Well, I googled ‘compost definition’ and of the 2,290,000 results this seems to be the most popular.
“A mixture of decaying organic matter, as from leaves and manure, used to improve soil structure and provide nutrients.” The word compost comes from the latin compositum which basically means a mixture of different things.
So unlike soil which is really the result of rocks being slowly ground down over huge amounts of time, compost contains lots of goodies that were alive and kicking just a short while ago so to speak.
As the definition suggests compost helps our soil structure which means it can hold sandy soils together while helping clay soils to break down…clever stuff huh! It will also help to hold water in your soil, far more important than putting a layer of mulch over your patch and hoping for the best!
Another increasingly important reason to make sure your patch has regular compost added is because it increases soil biology/life. What this means is that it makes major nutrients such as phosphorous, nitrogen and potassium available to plants. That’s right, even if you keep adding fertilisers, if the soil has no life your plants can’t access it! It’s another major reason for making sure you use organic methods that don’t upset soil life.
So now we know what compost is and why it’s so important, how do we make it? There are basically two ways:
Anaerobic – this is also called cold compost, usually smellier (due to the methane produced) and harder to get the ‘right’ kind of bacteria involved. This is a common method used currently by most Australians in the form of a static compost bin such as the famous Gedeye. It’s been for as long as I can remember…check out the model’s clothes in the below picture if you don’t believe me! You can greatly improve this type of compost by circulating the contents with a compost aerator. Cold composting takes about 3 to 6 months to produce something you can use in the garden.
Aerobic – or hot compost uses a different type of bacteria which require air. This means the compost needs to be turned every few days to oxygenate the pile. Much faster, nicer to work with and the only kind I use. The downside is you tend to need to have all ‘ingredients’ on hand to make it work well. Grass is almost the perfect balance of nitrogen and carbon and will break down without much help. I usually add about 10% extra carbon material though to stop it forming into cow pats! Hot composting produces compost in around 3 to 6 weeks!
Personally I tend to put most of my organic waste through chickens and worms leaving only grass clippings to be composted. I currently use a tumble style compost bin which allows no way for rodents to enter the bin and produces compost faster than any other method I’ve tried. This is especially important to note as normally a cubic metre (BIG) is required to get a hot compost pile going.
Main problem is too rich in nitrogen, which makes it too wet and hard to move, smelly etc. Usually occurs because households produce far more ‘green’ waste than dry matter. So add plenty of straw, shredded paper etc. to keep the balance right. A sprinkling of lime will also help to decrease the acidity and make things easier on your nostrils.
How to use your compost.
Compost is ready to work into your soil when it has a sweet smell, has cooled down (in the case of hot compost) and the ingredients are almost broken down. Turn your compost into the top 20cm of your soil and leave for a week or so prior to planting new seedlings. You can also ‘top dress’ garden beds with compost, especially over winter where it won’t dry out.