Tuesday, January 27, 2015

Let us mulch

Canterbury and the eastern side of New Zealand is in a drought and many gardens are suffering. Mulching is one easy and effective way to conserve moisture in the soil and add nutrients at the same time.

Mulching is one of those gardening activities that is often written and spoken about but not practised enough. It makes you wonder where all our knowledge and learning is leading us. Modern chemicals, artificial fertilisers, push hoes and fascination for complete neatness and tidiness has led us away from nature and natural processes.

However, don't blame the gardeners, authors and nurserymen. The large national and international companies advertise their latest product in such a way that people think that the use of these modern marvels of gardening (weed sprays, new tools, fertilisers of all sorts, watering systems and pest and disease sprays) is the only way to cope with making gardening easy. 

Don't forget also that you probably have to look at a sterile garden and listen in vain for the birds.

Mulch is an organic substance applied to the surface of the soil to perform the following functions.

  •  Adds organic matter to the soil for nutritional purposes
  •  Covers the ground to prevent weed growth
  •  Conserves soil moisture in summer to save lots of watering
  •  Protects the soil from compaction from rain and footsteps
  •  As it rots down to humus it improves the soil structure.
  •  Provides an environment for developing a living  soil
  •  Saves hours of work, weeding, spraying and tidying up 

Mulches can be various products and compost is the best. But there are other products that can be applied, sawdust, bark, wood chip, grass clippings, pea straw, straw, leaves etc. Rotted, well made compost has a balance of nutrients in it because a variety of organic materials were used to make the compost. 

However, do not let the lack of available compost deter you from applying organic substances as mulch. Properly managed individual products are an adequate mulch and provide the advantages of mulching with compost. Always leave these products on top of the spoil to rot down naturally.

Compost can be applied at regular intervals to the soil surface in layers up to 25mm thick. This is particularly good in the vegetable garden and in the flower garden where small plants or a show garden area is required.

Mulch should be placed on the surface between trees, shrubs and plants and over the top of areas where bulbs and perennials grow. Up to 100mm of raw uncomposted material can be laid on the ground. Generally, this is applied in spring but can be done at other times of the year except in very dry conditions.

This material will slowly rot down, but not all at once. The decomposition primarily occurs in contact with the soil. This is a thin layer. The rest on top acts as a protective layer to conserve moisture, protect the soil beneath and smother weeds. Often comment is made about "nitrogen lock up" when raw material, particularly sawdust, is applied to the soil. This is not true as only a thin layer is decomposing at any point in time. 

A garden regularly mulched over a number of years will be healthier and the plants will grow extremely well. The soil is healthy, soft and friable making it very easy to dig when planting new plants.

The use of mulches has a positive effect on the well being of all plants. Increased health, vigour, pest and disease resistance, flowering and seed production. Soil becomes healthier and brings the garden into a balance of nature. This leaves a lot of extra time for those enjoyable tasks of picking flowers, photography and entertaining.

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