Turning food waste into a useful resource is possible, and often easier than you might think. Composting does not require a garden, special skills or complex equipment, just a few basic principles to understand and a few easy mistakes to avoid.
In this guide, you will discover how composting really works, how to choose the right method for your situation, and how to make effective compost without odours or pests. Whether you live in a house, an apartment or a business, you will find practical tips to help you get started.
What is compost?
Compost is the result of a natural process of organic matter decomposition in the presence of oxygen, moisture and a variety of microorganisms. It produces a stable, humus-rich material that improves soil structure and fertility.
In other words, what we throw away (peelings, coffee grounds, vegetable scraps, etc.) can be turned into useful organic fertiliser, provided a few simple rules are followed.
This process is neither dirty, dangerous nor complex. It is based on a biological balance between inputs, air and water.
What are the different types of composting?
There are several methods of composting. They all have the same objective but are adapted to different contexts in terms of space, volume and frequency of use.
Aerobic composting (i.e. ‘in the presence of oxygen’, the most common type)
- Requires regular mixing
- Enables effective, odourless degradation with good monitoring
This is the composting method used in traditional domestic composters, shared composters, and in businesses.
It can take different forms, depending on the material used:
- Static bin composting (standard in gardens)
- Rotating composter, which facilitates aeration through regular mixing. Handcrafted/DIY in private homes, this system is also used by Easy To Compost due to its simplicity and effectiveness in models for businesses and local authorities.
- Electromechanical composter (plugged into the mains), which automates certain functions (aeration, temperature, mixing): this type of equipment is suitable for facilities that process larger volumes, with higher budgets and maintenance teams.
Vermicomposting
- Use earthworms, which are naturally occurring worms found in soil, some species of which are known for their usefulness in composting (Eisenia fetida worms, in particular).
- Suitable for small volumes, indoors or on a balcony.
- Very little odour, fast composting, but sensitive to temperature variations or errors in input.
- The compost produced is highly concentrated, with a rich ‘juice’ (called compost tea) that must be diluted before use as a fertiliser.
Ideal for apartments, small offices or educational establishments.
Bokashi (fermentation anaérobie)
- An oxygen-free process based on inoculation with microorganisms (EM).
- The bokashi system is based on the fermentation of waste in a sealed bucket using specific microorganisms. This process is anaerobic (without oxygen): it does not produce compost as such, but a pre-digested material, which must then be buried or added to traditional compost to complete its maturation.
- It can be useful for small spaces or as a first stage of treatment, but does not work on its own in the long term.
Compact solution, effective indoors, but requires an additional maturation step.
Composting in piles or pits
- Rustic method: piles on the ground or in a hollow
- Requires space, not very suitable for urban environments
- Slow but not very restrictive
Suitable for gardens, farms or rural areas with low foot traffic.
The choice of composter depends on several criteria: available space, the amount of organic waste produced, the type of building (individual or collective), the environment (urban or rural) and the intended use (domestic or professional).
| Type of composter | What is it for? | Advantages | Limitations |
| Garden composter | Detached house with outdoor space | Robust, large capacity | Requires some maintenance |
| Rotary composter | Regular domestic use | Brassage facile, compost plus rapide | Limited capacity |
| Electromechanical composter | Canteen, catering, company | Automated, fast, hassle-free | High cost, need for power supply |
| Compost bin | Apartment, office, interior | Odourless, compact | Sensitive to temperature and humidity |
| Bokashi | Indoor kitchen | Compact, fast, low maintenance | Result to be buried or composted afterwards |
| Shared compost bin | Co-ownership, neighbourhood | Sharing, social ties | Requires good coordination |
Some devices sold as ‘kitchen composters’ are actually dehydrators. They heat organic waste to high temperatures, dry it out and then grind it. The result is a dry, inert residue with no biological activity.
In addition to the machine’s high energy consumption, unlike mature compost, this residue:
does not enrich the soil with living organic matter, does not constitute a complete soil amendment, and often has to be buried or thrown away. These devices may be useful on an occasional basis (to reduce volume in kitchens), but they do not produce compost. They are therefore no substitute for home composting or serious bio-waste management.
Why make compost?
Composting addresses three specific issues:
Feeding the soil
Soils are degrading, eroding and losing their ability to retain water or support microbial life. Compost enables:
- restore stable organic matter,
- improve the structure of cultivated or urban land,
- actively participate in soil regeneration.
Avoid transporting (and burning) organic waste
Biowaste thrown away with household rubbish is collected by truck, sometimes transported dozens of kilometres away, incinerated or buried… even though it is wet (containing around 80% water on average!) and could be recycled locally. Composting allows waste to be treated where it is produced, without transport or heavy infrastructure, and avoids costly and inefficient treatment methods.
Better control of waste streams (and costs)
Since January 2024, sorting bio-waste at source has become mandatory for everyone. Composting therefore helps to reduce the volume of waste collected (and therefore the bill) and provides a tangible and easily understandable solution for users (particularly in businesses and local authorities).
Practical guide to composting: how does it work?
What should you put in a composter?
Compost works thanks to the activity of microorganisms and insects that transform waste into humus. To do this, they need two main types of elements: nitrogen-rich materials (fresh waste, known as ‘green’ waste) and carbon-rich materials (dry materials, known as ‘brown’ waste).
Why is it necessary to balance nitrogen and carbon?
It’s a question of energy and biological balance. Carbon is the main source of energy for microorganisms. Nitrogen is used for their growth and to produce their enzymes. If you add too much nitrogen-rich waste (peelings, coffee grounds, fresh grass), you create excess moisture, acidity and unpleasant odours. If you add too much dry material, the decomposition process stops.
The optimal balance is approximately two-thirds brown material to one-third green material by volume.
