this ensures it has some overhead shelter and leaves may fall in directly. Pack as many leaves as you can into the container as the pile will rot down into a much smaller volume.

Thoroughly dampen the pile as it encourages fungal breakdown. Check the moisture level occasionally during dry periods, adding water if necessary.

In addition, turn it regularly to aerate the leaves and speed up the breakdown process. If you don’t have room for a bin, stuff black bin bags full of moist leaves and tie securely. Best label bags for fear they get carried of as rubbish!

Cut several holes in the bag to allow for aeration and check the bag every month or two for moisture, adding water if necessary.

Once leaves are gathered, there is nothing much more to be done. It should take at least a year if not longer to break down and for your pile of soggy leaves to have magically transformed into a dark and crumbly, almost peat-like, enriching soil conditioner.