One year in the life of our farm's compost pile
Every handful of finished compost that goes onto our lettuce beds represents roughly a year of patient biological work. Our family operation in Chuckey, Tennessee, sits in a temperate corner of the southern Appalachians, but the rhythms of decomposition we observe mirror those that play out in backyards and community gardens from Hobart to Cairns. Watching a pile of kitchen scraps, manure, and leaves transform into dark, crumbly humus is one of the most satisfying loops in food production.
Australians produce around 7.6 million tonnes of food waste each year, according to federal data, and the National Food Waste Strategy aims to halve that figure by 2030. Backyard composting is one of the simplest ways households can contribute to that goal, and commercial operations like ours show how the same principles scale up. From council caddies in Melbourne and Brisbane to industrial windrows behind Adelaide restaurants, the science is identical. Carbon meets nitrogen, microbes multiply, heat builds, and the original material disappears into something richer.
Our own compost journey begins with grass-fed cattle manure, pasture-raised pig bedding, and the trimmings that never make it from the hydroponic greenhouse to the wash line. We add leaves in autumn, wood shavings from the goat barn, and whatever fruit pulp comes back from a jam-making neighbour. Over twelve months that mixture passes through distinct phases, each with its own colour, smell, temperature, and microbial cast.
Building the foundation: what goes into the pile
The recipe for a hot, fast-working compost pile is roughly two parts browns to one part greens by volume, with a carbon-to-nitrogen ratio between 25:1 and 30:1. Browns are dry and fibrous: autumn leaves, straw, sawdust, shredded cardboard. Greens are moist and rich in protein: food scraps, fresh manure, coffee grounds, garden prunings. On our farm the browns come from the goat barn, the woodlot, and bagged leaves collected from neighbours, while the greens arrive daily as lettuce trimmings, herb stems, and manure from the cattle, pigs, and alpacas.
| Material type | Common examples we use | Approximate C:N ratio | Breakdown time in our pile |
|---|---|---|---|
| Browns (carbon) | Fallen leaves, straw, wood shavings, shredded cardboard | 60:1 to 500:1 | 6 to 12 months |
| Greens (nitrogen) | Manure, food scraps, fresh grass, coffee grounds | 15:1 to 30:1 | 2 to 8 weeks |
| Mixed bedding | Pig and goat bedding with manure | 40:1 to 80:1 | 3 to 6 months |
| Avoid | Meat, dairy, oils, glossy paper, citrus in bulk | High variability | Slows or stalls pile |
The Australian Standard AS 4736 governs industrial compostable packaging, and we accept those materials from a Brisbane meal-kit service that drops off its returned trays each Friday. For home composters in Sydney or Perth, anything carrying the seedling logo breaks down alongside vegetable peelings, though chop large pieces so microbes can reach the centre. We avoid meat, bones, dairy, and large amounts of citrus, partly because they attract vermin and partly because oils and acids can throw the pile's chemistry off balance.
Moisture is the next ingredient we manage. A working pile should feel like a wrung-out sponge, damp but not dripping. During dry late summers we water the windrow from a tank, much like a gardener in Adelaide or the Mallee tending a bed through a heatwave. Too little moisture stalls microbial activity; too much and the pile goes anaerobic, producing sour smells rather than the sweet, earthy scent of healthy compost.
The thermophilic surge of summer
Once the pile reaches at least one cubic metre, thermophilic bacteria take over. Internal temperatures climb to between 55 and 70 degrees Celsius within days, hot enough to kill weed seeds and most pathogens. We monitor with a long-stem thermometer, and the first time the needle crosses 60 we know the biological engine is running. Australian summers can be punishing on the surface of a pile, so we cover the top with a breathable jute sack to keep moisture in and heavy rain off, similar to how a grower in Darwin might shade a seedbed.
