Composting is one of the oldest and most useful soil-building practices in farming. Long before synthetic fertilisers became widely available, farmers relied on compost, manure, crop residues, bedding, leaves, weeds and animal waste to return fertility to the land.
In regenerative agriculture, composting has come back into focus because it does far more than simply “add nutrients.”
Good compost can feed soil life, improve soil structure, increase organic matter, support water retention, recycle farm waste, reduce input costs and help create healthier, more resilient crops and pasture.
At its simplest, composting is the controlled breakdown of organic materials into a stable, earthy, soil-like material. But on a farm, composting can be much more than a waste management job. It can become part of the farm’s fertility cycle.
Instead of nutrients leaving the system, composting helps bring them back to the soil.
Whether you manage a livestock farm, market garden, orchard, mixed farm, smallholding or community growing project, composting can play a valuable role in improving soil health.
Farm composting is the process of turning organic farm materials into compost that can be returned to the land.
These materials may include:
Through composting, bacteria, fungi, worms and other organisms break these materials down into a more stable form. When managed well, the result is dark, crumbly compost with an earthy smell.
Good compost should not smell rotten, sour or strongly of ammonia. It should look and feel like something the soil wants to eat.
Because that is basically what it is.
Regenerative agriculture focuses on improving the health of the whole farm ecosystem. Soil fertility is not seen as something that only comes from a bag. It is something that can be grown, cycled and rebuilt through good management.
Composting supports several regenerative aims:
A farm that composts well is turning “waste” into fertility. That is a beautiful thing.
Manure, bedding, crop residues and plant waste are not problems to get rid of. They are resources waiting to be transformed.
Composting offers many practical benefits for farms and growing systems.
Organic matter is central to healthy soil. It helps soil hold water, store nutrients, support microbes and form stable structure.
Many soils have lost organic matter through repeated cultivation, bare ground, erosion, overgrazing or low residue return. Compost can help rebuild it.
Compost adds stable organic material to the soil, where it can support long-term fertility and biological activity.
In sandy soils, compost can help improve water and nutrient retention. In clay soils, it can help improve structure and workability. In tired soils, it can help restart biological processes.
Compost is not a magic spell, but it is close enough to make soil people very excitable.
Healthy soil is alive with bacteria, fungi, protozoa, nematodes, earthworms, insects and many other organisms.
Compost provides food and habitat for this underground life.
When compost is added to soil, it can help stimulate biological activity. Microbes break down organic materials, cycle nutrients and support plant growth.
Good compost may also introduce beneficial microorganisms, although the exact biology will depend on the composting method, materials and maturity.
Soil organisms are the engine of natural fertility. Compost helps fuel that engine.
Soil structure affects how air, water and roots move through the ground.
Poor structure can cause compaction, waterlogging, runoff, erosion and weak plant growth. Compost helps improve structure by supporting the formation of soil aggregates.
These aggregates are small crumbs of soil held together by organic matter, fungal threads, microbial glues and root activity.
Well-structured soil is easier for roots to explore. It also allows water to soak in and drain more effectively.
Over time, compost can help soil become more crumbly, porous and resilient.
One of the most valuable benefits of compost is improved water retention.
Organic matter acts a bit like a sponge. It helps soil hold moisture during dry periods while also improving infiltration during heavy rain.
This is increasingly important as farms face more unpredictable weather, including droughts, heatwaves and intense rainfall.
Compost can help:
For market gardens and horticulture, compost-rich soils can make a huge difference to crop performance in dry weather.
For pasture and arable systems, compost can contribute to longer-term improvements in soil water function.
Farms often produce large amounts of organic material.
Without good management, this material can become a waste issue. With composting, it becomes part of the nutrient cycle.
Composting can recycle nutrients from:
Rather than losing nutrients through runoff, leaching or poor storage, composting helps stabilise them and return them to the land.
This can reduce dependence on imported fertilisers and improve the farm’s circularity.
In regenerative farming, this matters. The aim is to keep nutrients cycling within the system wherever possible.
Compost may reduce the need for some bought-in fertilisers, soil conditioners or growing media.
The financial benefit depends on the farm system, the materials available, labour, machinery and compost quality.
Making compost is not free. It takes time, space, equipment and management. But if a farm already has manure, bedding or crop residues, composting can turn these materials into a valuable resource.
For market gardens, compost may be one of the most important fertility inputs. For livestock farms, composting manure and bedding can improve nutrient use and spreading quality. For mixed farms, compost can help connect livestock and cropping enterprises.
Compost is not just a cost-saving tool. It is a resilience tool.
Composting is driven by microorganisms. These tiny organisms break down organic materials when the conditions are right.
