Going peat-free is great for the environment and the climate, and with so many excellent and readily available peat-free composts now on the market, your plants will be happy too.

Preserving our rare and precious peat bogs is vital, both for the unique biodiversity they support, as well as for the wider environment. They are important carbon stores and draining them for peat extraction releases carbon dioxide, contributing to climate change. They can also play a key role in soaking up excess rainfall, helping to prevent flooding.

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Can refer to either home-made garden compost or seed/potting compost: • Garden compost is a soil improver made from decomposed plant waste, usually in a compost bin or heap. It is added to soil to improve its fertility, structure and water-holding capacity. Seed or potting composts are used for growing seedlings or plants in containers - a wide range of commercially produced peat-free composts are available, made from a mix of various ingredients, such as loam, composted bark, coir and sand, although you can mix your own.

RHS peat policy

RHS peat policy

RHS peat pledge

RHS peat pledge

Peat-free gardening

Peat-free gardening

Peat-free potting composts contain blends of various organic (plant-derived) materials – such as composted bark, coir, woodfibre and green compost – mixed with inorganic materials such as grit, sharp sand, rock wool and perlite. A mix of coarse and fine particles is needed to create a balanced compost that will hold enough water and air, which are essential for root growth.

The three most commonly used organic ingredients are:

• Wood-based materials such as woodfibre, composted bark, sawdust, wood or paper waste are usually the main ingredient. Wood-based mixes can be tailored to the requirements of most plants, as they have excellent drainage properties, as well as a low pH.

• Coir or coconut fibre – this is a waste product, mainly imported from Sri Lanka. It has excellent water-holding abilities and a sufficient mix of fine and coarse fibres to hold air in its pore spaces, to provide good growing conditions. However it doesn’t hold nutrients well. The environmental credentials of coir are debatable, due to the distance it has to be transported, but this is balanced out by the fact that it is a genuine waste material.

• Green compost – many local authorities and private companies collect and compost green waste. The resulting compost tends to have a high nutrient content and high pH, making it an excellent soil improver or mulch. There is an industry standard (British Standards Institution PAS100) for green compost that enforces consistent and regulated processing, in order to encourage its use in potting composts. Due to its high pH and high levels of nutrients, green compost tends to be mixed with other materials to make potting compost – it’s usually no more than 30 per cent of the overall product.

Other ingredients
Research is ongoing into a number of materials that, if locally available, may be useful ingredients in blended products, such as arable straw waste, wool waste, carpet waste, and paper and cardboard production waste.

Home-made potting compost
You can mix your own peat-free potting compost using home-made garden compost, leafmould and inorganic materials (loam and sand). This has the great benefits of being free and having no carbon footprint, but the results can be variable – it can be difficult to standardise the pH, moisture retention and available nutrients, and to ensure that the final mix is weed-free. 

Composting

Composting

Leafmould

Leafmould

Alternatives to peat

Alternatives to peat

• Multi-purpose and seed compost – most of the major manufacturers produce peat-free multi-purpose products, including SylvaGrow and Westland New Horizon

• Ericaceous compost –  the choice for ericaceous (acid-loving) plants is more limited, but look for SylvaGrow Ericaceous

• John Innes compost – for containers that will be home to plants for more than two or three years, use a peat-free John Innes compost such as SylvaGrow with John Innes. But note that traditional-recipe John Innes contains peat

• Carnivorous plant compost – though these bog plants are traditionally grown in peat, sustainable options have been developed in recent years, such as milled bark, other fibrous materials such as coir, or live sphagnum moss, combined with sharp sand, perlite or vermiculite. In fact, RHS research has now shown that carnivorous plants can be grown more successfully in peat-free mixes than in peat.

RHS endorsed Melcourt products

RHS endorsed Melcourt products

• If the bag doesn’t say peat-free, then it most likely isn’t

• Words such as ‘environmentally friendly’ and ‘organic’ may lead you to think a product is peat-free, but they don’t actually mean that it is

• A good-quality peat-free compost is usually a little more expensive – price does tend to reflect quality

• Check the information on the bag to see if it’s recommended for particular uses or plant groups (such as seed sowing or growing bedding plants)

When buying plants, you may also wish to consider choosing plants that have been grown peat-free. Our list of peat-free nurseries is here to help you source more sustainably grown plants that have been raised 100% peat-free.