Why is mulching important?

What is mulch used for?

Mulch is used to:

• retain moisture
• contribute to soil health
• help suppress weeds
• regulate soil temperature and protect seedlings

For these reasons and more, mulching is one the best things you can do for your garden.

In temperate Australia, mulch in best applied in late winter and spring. The soil is at its maximum moisture content and fear of frost is over.

Avoid mulching in the dry heat of summer as you will prevent any water from reaching your plants and most of the soil moisture will have already evaporated.

Mulch and soil temperature

Mulch has a complicated effect on soil temperature. It is very much determined by the type of mulch material, season and climate. Thick organic mulches have a lot of air pockets and act as insulators. The result is cooler soils in summer, but that also means cooler winter temperatures.

Frost settles on mulch in winter. The mulch acts as an insulator during the day preventing the soil from warming. At night it prevents heat loss into the air, meaning colder air temperature and frost potential.

A moist, weed-free, compact soil is far more frost resistant. Counter to this, black plastic mulch in winter acts as a conductor, both heating during the day and releasing heat at night.