COLOURS of crimson, yellow and burnt orange adorn the fall garden thanks to September's sunshine that encouraged trees and shrubs to produce a heavy fruit set and blazing fall colours.
Now that the colours of fall are dropping to the ground, we run into the age old problem of what to do with all those leaves. Aside from piling leaves up and playing with the kids, the usual practice of rake, blow and go will probably begin in earnest. However, all that leaf biomass has value in the garden and perhaps in this age of sustainability we should look at recycling leaves at home instead of hauling them to the transfer station.
The simplest way to use leaves at home while saving money is to apply the leaves as mulch. I know many people will dismiss this idea instantly as being hippie guru stuff, or simply not attractive enough for my garden. But I ask you to at least consider the benefits of leaf mulching in the garden. Reusing leaves at home will at a minimum save tax money by reducing the volume of green waste that goes to the transfer station and everyone wants to save tax money. Using leaves as mulch will also save money by reducing the amount of mulch that has to be bought to protect the soil from the ravages of winter rain and frost.
Beyond those monetary benefits, leaf mulching is beneficial for soil fertility because it attracts worms, bacteria and fungi to a palatable food source which those organisms turn into organic matter that's rich in nutrients. Not to mention the fact that leaves protect the soil from rain compaction and leaves make a lovely sound as the rain splatters among them.
The primary problem with using leaves as mulch comes down to presentation quality. Presentation standards are usually a matter of perception more than anything. So maybe we need to change our perception of what a healthy garden looks like. To use leaves as mulch they simply need to be processed a little to alter their shape and texture to make them look more palatable to our perception.
Some leaves like Japanese maple, birch, katsura and many other small leaves do not require any alteration before use. Their size is compatible with what our eyes perceive as orderly. The trick to applying small leaves comes in the form of focused application in a uniform manner that produces a level and orderly looking bed surface. It takes some effort but the benefits are many, including a tapestry of colour and texture that few other types of mulch can match.
For large leaves like bigleaf maple, Indian bean tree, cherry, magnolia and so on, the trick is to process them a little bit by piling them on the lawn and running over them with the lawn mower to shred them up and unify their size and shape.
Once shred-processing is done, large leaves can be applied like any other mulch. I know everyone is thinking that's a lot of work, but so is raking, piling, hauling and unloading at the transfer station. And leaves are free and it takes less time to shred and apply leaves versus loading, hauling and unloading them at the transfer station.
Another excellent use of leaves is to build a leaf-compost pile. Leaf composting produces high quality compost called leaf mould, which is black, rich, earthy and full of nutrients - and free.
To build a leaf compost choose somewhere in the yard where the leaves can sit and decompose for six to eight months. Begin by levelling the site. Start piling the leaves in an orderly and stacked fashion, thicker on the outside edges and slightly thinner in the middle of the pile. Build each layer 30-40 centimeters thick (12 to 16 inches). On top of each leaf layer, add a nitrogen accelerator to feed bacteria that will break down the leaves.
This is one of the few times I recommend additives. Use 210-0 about one to two handfuls per square metre - any more is wasteful. On top of the additive, apply six centimetres (2 inches) of any garden soil to cover the leaves.
The soil will bind most decomposition gases and provide bacteria to break down the leaves. Continue this procedure over and over until you build the maximum length, width and height you desire.
The pile should form with sides gently tapering inward to keep the pile upright but not in a pyramid form. The top layer should be soil only and perhaps a piece of cardboard if you are worried about heavy rainfall, but it's not absolutely necessary.
A little leaf in the garden beds and some leaf compost in the corner is good for the wallet, body, soul and the environment.
Todd Major is a journeyman horticulturist and chief horticultural instructor at the University of British Columbia Botanical Garden. For advice contact him at [email protected].