To make good compost, you need a balance of:
If these are balanced, composting works well. If they are out of balance, the heap may become smelly, slimy, dry, slow or anaerobic.
Compost needs both carbon and nitrogen.
Carbon-rich materials are often brown, dry or woody. They provide energy and structure.
Examples include:
Nitrogen-rich materials are often green, fresh or manure-based. They help fuel microbial activity.
Examples include:
A compost heap with too much carbon may break down very slowly. A heap with too much nitrogen may smell of ammonia or become slimy.
The art is in the balance.
A commonly suggested target is around 25–30 parts carbon to 1 part nitrogen, but most farmers manage this more practically by mixing “browns” and “greens” until the heap behaves well.
Compost needs moisture, but not too much.
A good compost heap should feel like a wrung-out sponge. Moist, but not dripping.
If it is too dry, microbial activity slows down. If it is too wet, oxygen is pushed out and the heap can become anaerobic.
Signs of poor moisture balance:
If a heap is dry, add water or wetter materials. If it is too wet, add dry carbon materials such as straw, woodchip or dry leaves.
Composting needs air.
Aerobic composting means decomposition happens with oxygen. This produces better-smelling, more stable compost.
If there is not enough oxygen, the heap becomes anaerobic. Anaerobic heaps often smell rotten, sour or sulphurous.
Oxygen can be maintained by:
A compost heap should not be a soggy lump. It should have enough structure for air to move through.
In hot composting, microbial activity raises the temperature of the heap.
Heat helps speed decomposition and can kill many weed seeds and pathogens if managed correctly.
A farm compost heap may go through different temperature stages:
Temperature can be monitored with a compost thermometer.
Very hot heaps may need turning to avoid overheating. Cool heaps may need more nitrogen, moisture, size or structure.
There is no single best composting method. The right approach depends on your farm scale, materials, space, labour and goals.
Windrow composting is one of the most common methods on farms.
Organic materials are piled into long rows, called windrows. These are turned periodically to add oxygen, mix materials and manage temperature.
Windrow composting works well for:
Benefits include:
Challenges include:
Windrows should be located away from watercourses and managed to prevent leachate or nutrient runoff.
Static pile composting involves building a heap and leaving it mostly undisturbed.
This is simpler than windrow composting but usually slower unless airflow is carefully managed.
Static piles can work well for smaller farms, gardens and systems with bulky materials that allow air movement.
Benefits include:
Challenges include:
Static piles need good structure. Woodchip, straw or branches can help maintain airflow.
This is similar to windrow composting but on a smaller scale.
Materials are piled into heaps and turned with a loader, tractor bucket, fork or compost turner.
This method is suitable for:
It is flexible and relatively easy to manage.
The key is to turn often enough to provide oxygen but not so often that the heap loses too much heat or moisture.
Vermicomposting uses worms to break down organic material.
The result is worm compost or vermicast, which can be very biologically active and useful in horticulture.
Vermicomposting works best with pre-composted or softer organic materials rather than fresh hot manure, which can be too strong or hot for worms.
Benefits include:
Challenges include:
Vermicompost is often used as a high-value amendment rather than spread broadly across large acreages.
The Johnson-Su bioreactor is a composting system designed to produce fungal-rich compost with minimal turning.
It uses a static, aerated design and is often discussed in regenerative agriculture circles.
The method aims to create mature, microbially diverse compost that can be used in small amounts as an inoculant or soil amendment.
Benefits may include:
Challenges include:
For farms interested in soil biology, it may be worth trialling on a small scale.
Many livestock farms have access to manure mixed with bedding. This can be excellent compost material.
Common bedding materials include:
Manure provides nitrogen and moisture. Bedding provides carbon and structure.
Composting bedding before spreading can improve handling, reduce smell, stabilise nutrients and create a more soil-friendly product.
The carbon-to-nitrogen balance will depend on the bedding. Sawdust and wood shavings are high in carbon and may need enough manure or nitrogen-rich material to break down well.
Useful compost ingredients include:
Some materials need caution.
Avoid or carefully manage:
Persistent herbicides in hay, straw, grass clippings or manure can damage crops even after composting. This is especially important for market gardeners.
When in doubt, test material before spreading it widely.
Here is a simple process for making compost on a farm.
Choose a composting area that is practical and environmentally safe.
A good site should be:
You may need to check local rules, especially for larger-scale composting or imported materials.
Collect a balance of carbon-rich and nitrogen-rich materials.
For example:
Chop or shred bulky materials where possible. Smaller pieces compost faster, though some larger pieces help maintain airflow.
