How and why do i mulch my garden?

One of the secrets of successful gardening is the lavish use of organic mulch…
In Christchurch’s temperate climate with long dry summers every year, any measure that reduces the need for watering and saves on water is surely commonsense. Bare ground heats up very easily under the relentless Canterbury sun. Roots can’t grow in baking hot soil. Therefore in Christchurch it is essential to cover the ground with a thick insulating blanket of mulch to keep the soil temperature cool enough for the roots of newly planted plants to grow. DON’T EVER USE BLACK PLASTIC OR WEEDMAT TO COVER YOUR SOIL.

Why shouldn’t I use plastic or weed mats?

Weedmats don’t stop all weeds
Plastics and weedmats are black so absorb heat during summer which can cook the roots.
The soil can’t breath and can become very sour and wet
 Applying weedmat will double the time required to plant as you need to cut the weedmat and barrow excess soil away as you shouldn't get soil on the matting
Mulch prevents weed growth around your plants and in your gardens, but only if the mulch is clean and free of dirt. As soon as dirt is mixed with mulch it provides a “toe-hole” for seeds to germinate and become established. Don’t put any dirt on top of your mulched garden, and take particular care when planting plants that soil doesn’t get mixed with the mulch. The best way of stopping this problem is to plant your garden first then apply your mulch, Make sure your garden is raked off to a smooth finish first so no high spots poke through the mulch.
Healthy soil is alive with micro-organisms which are busy gobbling up fallen leaves and other organic matter and returning the nutrients to the soil for recycling through your new plants. Mulch provides the ideal environment for the establishment of a thriving community beneath the surface.
Once this microscopic community is established, it does one more, very important thing – it helps control root diseases.
Basically, there are two types of micro-organisms: goodies and baddies. And the goodies keep the baddies at bay. Therefore, the chance of root-rot diseases becoming established in a well mulched garden is very low. On the other hand, plants in bare ground will be stressed and highly susceptible to disease. So, for the health of your plants, mulch them!

Types Of Mulch:

Any organic mulch is OK: Pea straw, Bark, Compost, Mushroom compost (be aware this can alter the soil Ph and should be avoided around acid loving plants)  Bio blend, anything that was a plant.

Health And Safety:

Some mulches are quite dusty or contain a lot of fungal spores, so wear a mask while spreading them, and make sure the wind is blowing away from you. Once the mulch is spread and watered down, there is no more risk.

Applying Mulch:

You can either plant your plants first and then spread the mulch around them, or you can spread the mulch first and plant later. Both ways have pros and cons.
If you choose the former, be careful not to trample your plants or compact the soil as you walk around. If you choose the latter, be very careful to keep the mulch clean and free of dirt when you dig the holes to plant your plants.
Mulch should be applied to a depth of at least 75mm to ensure good weed suppression.


Thick organic mulch around your plants and over your garden beds is essential for several reasons:
Keeping the soil moist by reducing evaporation
Controlling weed growth
Keeping the soil cool
• Keeping the soil healthy by maintaing a balanced population of goodies & baddies (mirco-organisms)

Do’s And Don’ts

  Don’t use black plastic or weed mat  to cover your soil.
   Don’t dig mulch into the soil.
  Don’t use dirty mulch.
  Don’t apply mulch right up to the stem of the plants.
  Mulch your plants immediately after you have planted your plants.
 Apply mulch as a clean blanket ON TOP of soil surface.
 Wear a mask when spreading mulch.