Starting a Compost Heap: Turning Garden Waste into the Best Soil
Choose the location, layer correctly, turn the heap – how nutrient-rich humus is made in your garden
Disclaimer
This guide has been prepared with great care. Nevertheless, we accept no warranty for the accuracy, completeness or currency of its contents. You follow this guide at your own risk – any liability for personal injury, property damage or financial loss arising in connection with its use is excluded. The contents do not replace professional advice for your individual situation. Always observe the manufacturer instructions of your tools and materials as well as applicable local regulations (e.g. building codes, neighbour law, utility line enquiries before digging). Work on electrical, gas or water lines and on load-bearing structures must only be carried out by qualified professionals.
Choose the location, layer correctly, turn the heap – how nutrient-rich humus is made in your garden
Composting is the simplest form of recycling: grass clippings, leaves and vegetable scraps that would otherwise end up in the organic waste bin become nutrient-rich humus in your own garden – the best fertiliser and soil improver there is. Little can go wrong as long as three basic rules are observed: the right location (semi-shaded, on open soil), a balanced mix of moist and dry materials, and turning the heap occasionally. Then the compost heap delivers mature compost after 9–12 months, ready to feed your beds, lawn and container plants.
Tools
- Digging fork or pitchfork
- Spade
- Secateurs or shredder for coarse material
- Wheelbarrow
- Throw-through sieve (approx. 15–20 mm mesh) for harvesting
Materials
- Compost bin: open slatted composter, wire composter or thermo composter – or simply an open heap
- Coarse material (branches, shrub cuttings) for the bottom layer
- Mixed compost material: grass clippings, leaves, vegetable scraps, coffee grounds, eggshells
- A little mature compost or garden soil as a starter if available
Step by Step
Choose the location
Ideal is a semi-shaded, wind-sheltered spot, for instance under a tree or beside a hedge: in full sun the compost dries out, in deep shade it stays too wet. The compost must stand on open garden soil – never on concrete or slabs – so earthworms and micro-organisms can migrate in and excess water can drain away. With the neighbours in mind, a little distance from the boundary and a spot away from the seating area have proven sensible.
Set up the bin and build the base layer
Loosen the ground on the footprint with the digging fork and place the composter on top. The bottom layer consists of 10–20 cm of coarsely chopped branches and shrub cuttings – this drainage layer keeps the heap aerated from below and prevents waterlogging. If you like, set up two bins side by side: one for filling, one for maturing.
Know what goes in – and what does not
Allowed: fruit and vegetable scraps, coffee grounds including the filter, eggshells, grass clippings (wilted and in thin layers), leaves, perennial cuttings, chopped shrub prunings and small amounts of unprinted cardboard. Not allowed: cooked food leftovers, meat, fish, dairy products and bread (they attract rats), diseased plants, seeding weeds and root weeds such as ground elder or couch grass, larger amounts of treated citrus peel, and generally glass, plastic, coal ash and treated timber.
Fill in layers and keep it well mixed
The rule of thumb: always alternate or mix moist, nitrogen-rich material (grass clippings, kitchen scraps) with dry, carbon-rich material (leaves, chopped branches, straw) – roughly in a ratio of 1:2 to 1:3. Never add grass clippings in layers thicker than 5–10 cm, or they rot into a stinking, slimy mat. Scatter in a shovel of mature compost or garden soil now and then – it inoculates the heap with the right micro-organisms.
Keep an eye on moisture
The compost should be as moist as a wrung-out sponge. The fist test: squeeze a handful of material – it should feel damp, but no water should drip out. Water occasionally in dry summers; cover an open heap with fleece or a layer of straw during prolonged rain.
Turn the heap after a few months
After about 3–6 months, turn the heap once completely: rebuild it next to the old spot (or into the second chamber) with the digging fork, mixing the outside to the inside and the inside to the outside. Turning brings oxygen into the heap and speeds up decomposition considerably. Moisten dry zones as you go and mix wet zones with dry material.
Check maturity and harvest the compost
After 9–12 months (often faster in a thermo composter) the compost is mature: dark brown, crumbly, with a pleasant smell of forest soil – the original materials are no longer recognisable. To harvest, throw the material through a coarse sieve; oversized pieces go back into the new heap. Spread mature compost at 2–3 l/m² on beds and lawn in spring and work it in shallowly.
Safety First
- Wear gloves when working on the compost and cover any wounds – soil and decomposing material can contain pathogens.
- Work back-friendly when turning the heap: small forkfuls, lift from the legs, take breaks.
- Wear safety glasses and gloves when shredding prunings and observe the rental company’s machine introduction.
- Do not compost cooked food leftovers, meat or dairy products – they attract rats and other unwanted guests.
Mistakes You Should Avoid
Compost on a sealed surface
On concrete or slabs, the contact with soil life is missing: earthworms and micro-organisms cannot migrate in, water pools at the base, and the heap putrefies instead of composting. Open garden soil is the basic requirement for any compost.
Thick layers of grass clippings
Fresh grass clippings in a thick layer stick together into an airtight, rotting mat – the most common reason for smelly compost heaps. Let clippings wilt first and add them only in thin layers, mixed with leaves or shredded material.
Never turning, never mixing
A heap that is only filled and never moved compacts, receives no oxygen and takes years instead of months. Turning it once after a few months and keeping a balanced mix of moist and dry material halves the composting time.
Common Questions
What can go on the compost heap?
Raw fruit and vegetable scraps, coffee grounds, eggshells, grass clippings in thin layers, leaves, perennial cuttings and chopped shrub prunings. Cooked food leftovers, meat, fish and dairy products, diseased plants, seeding and root weeds, and anything non-organic do not belong in it.
How long does compost take to be ready?
In a well-mixed open composter that is turned once, mature compost takes about 9–12 months. Thermo composters often manage it in 6 months thanks to higher temperatures. Coarse compost that is never turned, on the other hand, can take 2 years.
Why does my compost smell bad?
A putrid smell indicates a lack of oxygen – usually from too much wet material such as thick grass clippings, or from waterlogging at the base. The remedy: turn the heap, mix in dry structural material (leaves, chopped branches, straw) and alternate moist and dry when filling in future. Healthy compost smells of forest soil.
Which location is ideal for a compost heap?
Semi-shaded, sheltered from wind and always on open garden soil – for instance under a deciduous tree. In full sun the heap constantly dries out; in deep shade it stays too cold and wet. A few metres of distance from the seating area and the neighbour’s boundary spare you discussions.
How do I know when the compost is mature?
Mature compost is dark brown, finely crumbly and smells pleasantly of forest soil – the original waste is no longer recognisable. A simple check is the cress test: sow cress seeds in a tray of the compost; if they germinate quickly and grow green leaves, the compost is mature and safe for plants.
When is a professional worth it?
If more green waste accrues than one compost heap can handle – after a major hedge cut or tree felling, for example – we take care of shredding and proper removal. And if you want to improve your soil on a larger scale, we deliver compost and topsoil in any quantity and work it in by machine – for instance as the basis for a new lawn or new planting areas. From a single load to a complete garden redesign with beds, paths and irrigation, we are your point of contact.
