There is more to gardening than planting a seed and taking care of it to maturity. It needs to be looked after and nurtured. And the more we involve children the more they learn this too. One of the gardening tasks they love to be involved in is mulching. It's fun and they get to make a mess - sometimes!

I’ve been talking about the benefits of mulch for quite some time now. In terms of being a gardener, I have been a late adopter, but after using it consistently for the last 5 years, I am a convert. Especially as the climate is changing, and our summers are getting hotter. This year in Christchurch we had 5 days in a row of mid 30 degree temperatures (not a common occurrence to have this many days in a row at those temperatures). When I pulled back the pea straw at the end of the day, if I could see that the soil was still damp below it, I knew I didn’t need to water. Over that time I only watered twice as the soil had retained the moisture due to the mulch.  


What is mulch?
It’s a thick layer of organic matter that is laid on top of the soil to protect it and the plants that grow in it. The most common mulch is pea straw, but you can also use rotted down leaves, compost, bark or coconut fibre. Mulch needs to be thick to be effective – a general rule of thumb for pea straw is 10-15cm thick.

Mulch is an important element of gardening. It creates a habitat for micro-organisms, insects and worms that live in the soil, eating their way through organic matter to improve the quality of the soil. They turn the mulch and other organic matter into humus which retains moisture and turns soil loose and friable so nutrients can easily move around.

Think of the forest floor – it is never left with exposed soil. There are always leaves and flower petals decomposing on the ground. This is what we are replicating in the garden when we add mulch.

Why Mulch?
Bare soil loses nutrients and structure in adverse weather conditions.
Mulch helps:

  • soil retain moisture,
  • protects it from sun and wind exposure
  • In winter it adds a layer of protection during frosts, snow and heavy rain.
  • In summer it protects soil from the wind and sun

When I mulch with children as we come into Winter, I liken it to the blankets they have on their bed to keep them warm.  This helps them to understand that the worms, plants and soil need to be kept warm when it is cold and frosty. When we mulch as we come into Summer, I liken it to adding sunscreen and a hat to protect the worms, plants and soil from the Sun and stop them getting hot and thirsty.

A thick layer of mulch acts like an insulating blanket, keeping moisture levels more consistent, and has an added benefit – you do not have to water as often. Plants are encouraged to put down deep roots to find water which enables them to be stronger and stand up more readily to wind and rain.

Mulch also helps to suppress weeds (although compost won’t suppress as many weeds as pea straw).  Because mulch adds a thick layer of organic matter on top of the soil, weeds find it harder to grow. They use much of their energy trying to find the light as they grow through the mulch, rather than putting down strong roots making them easier to remove if they do make it to the surface.

When gardening with children the less weeds the better – we spend our time teaching them not to pull out the plants but encourage them to pull out weeds – so confusing to a young gardener!

Finally, mulch keeps your crops clean and reduces disease transfer – think pumpkins and strawberries that produce their fruit that sits on the soil as it ripens.

How to mulch
Before you put down any mulch, weed the ground first so that it is as clear as possible. Try not to dig the soil too much as this causes it to dry out and damages the soil structure – mulching over time will eliminate the need for digging.

Ensure soil is damp before adding mulch. Water well first allowing it to soak down into the soil or wait until after a good downpour of rain. Of course, children love to help water!

You will need to replenish the mulch over time as it reduces in thickness as the micro-organisms and other soil dwelling creatures munch on it. Usually, you would add a layer of mulch in Autumn after you have harvested and removed old plants, and in Spring before you plant your new season’s crops.

Get children involved
Children love to garden and laying mulch can be fun.

I have worked with many children to put pea straw around strawberries and other plants. They are doing ‘real work’ to protect their garden. I’ve observed them being very careful of the plants when they are shown how to mulch. It makes them proud and gives them an instant sense of achievement. But it’s also a time for fun – like making it ‘rain’ pea straw!

Mulching helps teach children to care for their garden in a different way than just watering plants.


If you want to know more about the contents of this blog, or would like to find out more about Growing Kiwi Gardeners and how I can help you, then contact me at This email address is being protected from spambots. You need JavaScript enabled to view it. or phone on 021 0478 844.

If you have enjoyed this blog post, why not see my post titled Soil - The key to a healthy earth where I discuss looking after the soil in order to grow healthy plants.

 Other blog posts you might be interested in:

How do we stop tamariki from pulling out plants from the garden?

Why should we garden with young children?

Education for Sustainability through Gardening