Part of every healthy garden is well-conditioned soil and the best way to get your soil in good shape is to add home compost. Composting is an essential part of organic gardening, so we have put together some tips for making compost and a list of what you can and can’t add to the heap.
What is Compost?
Garden compost is broken down organic matter. Compost is produced when micro-organisms and bacteria get to work and generate heat to decompose your organic garden and household waste.
With the right mix, an average sized compost heap (about 1x1x1m) can heat up to 70°C in just a few days. The heat generated kills weeds and diseases and speeds up the composting process. Even if your compost heap doesn’t heat up much, the material will still break down, but over a longer period of time. The finished product can take up to a year. Ultimately, what you’re after is dark brown, crumbly earth that’s ready to use around your garden to improve your soil and pay rich dividends.
Compost is a free and effective fertiliser, excellent for improving your garden’s soil and giving your plants a boost. Whatever your soil type, digging in garden compost will improve it. Compost will help your soil become easy to dig, well aerated, able to retain moisture and rich in nutrients.
What you can and can’t compost
Just about anything that will rot can be composted. Simply add layers of food scraps and garden waste materials to your compost heap as you produce them. Some materials such as cooked food, dairy products or meat scraps, although they may break down, are not suitable for home composting. However, you can safely compost these using the bokashi composting system.
Take a look at our Compost Checklist for a comprehensive list of what garden and household materials can and can’t be composted.
The perfect mix
The greens and browns of composting describes the two main ingredients used to make compost. The browns (shredded prunings, straw, most leaves, etc) are rich in carbon, and the greens (grass clippings, vegetable peelings, etc) are rich in nitrogen. As a general rule a good mix of browns and greens is needed to make compost, but for best results, aim for a ratio of 3 parts brown to 1 part green. This may not always be possible, especially if you only have a small garden, so don’t be disappointed if you’re mix isn’t exact – it will all break down in the end to rich compost.
The reason for mixing greens and browns is simple. The nitrogen in greens encourages micro-organisms in your compost heap to multiply, thereby speeding up the composting process. And the carbon rich browns contain the energy, in the form of carbohydrates, that the soil organisms need. Browns also help to fix the nitrogen in the heap, and reduce odours. In fact, besides colour, a good way to tell the difference between ‘greens’ and ‘browns’ is to see how each reacts to being wet over a few days. Greens will turn slimy and start to smell bad and browns won’t.
Having said all that, don’t get too hung up on getting the perfect mix. It’s amazing, just about anything that has organic origins will rot down eventually, so getting the ratio of greens and browns right just helps to speed up the process.