Build the heap large enough to heat up but not so large that it compacts or becomes difficult to manage.
A useful heap should have:
Layering can work, but mixing is often better for even composting.
Avoid creating a dense, wet pile of nitrogen-rich material. That is how you summon the stink goblin. Nobody wants the stink goblin.
Check the heap regularly.
Use:
A healthy hot compost heap should warm up within a few days if conditions are right.
If it smells bad, something is wrong. Usually it is too wet, too compacted or lacking carbon.
If nothing is happening, it may be too dry, too small, too woody or lacking nitrogen.
Turning adds oxygen and mixes materials.
Turn the heap when:
Do not turn constantly for no reason. Too much turning can dry the heap and lose heat.
The right turning schedule depends on the method and materials.
Compost needs time to mature after the hot phase.
Curing allows remaining materials to stabilise and biological activity to balance.
Immature compost can tie up nitrogen or harm seedlings. Mature compost is usually darker, crumbly, earthy-smelling and no longer recognisable as the original materials.
Curing may take weeks or months depending on the system.
Compost can be spread on:
Application rates depend on compost quality, soil test results, crop needs and nutrient content.
Compost is not just “more is better.” Too much can overload nutrients, especially phosphorus or potassium.
Use compost as part of a soil fertility plan.
Finished compost should usually be:
Simple maturity checks include:
A seed germination test is useful for horticulture. Sow fast-germinating seeds such as cress in compost and compare with a control. Poor germination may suggest the compost is immature or contaminated.
In arable systems, compost can help build organic matter, improve structure and support nutrient cycling.
It may be used:
Large-scale compost use requires planning around spreading equipment, nutrient management and cost.
Livestock farms often have manure and bedding that can be composted before spreading.
Composting can improve manure handling, reduce odour and create a more even product.
Composted manure can be applied to pasture, herbal leys or forage crops, helping return nutrients to the land.
Compost is often central to market gardening, especially in no-dig systems.
It can be used to:
Market gardens may use larger amounts of compost per area than broadacre farms, so compost quality is especially important.
Contamination from herbicides, plastics or immature material can cause serious crop problems.
Compost can support tree establishment and orchard soil health.
It may be applied:
Avoid piling compost directly against tree trunks, as this can encourage rot.
Compost works especially well alongside mulch, living ground cover and fungal-friendly management.
Composting problems and sollutions
Likely causes:
Fix it by adding dry carbon material and turning the heap.
Likely causes:
Fix it by adding water, nitrogen-rich material, or increasing heap size.
Likely causes:
Fix it by adding straw, woodchip or dry leaves and improving drainage.
Likely causes:
Fix it by adding water or wetter green materials.
Likely causes:
Fix it by better temperature management and avoiding mature seed heads.
Possible causes:
Fix it by testing, curing longer and checking input materials.
Farm composting may be subject to rules depending on where you are, what materials you compost, whether waste is imported, the scale of the operation and how compost is used.
Things to check include:
For small-scale composting of your own farm materials, the process is usually simpler. For larger operations or imported waste, rules can be more involved.
Always check current local guidance before composting at scale or bringing materials onto the farm.
Compost works best when used alongside other soil-building practices.
For true soil regeneration, combine composting with:
Compost is powerful, but it is not the whole system.
If compost is added to bare, compacted, heavily disturbed soil, some benefits may be lost. If compost is added to covered, living, biologically active soil, it becomes part of a much healthier cycle.
The aim is to create soil that can increasingly generate its own fertility.
Compost and fertiliser are different tools.
Synthetic fertiliser usually provides concentrated plant nutrients. Compost provides nutrients too, but also adds organic matter, biology and structure-building material.
Compost is generally slower-release and more system-building. Fertiliser is usually more targeted and immediate.
In regenerative farming, the long-term goal is often to reduce dependence on synthetic fertilisers by improving soil function. Compost can be an important part of that transition.
But compost should still be used intelligently. It is possible to overapply compost or create nutrient imbalances.
A healthy fertility strategy considers soil tests, crop needs, organic matter, biology, rotations and nutrient flows.
Composting for farms is about much more than tidying up waste.
It is about turning organic materials into fertility. It is about closing nutrient loops, feeding soil life, building organic matter and supporting healthier crops, pasture and ecosystems.
A good composting system can transform manure, bedding, crop residues, leaves, weeds and plant waste into one of the farm’s most valuable resources.
The basic principles are simple:
Compost is not a silver bullet. It works best as part of a wider regenerative approach that includes soil cover, living roots, plant diversity, reduced disturbance and careful grazing.
But as part of that system, compost is a quiet powerhouse.
It takes what is finished and turns it into a beginning.
