Other methods

Other composting methods

There are several ways of making compost, and you need to choose a method that works best for you.

Trench composting

This is very easy, if you have the space and patience. The advantage is that microbes already exist in the soil and give the composting process a bit of a head start. The disadvantage is that it is harder to compost larger garden materials and it takes longer to compost. Dig a trench 30-40cm deep, 30 cm wide and as long as you like. Add compost materials (food waste etc) daily and cover lightly with soil. The area can be planted over after 12 months, or compost dug out between 9 and 12 months.

Compost bins 

Available from many hardware stores. A contained bin will keep rain out, retain heat well, prevent the ingredients drying out too much, especially at the edges, and keep the area looking neat and tidy.

Layered heaps

A simple method building a heap over time (see diagram) Start the heap off by using larger branches and twigs as a base, - this will let air in and allow for good drainage. Then you can start layering your waste materials – layer of food, layer of grass cuttings, layer of twigs, layer of food, etc. It is worth occasionally adding a layer of soil, which will contain many of the microbes necessary to get your compost working. Make sure the compost has a cover of carpet or similar during wet periods so that the compost doesn’t get too wet. Works best if at least 1m2.


Effective microorganisms, bokashi: a fermentation rather than decomposition process, using EM is helpful in confined spaces and multidwelling units. Although the fermented product looks very much like the original product (think of a fish still looking like a fish, but certainly not smelling as a dead fish would!) – the decomposition in a standard composting system or trench system is very much quicker.

Handy hints for composting

  • Set up a separate bin in the kitchen for food scraps, tissues and handtowels. A four litre pail with lid is a good family size.
  • If you are concerned about adding weeds to your compost, ‘cook’ them first in a black bag left in the sun for 2-3 weeks. You can then safely add the materials to your compost. It’s probably wise to avoid cooking or composting really nasty weeds like oxalis, wandering jew, convolvulus and couch and kikuyu.
  • It takes anywhere from 2 – 6 months to make compost. The greater the surface area of the material, the quicker compost is made, so you may want to chop up food wastes and run the lawnmover over larger twigs and small branches.
  • Be careful about adding thick layers of grass clippings in one go – they tend to mat together and not allow air in for decomposition. Thin layers of grass cuttings are very beneficial to a compost heap as they act as an activator to get the beneficial microbes working.
  • Thin layers of grass clippings also act as a mulch, so feel free to use them on your gardens.
  • In the time it takes to make compost, the material shrinks to about 1/5th of it’s original volume.
  • The hotter the pile, the quicker the decomposition, - though pile should not exceed 70 degrees C.
  • A large compost heap will insulate itself, - though if too large, not enough air will reach the microbes at the centre of the heap. At least 1m2 is good.
  • The heap should be as moist as a wrung out sponge, -neither too wet nor too dry.
  • Turning the compost heap distributes air, water and materials through the heap and allows the outer material an opportunity to decompose.

Fixing composting problems

The compost heap smells bad:

  1. Not enough air – poke sticks through it to create air passages or turn it.
  2. Too wet, - add dry straw, twigs, shredded paper/newspaper, leaves, soil

The compost heap is too dry:

  1. Add soft green material from kitchen
  2. Add thin layer grass cuttings
  3. Add water – compost should be as damp as a wrung out sponge.
  4. Turn heap, or increase size of heap to at least 1 cubic metre.

The compost heap is too cold:

  1. Turn heap and add nitrogenous (green) materials like grass cuttings, vegetable scraps.
  2. Add poultry manure, animal manure or blood and bone.

need to link to diagram of compost heap