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How to choose sustainable materials for your garden

The materials you use in your garden can have a detrimental effect on the environment. Hard landscaping in particular can notch up some seriously high carbon emissions, but luckily there are plenty of eco-friendly alternatives available

Materials for hard landscaping, especially when newly manufactured and transported from the other side of the world, can have have a huge carbon footprint. Some of the most commonly-used materials are also the most carbon hungry. 

Cement – used to make concrete – contributes almost 1kg of carbon dioxide for every 1kg produced, although some is reabsorbed as concrete is exposed to the air. Bricks add 250g per 1kg, and every square metre of stone patio adds about 47.5kg of carbon dioxide, depending on the stone. 

Is wood good?

Wood is the only exception, as long as it’s from managed forests. Look for the Forest Stewardship Council (FSC) or Programme for the Endorsement of Forest Certification (PEFC) mark. 

New wood for building can be carbon neutral, so using it actively helps combat climate change.

Look out for the FSC logo on any new wood products you buy

​Cutting the carbon cost

This award-winning show garden by designer Tony Woods made effective use of recycled and sustainable materials
A sustainably designed garden can still have patios and paths, but they’re kept to a minimum and made from recycled ceramic “gravel” or reclaimed stone slabs. The sustainable garden has pergolas with untreated, locally sourced red cedar, and second-hand garden tables and benches, or handmade items in green oak. Don’t buy materials unless you have to, working with what you already have in the garden.

Sourcing locally helps lower the high carbon cost of transporting heavy items. Second-hand or reclaimed materials from salvage yards carry a fraction of the carbon cost of new ones. They’re also unique and lend your garden a timeless, classic look that’s difficult to achieve with new materials.

New wood for building can be carbon neutral, so using it in the garden actively helps combat climate change.

Sally Nex, author, broadcaster and lecturer

Keeping it natural

Reclaimed and new timber work well together, providing contrast
Treated softwood may be cheaper, but it’s usually preserved with toxic chemicals or heat-treated (with all the carbon emissions that implies).

Instead, use naturally durable timber such as western red cedar or green oak. These have a traditional look and will last for years. Or paint the wood yourself, with a mineral based eco-friendly wood preservative.

​Choosing permeable landscaping

Keep hard-paved areas to a minimum
How you use hard landscaping really matters. Large expanses of paving reflect heat, especially at night, adding to poor air quality and the “heat island” effect in cities.

Paving also contributes to flash flooding by stopping water filtering back into the ground. Keep it to a minimum, use permeable materials like gravel, and maximize rainwater-absorbing planting to create a softer garden, which is gentler on the environment, too.

Sustainable alternatives to concrete

The building industry is currently exploring greener alternatives to conventional cement-based concrete, made from waste materials or biodegradable fibres.

  • Ferrock is made from 90 per cent waste materials, mostly iron dust, which reacts with carbon dioxide to create iron carbonate – therefore actively absorbing carbon from the atmosphere.
  • Timbercrete is a reduced-cement concrete, substituting up to 10 per cent with sawmill waste to make a material that’s about 2½ times lighter than concrete. Available as blocks, bricks, and pavers.
  • Rammed earth is compacted subsoil or chalk packed between temporary panels. You can use it for steps, walls, and even moulded furniture – but in damp climates it can be relatively short lived.

More low-carbon gardening ideas

How to grow a low-carbon garden

How to grow a low-carbon garden

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Grow a potted mini orchard

Planting a low-carbon garden

Planting a low-carbon garden

Make a low-carbon wildflower meadow

Make a low-carbon wildflower meadow

Grow your own garden sundries

Grow your own garden sundries

Low-carbon container growing

Low-carbon container growing

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Combatting climate change through gardening

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RHS How to Garden the Low Carbon Way

Packed with practical gardening solutions to environmental problems and backed by the latest scientific research, RHS How to Garden the Low Carbon Way is perfect for gardeners looking to reduce their carbon footprint.

RHS How to Garden the Low Carbon Way

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