Composting isn’t complicated — it’s a key part of a healthy garden. This step-by-step guide covers the basics of compost bins, the difference between hot and cold methods, and simple tips for turning garden and kitchen waste into rich, usable compost.
The 2025 Autumn Gardening Series is supported by Gubba Garden Store.
There is no better time than autumn to get started on a compost pile. As the daylight hours dwindle and the temperatures drop, you’ll notice the garden shedding all signs of summer.
The leaves on the trees turn amber while the flowers blacken with seed heads, and we are compelled to ‘tidy up’ and put the garden to bed for winter. Amid this, we are consequently left with piles of prunings and deadheads which, if treated appropriately, can be transformed into garden gold come springtime.
Composting shouldn’t be seen as a daunting task, but rather an integral part of a flourishing garden. The trick to success with your compost pile is by simplifying it.
Compost bins
The simplest way to compost is to use a simple and purpose-designed compost bin. Many bins are a practical solution for small gardens where a ‘compost bay’ is not possible due to lack of space. While these bins can be a bit of an eye sore, if tucked behind a garden shed or fence, they are ideal for beginners who feel intimidated by a traditional pile.
Choose a compost bin with a strong, secure lid and can be rat-proofed by adding some reinforced steel mesh or chicken wire down the bottom and securing with cable ties. Rats can be a common problem and are usually one of the biggest hurdles for people when it comes to composting, so taking this step can make all the difference!
How to use a compost bin
Compost bins function like a giant soup pot – add in the ingredients (brown and green waste) and stir it until it breaks down.
There are two ways you can use a black compost bin:
Cold compost
Add ingredients gradually as materials become available.
This is the preferred method by many as storing materials can be difficult if you don’t have the space. This method is perfectly fine, especially if you are just trying to minimise your food waste and don’t intend to use the compost you make quickly.
The cold composting method takes a lot longer to produce usable compost but is a good way to continually break down the materials around your garden throughout the year.
Another point about cold compost is that because the pile doesn’t heat up quickly, you must be careful about what kind of food you put in. Meat, dairy and citrus can attract rodents and take a long time to break down in the bin.
Hot compost
Add ingredients all in one go.
This process is much faster to break down the materials. You can collect bags of brown waste like leaves, wood chips and paper waste and store in an area like a garage or shed.
Designate a wheelie bin outside for green waste, like clean garden prunings and lawn clippings. Food scraps can be fermented inside a bokashi bin until you are ready to use.
Turning compost with a corkscrew ‘aerator’.
Bokashi food scraps, ready to go into compost bin.
How to: Hot compost for beginners
1. Collect materials – brown waste = dried leaves, paper waste, wood chips + green waste = lawn clippings, garden waste, bokashi.
2. Store in bags / bins until you are ready to build the pile.
3. When you’re ready, start by adding a good layer of wood chips. This will help with drainage.
4. Then begin to layer the green and brown waste until you have reached the top.
A good ratio is 40% green and 60% brown. If you don’t have enough greens your pile will fail to heat up but if you don’t have enough browns there will be lack of airflow and structure.
5. Add a bucket full of water into the bin at the halfway point, and once again when you reach the top.
6. Keep pushing the materials down as you build the pile. The pile won’t heat up if the volume of materials is too low.
7. Once full, close the lid and wait a few days.
8. After three days, use an aerator to turn the pile. This will be difficult the first time you do this as the bin is so full and compacted. Go slowly and take your time.
9. A week later, check on your bin. The materials should be a lot more condensed and looking broken down. The pile should also be steaming – this is a good indication you have made a hot compost pile.
10. To keep the temperature up you must turn the pile again.
The purpose of turning the pile is that the centre will always be the hottest, so you must move the cooler materials on the outside into the middle. This also helps to add oxygen into the pile.
11. Keep turning every few days from now on until the pile stops heating up.
12. Your pile must remain at a high temperature of 55 degrees for 1-2 weeks to kill pathogens and weed seeds.
13. Once the temperature of the pile lowers, leave to cure for 12 weeks. This is an important step as using hot compost too early can risk burning your plants.
14. When worms return to the bin and soil appears crumbly and loose you may use the compost in the garden.
This is when having two bins comes in handy, one can be left to cure while you build the next one.
Worms returning to the compost bin means it’s ready to go onto the garden.
The Autumn Gardening Series is proudly supported by Gubba Garden Store.
www.gubba.co.nz | @gubbagardenstorenz
