How Can You Make Successful Compost?

Compost is the result of the natural breakdown of organic matter, such as fruit and vegetable peelings, fallen leaves, or grass clippings. Through the action of numerous living organisms, including bacteria, fungi, earthworms and microorganisms, this waste gradually decomposes to form a dark, crumbly and nutrient-rich material: compost.

This process mimics what happens naturally in ecosystems. In the presence of air and moisture, so-called green materials, which are rich in nitrogen, and brown materials, which are richer in carbon, are gradually broken down by soil fauna and microorganisms. After several months, the result is a natural soil improver that is highly valued in the garden for nourishing the soil and helping to maintain its fertility.

Making compost at home allows you to transform some of your everyday waste into a useful resource for the garden. Simple to set up, this practice supports a way of gardening that is more mindful of the soil, biodiversity and the major natural cycles.

To Make the Most of Your Organic Waste

Composting your organic waste gives it a new lease of life rather than simply throwing it away. Peelings, fallen leaves, coffee grounds and small bits of plant waste gradually transform into a rich, useful material to nourish the soil.

To Improve Soil Quality

Over the course of several months, compost produces a humus-rich material that helps improve soil structure and maintain its fertility. It also promotes water retention and can be used in the vegetable patch, at the base of fruit trees or in flowerbeds.

To Adopt the Principles of Agroecology

Making your own compost means reconnecting with the great cycles of life. Today’s plant waste becomes the material that will nourish tomorrow’s soil. This approach, at the heart of agroecology, encourages us to work in harmony with natural balances and to preserve soil life.

Adding compost to the garden nourishes the soil, encourages microbial life and gradually improves its structure. It is one of the foundations of living soil: soil that is looser, more fertile, better able to retain water and provides better growing conditions for plants.

Compost also helps to reduce the need for synthetic fertilisers and other chemical inputs, which can weaken soil life when used excessively. In organic gardening, the benefits of compost are numerous, including:

• Improved Soil Fertility: Rich in organic matter, compost nourishes the soil sustainably and supports the growth of plants

• More Active Soil Life: By adding organic matter, it encourages the activity of microorganisms, earthworms and all the small creatures that are beneficial to the garden

• Better Plant Growth: A living, balanced soil provides a more favourable environment for roots and healthy plant growth

• Better Soil Structure: The soil becomes looser, more aerated and easier to work, which can reduce the need for deep digging

• Easier Garden Maintenance: Better-structured soil compacts less, is easier to work and can make weeding simpler

• Improved Water Retention: By enriching the soil with humus, compost helps the soil retain moisture more effectively, a valuable asset during dry spells

What Is a Worm Compost Bin?

A vermicomposter is a composting system that uses specific species of worms, such as Eisenia fetida, to break down organic waste. Placed in a suitable container, they gradually consume peelings, coffee grounds and even some unprinted cardboard, transforming them into fine, rich compost.

This system is particularly suitable for flats, as it takes up little space and can be used indoors provided the waste input is well balanced. It does, however, require a little care, as the worms need an environment that is neither too dry nor too damp, and certain types of waste, such as large quantities of citrus fruit, should be avoided.

Making compost is a bit like cooking for the soil: you need the right ingredients, the right balance and a little care. By mixing various organic materials, you feed the microorganisms, worms, and all the tiny creatures that gradually transform them into a substance useful for the garden.

To produce good compost, there are four essential rules:

• Find the Right Balance Between Carbon and Nitrogen: Alternate carbon-rich materials, such as wood chips, straw, dead leaves or unprinted cardboard, with nitrogen-rich materials, such as vegetable peelings, fresh grass clippings, or certain types of animal manure

• Encourage Air Circulation: The organisms in the compost need oxygen to break down the material properly. Bulking agents, such as wood chips or straw, help air to circulate through the heap. Remember to turn your compost regularly with a fork or a rake

• Maintain the Right Moisture Level: The compost must remain moist, without being waterlogged. To check this, take a handful of compost and squeeze it tightly in your hand. A few drops should appear. If water runs out in abundance, it is too wet and if it remains dry and crumbly, it needs more water

• Chop Up Coarse Materials: The finer the material, the more easily it decomposes. Chop or shred branches, thick stems and large pieces of garden waste before adding them to the compost

Good to Know: When done properly, composting generates heat, which helps to break down organic matter. Diseased plants can therefore be added to the compost provided the four rules mentioned above are followed, particularly the balance of inputs, aeration and the rise in temperature.

