What is mulch?

Mulch is a layer of material, organic or inorganic, that is spread over the surface of your soil to help lock in moisture and to help save water. It is often neglected in gardens, but is very beneficial if used correctly. If you think of an indigenous forest with its layers of leaves, sticks and twigs, and how organic the soil on the forest floor is, then you’ll begin to appreciate the benefits of replicating this environment by using mulch in your garden. Apart from water-retention, mulch has additional benefits such as reducing the growth of weeds, and preventing soil erosion.

Here are some of the materials you can use:

  • Organic materials
    Organic materials slowly break down and help to enrich your soil. You can use dry leaves and twigs that are naturally found in your garden – instead of throwing them away – or visit your local nursery and purchase bark chips or nut shells. Macadamia nut shells are popular and an excellent choice, though both these and bark chips can be fairly expensive if you’re trying to mulch large areas. Apply a layer about 5-10cm metres thick on top of your soil.
    If you’re looking for more colour, you could also use a groundcover as an organic substitute. Try plectranthus or hen ‘n chicken’s (Chlorophytum comosum), both of which spread easily and quickly.
  • Inorganic materials
    Inorganic materials don’t break down, so they last a lot longer. You could use pebbles or gravel, both of which can be found at your local nursery. Be careful though with inorganic mulches, as they tend to heat up and raise the temperature of the soil. To avoid this it’s often better to use them in shady areas (preferably under evergreen trees where there will be fewer leaves falling), or around plants with low-water requirements. The benefit of inorganic materials is that you can choose your colour, so choose one that matches your garden theme.