How Compost Works
While you can allow compost to happen, you can also help speed things along if you understand the process.
Compost just happens – it’s a natural phenomenon. If you pile leaves and twigs in a corner of your garden, eventually you’ll discover they have turned into a dark, fluffy, crumbly material: compost. While you can allow compost to happen, you can also help speed things along if you understand the process.
The workers that break down organic matter include microorganisms, fungi, and soil fauna (earthworms, millipedes, ants, etc.). You’ll create compost most efficiently when you design an environment that provides ideal conditions for these organisms.
Normally, decomposition takes a few months to several years. But if you create optimum conditions for the decomposers, you’ll get compost more quickly, maybe in as little as 14 days.
Start With the Right Ingredients
To produce compost, decomposers need four things: carbon, nitrogen, water and oxygen. Offer these ingredients in a balanced way, and you’ll get a quick turnaround from raw materials to finished compost.
Carbon. Materials rich in carbon (called “browns”) equate to energy food for decomposers. High-carbon materials are typically brown or tan, tough, and dry. Examples include corncobs, cornstalks, dry leaves, straw and shredded newspaper.
Nitrogen. High-nitrogen materials (called “greens”) provide protein for decomposers. Many nitrogen-rich items are green and moist, such as spent annuals, grass clippings and garden prunings. Kitchen scraps fall into this category, including non-green things like coffee grounds and eggshells. Although manures or meals (blood meal, kelp meal, etc.) aren’t green or moist, they’re also excellent sources of nitrogen.
Water. Like other living things, decomposers need moisture to survive. How much water is enough? The rule of thumb is to keep your compost pile as moist as a well-wrung sponge. You can water a compost pile if it dries out. Covering a pile with a tarpaulin or using an enclosed container can help regulate moisture.
Oxygen. Your army of decomposing organisms also needs oxygen to function best. As materials start to decompose in your pile, air pockets disappear. It’s vital to incorporate some method to introduce oxygen into your pile. Turning the pile accomplishes this, as do air vents on manufactured compost bins. For homemade compost systems, consider building the pile off the ground – on a pallet or layer of branches. You can also insert one or two pieces of 10cm perforated plastic pipe into the centre of the pile; shaking the pipe vigorously every other week increases airflow into the compost.
When you have the right ingredients present in the right proportions, decomposition occurs speedily. The decomposition process generates heat, which is vital for destroying weed seeds, plant pathogens, and disease organisms. Turning the pile helps ensure that adequate heat is maintained to produce problem-free compost.
Follow a recipe – or not!
You want to use roughly equal amounts of brown (carbon-rich) and green (nitrogen-rich) materials in a compost pile to achieve the fastest composting. Compost piles with too much brown and not enough green take years to decompose. Too much green and not enough brown produces a smelly, wet pile.
Try this approach:
- Build layers that are about 20cm thick, building up to 1m in total height.
- Try sprinkling 1 tablespoon of Natria Compost Activator over each layer.
- Water every other layer.
- Once the compost bin is full, leave for about 6 weeks, until the mixture is brown and has a crumbly texture.
- Either spread the compost over the garden as a mulch or soil improver, or mix with soil when preparing beds for planting.