Oxygen becomes the limiting factor as the centre compacts under its own weight. We turn the windrow every seven to ten days during this phase using a tractor-mounted bucket, which reintroduces air and shifts uncomposted material from the outside into the hot middle. After each turn the temperature dips briefly, then climbs again as fresh microbes colonise the new layers. Without turning, the pile would settle into a matted, smelly lump within weeks.
This summer phase typically lasts six to ten weeks, depending on weather and inputs. Once temperatures fall and stay below 40 degrees, the thermophilic crowd steps back and mesophilic organisms, including fungi and springtails, take over the slower work of decomposition. It is also the riskiest time for smells, which is why neighbours know to expect a faint, yeasty aroma rather than anything unpleasant.
Autumn inputs and the scent of forest floor
Autumn in the Appalachians looks a lot like autumn in the Yarra Valley or the Southern Highlands: leaves fall, gardens wind down, and carbon-rich material arrives in sudden abundance. We dedicate October to stockpiling leaves, often accepting trailer-loads from local schools and landscaping crews who would otherwise send them to landfill. These leaves form the bulk of next spring's brown layer and make up roughly a third of the pile's total volume.
Adding all those leaves at once can cool a pile rapidly, so we layer them with fresh manure and food scraps in alternating 15-centimetre bands, the same lasagna method taught in workshops from Fremantle to Fitzroy. The leaves also introduce a diverse fungal community, and within a few weeks we see white threads of mycelium threading through the dark material. Pulling back the top layer reveals a colour gradient from pale tan to deep chocolate brown.
Earthworms are latecomers to the autumn pile, migrating up from the soil beneath once temperatures moderate. Their castings are among the most valuable soil amendments we produce, packed with plant-available nutrients and beneficial bacteria. We do not add worms deliberately; instead we create conditions they prefer. If worms are thriving, the pile is biologically mature and close to finished.
Winter rest and slow refinement
Winter slows everything down. The pile's core temperature hovers around 20 to 30 degrees, and visible change happens on a weekly rather than daily scale. This is the maturation phase, where complex molecules like lignin and cellulose finish breaking down into stable humic compounds. We mostly leave the pile alone, only turning once in mid-January to redistribute any pockets of unfinished material.
For Australian readers managing compost in a cooler climate, winter is a good time to plan. Hobart and Canberra growers face similar low microbial activity, while those in tropical north Queensland must instead reckon with wet-season leaching. We use the quiet months to screen finished compost from the bottom of last year's pile, sieve it through a 10-millimetre mesh, and bag it for spring sales to restaurants and home gardeners alike.
By late February the screened material is ready, dark and crumbly, smelling of rain-soaked forest floor. We spread a thin layer across our hydroponic lettuce channels to refresh the substrate and donate several cubic metres to a community garden in nearby Greeneville. Nothing leaves the farm that does not eventually find its way back into the soil.
Putting the cycle to work
The compost that started as vegetable scraps and bedding becomes the foundation for the next generation of food. We blend it into our potting mix for the hydroponic troughs, side-dress our outdoor herb beds, and send bags home with anyone who visits the farm. For an Australian chef sourcing from local growers, knowing that compost was made from manure and trimmings produced on the same property closes a loop that industrial supply chains rarely manage.
Composting also helps farms and households cut methane emissions linked to food waste rotting in landfill. The federal Department of Climate Change, Energy, the Environment and Water highlights home and commercial composting as a practical action under the National Food Waste Strategy. Whether you live in a Brisbane apartment with a bokashi bin or on a rural block outside Ballarat with room for three bays, the same seasonal rhythm applies: build, heat, turn, rest, harvest.
Visitors to WhyNot Farm are welcome to walk past the compost bays during a scheduled tour, lift the lid, and feel the warmth rising from a pile that is working through another year. Reach out to schedule a visit, sample the lettuce, and watch the compost steam on a cold morning. Fresh greens, wholesale produce, and bags of finished compost are available at the farm gate, with delivery options across East Tennessee and beyond.