Composting 101: Everything you need to know to get started
Composting is a natural way of recycling that keeps food scraps out of landfill and returns their nutrients to the soil.
Composting breaks down food into a rich material that enhances soil and makes your garden beautiful and fruitful. It is the perfect method for getting rid of inedible food like banana and citrus peels, onion and garlic skins, capsicum cores and eggshells.
Composting requires you to have the space in your backyard and a garden on which to spread the compost. If you don’t have either of these things, there are other things you can do with your non-avoidable food waste: bokashi and worm farms.
Why should you compost?
Composting is good for the environment as it allows food to break down naturally, with oxygen. This means it does not release harmful greenhouse gases like it would do, if it was buried in a landfill.
Composting breaks down non-avoidable food waste and turns it into nutrients that can feed your garden.
What you need to compost:
- A compost bin or container
You need a container to act as your compost bin that allows the air to flow through. The size of a compost bin can vary depending on how much food waste you create; it can range from a small bucket to a larger bin measuring one cubic metre. Make sure you have a cover over the compost to keep it dry and to keep rats and insects out.
Compost bins can be purchased from hardware and gardening stores, as well as places like the Warehouse. If you live in Auckland and complete a free composting course with the Compost Collective, you will receive a voucher to go towards the cost of a compost bin. - A mixture of green matter and brown matter
We recommend using a mixture of 40% green matter and 60% brown matter.
What’s the difference between green and brown matter?
- Greens
Greens are nitrogen-rich materials such as food waste and grass clippings. They break down very quickly and will cause a rancid smell if not balanced out with browns. - Browns
Brown matter is carbon-rich material that is dry, such as paper, cardboard, woodchips or brown leaves. Browns take a long time to break down without the addition of nitrogen-rich greens.
Compost should be made in a club-sandwich style: the browns are the bread which alternate with the greens which are the filling.
Surrounding the greens with browns will decrease the smell coming from the greens, and will also speed up the decomposition of the browns. To speed up the composting process even further, the layers can be mixed at regular intervals after they have been in the compost bin for 2-3 weeks, but must always be topped with browns to keep the moisture in and the smell down.
How to compost:
- Choose a sunny spot in your garden.
- Place the compost bin directly on top of the ground so that soil organisms can get into your compost bin and help break down your compost.
- Then place sticks and twigs in the bin. This allows the air to circulate.
- Begin adding your compost to the bin with a ratio of 40% food scraps to 60% brown matter. You want to add a layer of browns first, followed by a layer of greens and finish with a top layer of browns. Tip: keep a bag of leaves next to your compost bin so as you add in your food waste you always have some browns handy.
Tip: If you chop your food scraps and garden cuttings into smaller pieces, it will break down faster and have less of a smell. Do not add any sticks that are thicker than your little finger, as sticks that are larger than that will not break down fast enough. Larger sticks can always be added to the base of your compost. - If you want your compost to break down more quickly then turn it once a week to allow for air flow through all of the compost. Use a shovel to mix the layers up.
- Once the compost bin is full, do not add any more scraps to the bin, but continue to stir it regularly. Tip: if you are not able to stir it regularly, adding in seaweed, horse manure, sheep manure or comfrey leaves will also help your compost break down faster and add valuable nutrients.
- Your compost is ready to be added to the garden when the material at the bottom of the compost bin is dark and crumbly and you can no longer identify food scraps or brown matter. This should take about 6 to 8 months.
- To harvest the compost, take the bin off the pile and place it in another part of your garden. Shovel the top two-thirds of your compost back into the bin and then harvest the bottom third. Alternatively, some store-bought compost bins have flaps that open at the bottom of the bin, allowing you to harvest the compost without moving the bin.
- Add the harvested compost to your garden to boost the growth of your plants. Dig it into your vegetable garden or add to your garden beds.
Other things you need to know:
- Compost should be moist like a sponge, so if it appears to be drying out, add some water to it. Covering the compost is the best way to keep the compost moist.
- It is also important to allow air to reach your compost; this will keep it from smelling. The best way to keep air in your compost is to stir it with a pitchfork or shovel, but be careful not to mix the uncomposted material in with the finished compost, that will slow down the decomposition rate and you won’t be able to take out your finished compost on time.
- Always wear a mask and gloves when stirring compost or adding it to the garden to minimise the risk of illness.
Things you may not know that you can add to your compost bin:
- Hair
- Pet fur
- Cardboard egg cartons
- Newspaper and photocopy paper
- Tissues, serviettes and paper towels
- Eggshells
- Droppings from rabbits and guinea pigs (any pets that don’t eat meat)
Things you should never put in your compost:
- Cooked and or processed foods such as bread, pasta and meat, unless they have been treated in a bokashi system first
- Noxious weeds – these seeds will sprout back up wherever you put your compost
- Dog or cat poo
- Oil or other liquids
