‘Black gold’—that’s what serious gardeners call compost. Nourish your plants and vegetables some ‘black gold’, and they’ll perk right up. In fact, research has shown that compost improves a tomato plant’s yield, nutrition, and taste.
Yet composting helps more than your garden. It also helps our environment. Read on and find out how to make compost
Food scraps in landfill release greenhouse gases
Food scraps never look like much waste, yet account for 30% of the rubbish in Australia’s household bins. Food scraps in landfill rot and release greenhouse gases. In Australia, around 3% of our greenhouse gas emissions come from organic matter rotting anaerobically in landfills. That’s about as much as our aviation industry.
However, when you compost, food scraps decompose and are recycled back into the soil—without releasing any greenhouse gases.
Our team at All Green Nursery & Garden are ready to help you make your garden as eco-friendly as possible. You can also find a wide variety of native and exotic plants, beautiful pots, and more garden supplies.
Step 1. Setting up your compost
The first step in how to make compost: you need to decide how and where to create your compost.
Option 1. Compost heap in your backyard
Clear a patch of dirt in your backyard for a compost heap. Make sure it’s a well-drained spot that receives sunlight throughout the day. While this option has no setup costs, it is the least effective composting process.
Option 2. Stationary compost bin
This is the most popular composting setup. Compost bins break down organic matter faster because they retain moisture and heat, which is why most compost bins are black. Choose a size that matches the amount of food scraps your household produces. Placing the bin in direct sunlight will help your compost decompose faster.
Option 3. Rotating compost bin
Rotating bins help aerate and mix the compost together (they come with a handle that lets you easily spin the bin). Compost decomposes fastest in a rotating bin, although they might be more expensive to set up.
Step 2. Adding the compost ingredients
The compost process
Every compost needs nitrogen and carbon. Nitrogen comes from green matter like kitchen scraps and lawn cuttings, while carbon comes from the ‘brown’ ingredients like leaves and straw. So every compost needs ‘green’ and ‘brown’ organic matter.
Balancing the ingredients with layering
If you have too much green matter, the compost can become wet and smelly (because the organic material begins rotting instead of composting). Conversely, if you have too much brown matter the compost can be too dry, lack the necessary nitrogen, and take years to decompose. So how do you balance the ingredients?
A few rules of thumb will help you get the right mix:
- Start by adding a bottom layer of thicker brown material like twigs and mulch (for drainage). Then add a layer of green material, followed by a brown layer. The initial mix should be around one-part green to three-parts brown.
- If your compost looks too wet or is smelly, add more brown ingredients. If it looks too dry, add more green ingredients and water.
- Consult the following lists of materials to add and avoid.
Green materials to add
- Vegetable scraps
- Fruit scraps
- Coffee grounds
- Plant clippings
- Grass cuttings
- Tea leaves and tea bags
- Soft stems
Green materials to avoid
- Anything containing meat, bones, oil, fat, or grease
- Dog or cat faeces
- Dairy products
- Bread or cake (may attract mice)
Brown materials to add
- Dry leaves
- Finely chopped wood and bark chips
- Shredded newspaper
- Sawdust from untreated wood
- Dead flowers
- Old potting mix
- Old newspapers, cardboard, and boxes (wet)
Brown materials to avoid
- Diseased plant materials
- Sawdust or chips from pressure-treated wood
- Weeds that go to seed
- Large branches
Step 3. Maintaining the compost
Your compost should be watered frequently so it has the consistency of a damp sponge. But be careful not to add too much water. When a compost becomes waterlogged, the microorganisms die, and it starts rotting. So keep the compost moist, but not wet.
Maintaining the right temperature
The easiest way to check the temperature is the hand-test. How does the hand-test work? It’s simple—stick your hand into the pile. If it feels warm, it’s at the right temperature. If it’s cool, try moving the compost into the sun, using a black container (to absorb heat), or adding more brown ingredients (the carbon creates energy/heat).
Best decomposition heat is between 40 and 60°C. At the temperature higher then 65°C, most of the beneficial microorganisms will die.
Aerate the pile
Provide oxygen to the compost by turning it over with a garden fork once a week. Furthermore, mixing the brown and green material together speeds up the compost process—so mix thoroughly.
Step 4. Feeding the garden
Compost can take anywhere from six weeks to one year to decompose (if you follow the above recommendations it will be six to twelve weeks).
How do you know when it’s ready? Compost is ready when it looks like dry, brown, crumbly soil. Or as gardeners say, when it looks like ‘chocolate cake’. So when it’s ready, you can feed the ‘chocolate cake’ to your vegetables, herbs, or plants. Simply grab a shovel, add it to your garden, and mix the compost into the topsoil.
Composting our food scraps gives us a healthy garden. And more critically, it helps us care for Australia’s environment. And that is how to make compost.