In practice, home composting can be adapted to your space:

• If You Have a Garden: Set up a wooden or plastic compost bin in a slightly shaded corner, or simply create a compost heap. Gradually add your kitchen waste, garden waste and brown materials, alternating the layers and aerating regularly

• If You Live in a Flat: A worm composter is often the most suitable solution. It can be set up on a balcony, in a small room or under a well-ventilated sink. Add organic waste gradually, without overfilling the bin, to give the worms time to break it down

The materials accepted may vary depending on the composting method chosen: a garden composter, a communal compost heap, a public compost bin, or a worm compost bin. Guidelines may also differ from one local authority to another. Here are the main types of organic waste that can generally be added to a garden composter or a communal compost heap:

• Peelings and Vegetable Scraps: Vegetable, fruit, mushroom, onion, shallot or garlic peelings; citrus fruit cut into small pieces; spoiled plant-based food; leftover rice, pasta or cooked vegetables

• Dry Kitchen Waste: Crushed eggshells, fruit stones, coffee grounds, paper filters, tea bags, leftover tea, and herbal teas

• Food Scraps to Be Added in Small Quantities: Cheese rinds, out-of-date dairy products and stale bread, ideally moistened and crumbled

• Garden Waste: Fallen leaves, dry plants, wilted flowers, grass clippings, hedge trimmings, small twigs, and small pieces of wood

• Other Compostable Materials: Untreated kitchen roll and tissues, human and animal hair, in small quantities

• Diseased Plants: These may only be added if the compost is well-balanced, sufficiently active and managed with care

Caution: In vermicomposting, the list of materials you can add is more restrictive. Citrus fruit, garlic, onions, dairy products and cooked food scraps, for example, should be limited or even avoided, depending on the system used.

Good compost relies on the right balance between wet and dry materials, air and moisture. If it’s too dry, decomposition slows down; if it’s too wet, the heap can become compacted, lack oxygen and give off unpleasant odours. The aim is to achieve a moisture level similar to that of a wrung-out sponge, neither dry nor soggy.

A well-balanced compost heap should not give off unpleasant odours. When a fermenting smell develops, it is often a sign of a lack of air, excess moisture or too much nitrogen-rich material. You should then rebalance the heap by aerating it and adding dry material.

• Turn the Compost Regularly: Turn the compost with a fork or a rake to allow oxygen to circulate and restart the decomposition process

• Alternate Green and Brown materials: Mix moist, nitrogen-rich waste, such as peelings or fresh grass clippings, with dry, carbon-rich materials, such as dead leaves, shredded plant matter or unprinted cardboard

• Monitor the Moisture Level: The compost should remain moist like a wrung-out sponge, without being waterlogged. If it is too dry, water it lightly and if it is too wet, add dry materials and turn it over

• Avoid Unsuitable Additions: Limit meat and fish scraps, fats and heavily processed foods, which can attract pests and cause odours

• Cover Fresh Additions: After each addition of peelings or wet waste, cover with a layer of dry material to keep gnats at bay, absorb excess moisture and maintain a more balanced compost

To speed up decomposition, also remember to cut the waste into small pieces, vary the types of material you add, and ensure the pile is well aerated.

Since 1 January 2024, the French Anti-Waste Law for a Circular Economy (AGEC) has made the sorting of bio-waste at source compulsory. This measure applies to both households and businesses. The aim is to make better use of organic waste and reduce the amount of waste sent for incineration or landfill.

In practical terms, local authorities must provide residents with a suitable solution for sorting their bio-waste. Depending on the local authority, several options may be available:

• The Distribution of Individual Compost Bins: Some local authorities offer free compost bins or a subsidy towards the purchase of one to encourage home composting

• Community Compost Bins: These can be installed at the foot of a block of flats, within a housing estate or at neighbourhood level

• Voluntary Drop-Off Points: These allow residents to deposit their organic waste at dedicated collection points

• Separate Collection of Bio-Waste: Some local authorities organise a specific collection service, separate from household waste

To find out what options are available in your area, contact your local council or your local authority group.

Further Reading

To explore the subject of composting in greater depth, especially within the French context, there are numerous specialised books available, including Je réussis mon compost et lombricompost, published by Terre vivante.

The Terre & Humanisme association also offers courses and training sessions to help people discover the principles of agroecology and best practices in composting.

Finally, numerous organisations support community composting projects in neighbourhoods and housing estates. The Réseau Compost Citoyen, in particular, provides resources and feedback to help residents set up collective solutions.

To make successful compost, ensure you maintain a good balance between wet and dry materials, aerate it regularly and avoid excess moisture, which is often responsible for unpleasant odours. Do not add fats, oils, plastics, metals, so-called ‘compostable’ bags, large pieces of wood or non-organic waste. When vermicomposting, also limit the addition of materials that are irritating or difficult to break down, such as citrus fruit, garlic, or onions.

To ensure your compost is successful, check it regularly: its smell, moisture content, and texture provide good indicators of its balance. Living compost shouldn’t smell bad and it should remain slightly damp, well-aerated and made up of a variety of materials. If in doubt, always add a little dry material, such as dead leaves, shredded wood or unprinted cardboard, then turn it over to kick-start the decomposition process.

Passionate about plants and their properties, she started her career as a perfumer before moving to the world of natural beauty and aromatherapy over 10 years ago. Lucie supports ethical and committed brands with strategy development, product formulation and expert advice for their customers. She has worked with the Aroma-Zone team on several books, including "Le grand guide de l'Aromathérapie et des cosmétiques naturels" ("The Complete Guide to Aromatherapy and Natural Cosmetics"). She also has years of training in aromatherapy, herbalism and essential oil distillation, and supports the work of French plant growers.