Organic gardening avoids synthetic pesticides, weedkillers and fertilisers, and relies on feeding the soil with compost and encouraging the predators that keep pests in check.
Peat-free compost, mulching, barriers, resistant varieties and biological controls replace most of what chemicals once did.
Organic gardening means growing without synthetic pesticides, weedkillers or manufactured fertilisers. In practice it is less a list of prohibitions than a method: the soil is fed, natural predators are encouraged, and problems are prevented where possible instead of treated afterwards.
For food sold as organic, the word is defined in law and producers are inspected by an approved certification body. No such rules bind a home gardener, and the term is used loosely. The principles most widely followed in Britain are those published by the charity Garden Organic, founded in the 1950s as the Henry Doubleday Research Association.
The range of chemicals on sale to home gardeners has in any case narrowed. Many garden pesticides have been withdrawn in Britain and the European Union since the 2000s, among them metaldehyde slug pellets, which were banned for outdoor use in Great Britain in 2022.
Organic growing rests on the idea that a soil rich in organic matter and living organisms grows healthy plants. Garden compost, leaf mould and well-rotted manure are added every year, dug in or laid on the surface as a mulch. A mulch 5 cm or more deep also suppresses weeds and slows evaporation.
Green manures are crops such as phacelia, clover, field beans and grazing rye that are sown on empty ground and cut down before they set seed. They protect bare soil from winter rain, and the clover and bean family adds nitrogen.
Manure from farms and stables occasionally carries residues of weedkillers used on pasture, which distort the growth of beans, tomatoes and potatoes. Asking the supplier what was sprayed, or testing a sample by sowing a few beans in it, avoids the problem.
Where extra feeding is needed, organic gardeners use materials of plant or animal origin, such as seaweed meal, pelleted chicken manure, and blood, fish and bone. Liquid feeds are made by steeping comfrey or nettle leaves in water for several weeks; comfrey is high in potash and suits tomatoes and other fruiting crops.
Peat is avoided. Peat bogs hold large amounts of carbon and support specialised wildlife, and extraction destroys both. The UK government announced in 2022 that retail sales of peat compost in England would be banned, though the legislation had still not been passed by early 2026; many retailers have withdrawn it voluntarily.
Without weedkillers, weeds are controlled by hoeing on dry days, hand weeding, mulching and close planting that shades the soil. Perennial weeds such as bindweed and ground elder are weakened by repeated removal of the top growth, or killed by covering the ground with cardboard or opaque sheeting for a full growing season.
The organic approach accepts some damage and relies on balance. A garden with a pond, long grass, flowers and undisturbed corners supports frogs, hedgehogs, birds, ground beetles, ladybirds, hoverflies and lacewings, all of which eat pests; the guide to gardening for wildlife describes how to attract them.
Beyond that, the main methods are:
Mains water is treated to drinking standard, which takes energy. Water butts fitted to downpipes collect rain from house, shed and greenhouse roofs, and rainwater is better than hard tap water for acid-loving plants such as blueberries and camellias. Watering in the evening or early morning, at the base of plants, loses least to evaporation.
A garden does not need to change all at once. Stopping the use of pesticides and weedkillers, switching to peat-free compost and starting a compost heap are the usual first steps. Pest numbers sometimes rise in the first year or two before predators build up.