Compost is a gardener’s best friend. It adds organic matter (humus) and nutrients back into soils, improves soil texture, increases moisture holding and generally improves overall soil and plant health.
The good news is that it's easy to make your own compost. Compost is the result of the natural decomposition of “green waste” - the non-woody parts of plants. The waste is broken down by friendly soil-borne organisms, including earthworms, in an aerobic (oxygen-rich) environment. Green waste in an anaerobic (oxygen-deprived) environment will rot or putrefy, turning into a slimy, smelly mess.
Just follow our simple steps and you'll have amazing compost to use in your garden.
Choose an appropriate position in the garden for your compost bin. A flat spot on soil is necessary for a bin or cage so the “good bugs” can move up into the waste materials you add to do their work. Compost does generate some heat of its own while decomposing, but morning sun will hasten the process. Afternoon shade is preferred so the bin or cage doesn’t get too hot. Excessive heat could kill the critters you’ve just encouraged. In among the garden foliage is the ideal spot – convenient but camouflaged!
Decide what type of compost maker you want. A traditional square compost box of timber slats that can be removed to turn or to access the contents is simple to build, while wire mesh cages, fully enclosed bins and compost tumblers can all be easily purchased.
When your compost maker is installed, you’re ready to go! There are lots of different methods of making compost, but one of the most popular is alternating layers of “dry” and “wet” ingredients (see Step 4 for what you can put into the compost). Following a structured recipe isn’t essential, so long as you use a wide range of materials and don’t add too much of one particular ingredient at a time.
Start with a layer of reasonably coarse fresh green waste (clippings or prunings are ideal) combined with a compost activator to get the process happening. Make sure it is fairly loose and no more than 10-12cm deep. Lightly cover it with a 10-12cm layer of loose dry material like pea straw or lucerne mulch.
Continue adding layers alternately. Look at the contents regularly and if it looks very dry, then lightly water. Moisture is essential. You’ll know if it’s too wet or you’ve added too much fresh material by the smell! If you are using a compost tumbler, follow the manufacturer’s guidelines for best results.
There is a wide variety of things you can put into the compost. They include:
Vegetable and fruit scraps and peelings from the kitchen (keep a container on the bench)
Crushed egg shells to add calcium (use a mortar & pestle to grind them up)
Lawn clippings that have been allowed to dry off for a week or two (fresh clippings may be too moist)
Spent vegetable and flowering plants that have been pulled out
Well-weathered animal manure such as chicken manure (sparingly)
A light sprinkle of blood and bone periodically
Clippings and soft prunings from hedges and green plants (but avoid woody twigs)
Pea straw or lucerne mulch or sugarcane mulch
Shredded paper (do not use newspaper because the ink can be harmful to micro-organisms).
Twigs and woody stems/small branches should be put through a mulcher and added directly to the garden as mulch, rather than being included in compost-making, where they may take a long time to break down, while mulch and shredded paper should be used in moderation.
Please also remember what you should not put into compost. Anything of animal origin that rots, putrefies or attracts rodents and flies or is not readily decomposed by soil micro-organisms, including:
Meat or fish (raw or cooked)
Cooked food waste and table scraps (salad vegies are OK)
Dairy products (cooked or raw)
Cooking oils and fats
Fresh animal manure (including cat and dog poo)
Aerate the compost occasionally with a garden fork. Lift and loosen the contents of your bin or cage to reduce compaction and ensure everything is breaking down rather than rotting. While not essential, turning over will mix the materials and produce a more uniform end product.
Compost should have an earthy smell, never unpleasant or odorous. A couple of handfuls of garden lime every few weeks will help keep the compost “sweet” (not too acidic).
Continue adding more mixed waste until the bin or cage is comfortably full, then leave it to “mature” for a couple of months, checking the moisture content occasionally to ensure it doesn’t become too dry.
It’s a good idea to have a second bin or cage ready to go when the first one is full and maturing, so you can have a continuous supply of goodness for the garden.
The end result some three to six months from starting should be a rich, dark, sweet smelling “soil” that your plants will love you for! Add it to the vegetable patch in preparation for planting or spread it around growing plants to improve the quality of the soil and give them a nutrient boost.
Fruit and vegetable scraps from the kitchen
Pea straw or lucerne mulch or sugarcane mulch
Compost bin or cage
Compost caddy or alternative like an ice cream container with lid