Freya ElmerFood scraps in the bin? Bit of space outside? Unused plastic or wooden box lying around? Turn all of the above into a cheap and easy backyard compost for the worms and flowers to love!
Compost bins are good for the environment by reducing kitchen food waste and providing nutritious compost to sprinkle on veggie patches, flowers or lawns to fuel growth. They also show the way simple technology can have a huge impact.
When in a bin or pile, compostable material like food scraps and plant matter start to naturally decompose by worms, bacteria and other organisms in the soil breaking down organic material into nutrient rich compost.
To be able to work, the bacteria and organisms in the soil need a mixture of green (nitrogen-rich material such as food scraps, coffee grounds, eggshells) and brown (carbon-rich material such as dry leaves, shredded paper, straw) plus air and moisture.
Follow the steps below to set up a compost bin that in three months should give you nourishing compost to use in your garden.
Build time:
1.5 hours (approx)
You will need:
- Space to put the compost bin
- Unused box with a lid (approx. 68 litres or bigger)
- Electric drill
- Material to compost
Step 1
Select a box or container (e.g. storage or rubbish bin), that is no smaller than 68 litres and has a lid.
(Tip: If you don’t have one lying around supermarkets sell a small range)
Step 2
Using a power drill (kids get your parents to help with this part), drill a series of holes 3 – 5 cm apart around the sides, bottom and lid of the container.
These holes allow oxygen from the air to circulate inside the bin helping the decomposition process. The size of the holes doesn’t matter but be careful not to make them too big otherwise the compost will fall out!
Step 3
Position the bin somewhere where the smell won’t be a problem and is easily accessible for adding material.
Step 4
Fill the bin with your compostable material. To help material break up faster make sure it is in small parts.
Most food and plant matter can go in the compost bin such as leaves, weeds, fruit and vegetable peels, eggshells, coffee grounds, tea bags, and grass clippings.
Some stuff should not go in the bin because material either can’t break down easily in a home compost (such as biodegradable coffee cups), or will attract pests (such as animal droppings or meat scraps).
See Wellington Home Compost Guide for a full list of material that you can/cannot compost
Step 5
To make sure material is breaking down the compost bin needs moisture and oxygen from the air.
Every few days aerate the mixture by turning the compost using a spade or rake, this will add oxygen and help even out the decomposition of the materials.
If the mixture is getting too wet or smelly add some dry leaves, shredded newspaper or sawdust, which will dry out the contents.
If the mixture is very dry and cold (compost should be warm, that’s the decomposition happening!) moisten with a spray bottle or add moisture rich items like old fruit and veggies to the mix.
Step 6
After three months compost should be ready to go and sprinkle in the garden.
Before sprinkling compost may need to be sifted through a wire sifter which can be bought in stores, or alternatively use a piece of wire lattice, or repurpose a kitchen sieve.
References
The Spruce, (3 Mar 2020), How to Make a Compost Bin Using a Plastic Storage Container retrived from https://www.thespruce.com/compost-bin-from-plastic-storage-container-2539493
Wellington City Council, Home compost guide retrived from https://wellington.govt.nz/~/media/services/environment-and-waste/rubbish-and-recycling/files/compostguide.pdf?la=en
