| Compost
Reasons for making Compost.
Sustainable gardening seeks to provide the best conditions for optimum plant health with the smallest possible impact on the environment.
The plants in our gardens need a constant supply of nutrients in order to grow and provide us with a pleasant environment in which to live, or nutritious food to eat.
One of the cheapest and most environmentally sound ways of achieving this is by recycling household and garden waste to make compost.
When we set out to do this we are decreasing the amount of waste we send to council tips and landfill and fertilizing our gardens at the same time.
Compost is a balanced way of enriching and improving the health of your soil and encouraging the growth of strong, healthy, disease resistant plants.
What is Compost.
Compost is quite simply a method of speeding up the process which nature uses to make humus on the forest floor, where the constant renewal of the leaf layer and the shade created by the forest canopy, provides the moist conditions required by the microorganisms necessary for the breakdown of organic matter.
Decomposition is the result of digestion and redigestion by a complex ecology of microorganisms, insects and worms which require both air and moisture to transform crude vegetation into humus.
Humus is a very important form of decomposed organic matter, a complex mixture of substances and the last stage of the decomposition of organic matter. The soil chemistry of humus varies according to the types of organic matter, the soil organisms involved and the environmental conditions involved in humification. Brown or black in colour it has a light crumbly texture when dry, holds several times its own weight in water when wet and has a fresh “earthy” smell.
Temperature fluctuations in the soil are relatively small compared to atmospheric changes and the soil animals are rapidly killed by dry conditions.
Mulching in summer gives protection to soil life and improves the viability of soil.
Most soil animals are oxygen breathers and cannot live in poorly drained and compacted soil.
Making Compost.
Compost can be made in heaps, wooden bins, plastic bins or compost tumblers, much depends on your proximity to neighbours, the size of your garden and the amount of compost you require.
Compost can be made aerobically (with air) or anaerobically (without air).
The most popular method of making compost is aerobic.
Keep pets away, pets and compost don’t mix.
Don’t add perennial weeds or seeds, or plant residue which is diseased.
Meat and bones become smelly and attract flies and rodents.
Glossy paper has chemicals in it and is best avoided, newspaper, shredded or torn is fine.
Worms dislike onions and garlic.
Materials for Compost.
Most average households accumulate enough organic materials to make sufficient compost to supply garden needs.
The most important factor is to balance the ingredients in your heap, that is the carbon/nitrogen ratio.
High carbon materials are the dry, woody materials and the high nitrogen materials are wet and green.
The microbes in your compost heap need a ratio of about 30 carbon to 1 nitrogen in order make body mass and multiply.
A word about some common materials…
Weeds… when green provide nitrogen
Banana skins…rich in phosphorus, potassium and nitrogen
Leaves…low in nitrogen, rich in minerals, slow to decompose unless shredded or ground with a lawnmower.
Hair… high in nitrogen, feathers have similar qualities.
Dust from the vacuum cleaner
Grass clippings…high in nitrogen, need to be mixed with leaves or straw.
Kitchen garbage facilitates the decomposition of other materials.
Animal manure…fresh manure contains large amounts of active digestive enzymes and cellulose decomposing bacteria, which speed up heating and decomposition.
Blood and bone…high in nitrogen, speeds up decomposition
Lime or Dolomite…prevents odours, can speed the decomposition process. Azobacteria, that fix nitrogen in the compost are dependant on the availability of calcium.
Calcium is an important soil nutrient essential to the formation of plant and animal protein, however if your soil is very alkaline then it is not necessary to add lime or dolomite to your compost.
Lucerne hay… lucerne is a perennial legume which draws on subsoil minerals.
Pea straw, hay and straw….nitrogen and carbon.
Coffee grounds…nitrogen, phosphorus and potassium, attract worms and prevent odour.
Building the Heap.
Materials available for compost will vary in most backyard situations however it is important to remember the nitrogen/carbon balance if you wish to produce good compost.
The smaller the particles in your heap the quicker the decomposition, you can use a lawn mower to chop your materials or use a garden mulcher.
You can still make compost without these gadgets it will just take a little longer!
The correct moisture level in your heap is very important, too wet and you will have foul odours and a slimy heap, too dry and bacteria and fungi die, and decomposition will come to a halt.
Compost with the correct amount of moisture should feel very damp when squeezed but you should not be able to extract much moisture.
Turning the heap regularly supplies oxygen for the aerobic bacteria and hastens decomposition, the outer layers are distributed through the heap, the materials which have slumped and softened are fluffed up and recharged with air.
If you cannot turn your compost do not despair you can still make compost without turning your heap it will just happen more slowly.
If your pile has dried out turning and watering the layers will start the process of decomposition again.
It is important to cover and protect your heap from heavy rain. A wet slimy heap quickly becomes airless and chilled and valuable nutrients can leach away.
The addition of carbon materials throughout the heap will ensure the even distribution of moisture and get your heap going again.
The best size for your compost heap is 1.5m wide and 1.5m long and at least 1.5m high. Smaller heaps will not heat up as well with the exception of the compost tumbler which is a rotating drum that can be turned frequently thus improving aeration and speeding up the process of decomposition.
It is best for making small “one off” batches.
Probably the best method is to have at least two bins one filled and heating and another gathering material ready for building.
Plastic compost bins while not very large are best suited to people in urban situations, however decomposition can take a long time if the C/N ratio is not correct, or material comprises large resistant material like stalks and prunings.
Heaps should be open at the base to enable worms and other soil life into your heap.
Place some large stalks at the base to ensure airflow build your heap in layers using your high nitrogen and carbon materials and moisten between additions if your material is too dry.
Finished compost can be applied directly to the soil, be sure to cover with mulch to protect your valuable humus.
VISIT THE NURSERY SITE TO SEE A COMPOST HOW TO VIDEO
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