A few tips to keep in mind
- Crushed eggshells help regulate the acidity of compost, especially if you add a lot of fruit or citrus fruits.
- Coffee grounds, rich in nitrogen, are also a natural repellent against certain insects.
- Kitchen roll can be composted if it is not greasy or printed.
Why should certain types of waste be avoided?
Meat, fish, dairy products and fatty cooked dishes do not break down well in home composting. They attract pests (rats, flies) and cause anaerobic fermentation, which leads to odours and slows down the process.
Fats, on the other hand, coat other waste and prevent oxygen from circulating in the pile.
Finally, non-organic waste (plastics, mineral litter, treated wood) is simply… non-compostable.
How to choose the right location for your composter?
The location of the composter directly influences the success of the process. It must be accessible, stable, and suitable for the type of composter used.
Garden composter or static bin
Outdoors, choose an area:
- On the ground, to allow access to earthworms and insects
- Partially shaded, to limit excessive heat or humidity
- Sheltered from strong winds, which dry out the contents
- Easy to access even in winter
- Avoid concrete surfaces: the lack of contact with the ground slows down natural biological activity. And remember to set aside some space to store a little ‘dry brown matter’ within easy reach (dead leaves, shredded cardboard, etc.).
Rotating composter
This type of composter is closed and raised: it can be installed on any flat surface, including a terrace or slab. However, care must be taken to fill it gradually, maintaining a balance between nitrogen and carbon, as the absence of soil means that microbial activity is more limited at the outset.
Worm composter
It is a living system: worms are sensitive to temperature, humidity and light.
- Ideal temperature: between 15 and 25°C
- Below 10°C: activity slows down
- Above 30°C: worms may die or escape
Avoid window sills, poorly ventilated cupboards, damp cellars or balconies exposed to direct sunlight.
A worm composter is best placed in a discreet but temperate corner: kitchen, office, insulated garage, etc.
Bokashi
As this system is completely sealed, it can be installed in any kitchen, including professional kitchens. No contact with the floor or ventilation is required: fermentation is anaerobic. However, be sure to empty the fermentation juice regularly (every 2 to 3 days) to prevent maceration. A discreet, poorly located or poorly identified composter will not be used very often. On the other hand, a visible, well-sized composter accompanied by a small animation or display can generate real collective support.
How to maintain your compost: best practices
Contrary to popular belief, a composter is not a stand-alone ‘green bin’. It is a living ecosystem that requires a certain amount of regular maintenance to function properly. It’s not complicated, but a few simple steps can make all the difference.
Aerate the composter regularly
Compost needs oxygen to allow microbial life to develop. Without air, anaerobic bacteria take over: they generate unpleasant odours, slow down decomposition and promote fermentation.
→ Turning the compost (with a pitchfork or a manual aerator) once every two weeks is sufficient, or each time you add something if the volume is large.
→ In a rotating composter, turning is built in: simply turn it two or three times a week.
→ In a worm composter, there is no mixing: the worms take care of that. However, brown material must be added regularly to maintain the structure.
Check the moisture level in the composter
Compost should be as moist as a wrung-out sponge. If it is too dry, the microorganisms will stop working. If it is too wet, the waste will clump together and rot.
→ If it is too dry: add a little water in a fine spray, or some well-distributed moist waste.
→ If it is too wet: add brown material (cardboard, dry leaves), aerate, and leave the lid slightly open for a few days.
Add brown material every time you add green material to the composter
Every time you add food waste (moist, nitrogen-rich material), add a small handful of dry (brown) material to maintain the balance. This promotes aeration, prevents bad odours and limits the arrival of gnats.
In a business or canteen, keeping a small bucket of dry brown material next to the composter is a simple good practice that is easy to implement.
Observe the compost
Good compost has a slight smell of undergrowth. It is populated by small useful creatures (worms, woodlice, springtails, rose chafer beetles). Their presence is normal and even desirable. However, if pests appear (gnats, flies, rodents), this is usually a sign of an imbalance (too much green matter, lack of dry matter, addition of cooked food scraps).
How long does it take to make compost?
The duration depends on several factors: the type of composter, the climate, the regularity of inputs, the size of the waste and the quality of maintenance.
How can you tell when compost is ready?
- It smells like forest soil, with no ammonia or fermentation odours.
- Its texture is uniform, dark and slightly lumpy.
- No recognisable waste is visible (except for the hardest items, such as pits or eggshells).
- It is crumbly and does not stick to your fingers.
Comment fabriquer son composteur soi-même ?
It is entirely possible to build a functional composter with limited resources.
Build a garden composter (using pallets)
- 3 to 4 wooden pallets for the walls
- A tarpaulin or cover to protect from rain
- A base without a bottom (directly on the ground)
- A front opening for turning
Simple, robust, and ideal for medium to large gardens.
Making a homemade worm composter
- 3 stacked food-grade containers
- Holes in the upper containers to allow worms to move around
- A bottom container to collect the juice (“compost tea”)
- A ventilated lid
Frequently asked questions
“My compost smells bad”
Probably too much wet waste (fruit, cooked vegetables) and not enough brown material. Aerate, add cardboard, turn the pile over.
“There are gnats everywhere”
Fruit is too visible or on the surface, the bin is not closed properly, excess moisture. Cover each addition with dry material.
“My worm composter is infested with white worms”
This isn’t necessarily a problem: they are often rose chafer beetles, which are useful for compost. However, if there is a strong smell and black larvae, be careful: you need to rebalance the bin.
“My compost isn’t breaking down”
Lack of moisture or nitrogen. Compost must remain alive: stir, moisten, add a little fresh waste.
‘It’s too complicated at my house’
No, you just need to choose the right solution. On a balcony, a worm composter is easier than you might think. In businesses, there are solutions for all volumes, including break rooms.