Compost is for everyone

Published: 10 May 2023
Man holding a shovel full of soil.

Compost does not need to be complicated or expensive. That’s according to Max Godber of Living & Learning Pakenham, one of several neighbourhood houses in the Cardinia Shire.

He coordinates volunteers and activities in the community garden, and one of his projects is setting up a community compost hub. He sees compost as both a no-brainer and an opportunity.

“The small steps that we can take as individuals and residents in a town or in a city will make an impact,” Max says.

“Especially if we increase those opportunities for people to have that choice to put food waste somewhere where it will not only be recycled locally, but then the benefits of this nutrient-dense compost will also be used in building healthier and more fertile soils in local community gardens.”
Max Godber

To spread the composting gospel, Living & Learning Pakenham has teamed up with Cardinia Shire Council and Swinburne PrimeSCI!, a science-based outreach and education program that goes into schools and delivers on the ground workshops.

Supported by a grant from Sustainability Victoria, The Community Alliance for Waste Reduction and Sustainability was born to fulfil a shared goal of diverting waste from landfills and supporting community resource recovery.

What makes compost so great

Food waste that goes into landfill contributes to greenhouse gas emissions.

“I think when we put things into the rubbish bin, it goes out of sight and out of mind,” says Max.

“We don't consider the implications and the environmental cost that landfills are contributing to. And food waste represents at least 40% of what is sent to landfill.”

Composting destroys weed seeds and pathogens. It also stabilises carbon and nutrients so that they are released in a controlled way to feed both the soil and plants.

When compost is added to soil, native soil organisms – from the tiniest bacterium to an earthworm – respond to the sudden increase in food.

The soil ecosystem grows, and the soil organisms evolve, forming associations with plant roots, reconstructing collapsed burrows, making new niches in the soil to hide and breed in, and processing organic matter in the compost towards humus.

Not to be confused with the Middle Eastern dip made from chickpeas, humus is the ‘gold’ in the soil and the backbone of soil health. Not only does it improve aeration and drainage, but it also boosts water and nutrient holding, provides slow-release food for soil organisms, and it gives healthy soil its dark colour.

The elements of good compost

Compost needs organic materials in the right proportions, and it needs to be aerated or turned to give it oxygen.

It should have a 50:50 ratio of green to brown ingredients by weight. Green or brown materials relate to the amount of nitrogen (green) and carbon (brown) in the starting blend.

Green materials generally have higher levels of available nutrients, which the microbes use to break down the more resistant components in the brown materials.

Food organics are generally regarded as green because of their higher nutrient content. Woody materials like paper, cardboard and dead leaves are examples of brown materials.

How to start

“I’m a big fan of DIY,” says Max.

“And I’m also a big fan of using what you’ve got.”

Max believes composting doesn’t need to be complicated, either.

“Start with something easy. You could go with a compost tumbler, and you can make those out of a 44-gallon drum, with a simple stand.

“We recommend at least one cubic metre of space in your compost bay. That allows the compost pile to generate the heat sufficient to kill any noxious weed seeds, or any seeds in general, and also to kill any pathogens that may be present.”

Then you can use pea straw or rice chaff.

“I wouldn’t recommend using hay but don't go out of your way to find a dry material to use as that carbonous content. Use whatever you have,” says Max.

The best dry matter for your compost is wood-shavings that have come from non-treated wood, according to Max.

“I prefer wood-shavings over sawdust because there's a bit more substance to it. Wood-shavings is my silver bullet for managing a healthy compost bin.”

Max says incorporating newspaper and other shredded paper will contribute to your wet portion of the compost, so use it accordingly and in the right proportions.

Then it’s about adding your FOGO and turning the compost to aerate it.

A person holding soil.

How to keep a healthy compost going

Compost lives or dies based on moisture and temperature management. Composts need to start off with a high moisture content of around 50 to 60%.

When grabbing a handful of blended material, you should get some water running out between your fingers when you squeeze tightly. No water means the mix is still too dry; too much water running out means it’s too wet. If your compost bin smells, that also means it’s too wet.

Oxygen is introduced into the mix by turning the compost. And you need to have enough dry material to keep it airy.

Max says you should be able to put your hands in your compost bin and, even if it’s not finished, you should be able to pick it up and it should be spongey and sweet-smelling.

“If it smells too acidic, it means that there’s been too much nitrogen-based material and not enough carbon-based material,” Max says. “Compost should smell sweet, and if you’re doing it right, it shouldn’t have a bad odour at all.”

The Australian Standard for Composts, Soil Conditioners and Mulches says composts should reach a minimum temperature of 55ºC for 3 days before being turned. It ensures the cold outer material is folded into the pile so it can also be heated.

This process should occur 5 times to ensure all parts of the compost are equally pasteurised. Pasteurisation happens when all materials have been exposed to high temperatures. This exposure takes care of weed seeds and pathogens, making the compost safe to use.

A mature compost can take 12 to 20 weeks. Mature compost is special because of its humus content. After enough time in a compost pile, a large proportion of the fresh organic material has been transformed into humus.

What to avoid

Max recommends leaving products like meat, fish, or cooked rice out of your compost.

“If you are going to put in bread, break it up, and don't make it your biggest percentage of food scraps going in,” he says.

It’s also best to avoid putting in eucalyptus leaves.

“But if you do have eucalyptus leaves, leave them to dry before adding them in. Fresh or green eucalyptus leaves has oil that will deter worms and the micro-organisms that are the real the compost makers.”
Max Godber

Composts made with high proportions of green materials or chicken manure can be quite nutrient rich, so care may be required not to overuse these in case of damage to plants.

Plastic in compost is the biggest impediment to sustainable use, so be vigilant about those little stickers on fruit and veg, and any other bits of rubbish or glass.