Claire Mummery: The secret to mulching your plants - which mulch to use and why

Mulching means adding a protective layer to your soil, and is such an important part of gardening. Photo / 123RF

One of the best ways to maintain healthy plants during the hot summer is to mulch them.

So what is mulching and why is it important?

Mulching means adding a protective layer to your soil, and is an important part of gardening. It keeps the moisture in your soil and keeps the plant’s roots cool. It even helps keep the weeds down. A good mulch can reduce the amount of water your plants require, as their roots will go down to find the moisture that has been retained deep in the soil.

As we head into the hot summer months, a light-coloured mulch is best because this reflects the heat of the sun and will keep the soil underneath cooler. A cooler soil will retain more moisture.

Mulch is ideal to stop splashback from the soil, when heavy rain hits which can weaken plants and cause rot or disease.

What kind of mulch should I use?

Mulch comes in many different forms. In most garden centres, pea straw is readily available in bags or, for a more economical supply, you could search the internet for a pea straw supplier and buy a bale. You could visit a store that sells horse supplies and buy a bale of normal straw, which will go a long way and allows you to put a thick layer of mulch around your plants.

Sadly, neither of these sources are organic and some have been heavily sprayed, especially pea straw, so keep that in mind.

A simple and accessible form of mulch is grass clippings that have been carefully laid out and dried. Spread the lawn clippings out in a thin layer to dry as soon as the lawn has been cut, turning daily for about three days. Store once dry and use around your plants as needed. If you don’t have a lawn, you could ask a contractor or a neighbour for their clippings, as most of this valuable resource is sent to the dump.

A word of warning here - never put fresh grass clippings onto your vege garden, as this can burn your plants and stunt their growth. Freshly cut grass heats up very quickly in the process of breaking down. Fresh grass clippings can be put on top of cardboard around your fruit trees, but never close to the trunk.

You can also use bark or sawdust, remembering that sawdust should be left for a while first, as it can be quite acidic for the garden and leaches out the nitrogen in your soil. Having said this, it makes a great mulch source for blueberries, which love acidic soil.

Strawberries can be mulched with pine needles, and they’ll thank you for it.

Dried leaf mulch makes another free option, either as a layer of shredded leaves or leaves that have been collected from a previous season and allowed to partly break down, which will enrich your soil in many ways.

Failing all this, you can use shredded paper or wet cardboard to protect plants, then cover with dried leaves to hold it in place. Cardboard is great to put around crops that will be in the ground for a long time, and also around fruit trees - especially citrus - as their feeder roots are very close to the surface.

The most important thing to remember is to make sure you leave a breathing space around the stem or trunk of your plants. This enables essential airflow and prevents a microclimate forming, where pests and diseases can breed. It is also a great space to water your plants directly into the soil in the earlier, cooler hours of the morning.

Mulching your garden will enable continuous growth in the summer months, as your plants thank you for the cool, moist soil you have given them.

For more gardening advice, visit growinspired.co.nz and discover Claire Mummery’s online gardening course at www.growinspiredacademy.com