Daltons Coarse Scoria is a deep red volcanic stone sourced from Taupō. It's hard-wearing but porous and surprisingly light, which makes it one of the most useful stones in the garden: decorative on top, and a drainage helper underneath.
Why scoria?
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Porous: the air pockets in each stone help water drain freely and let air into the root zone.
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Durable: it doesn't break down, so it lasts for years as a ground cover.
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Colour: the rich red contrasts beautifully with silver, blue and green foliage.
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Light: easier to barrow and spread than dense stone of the same size.
Succulent and dry-garden beds
Succulents, cacti, aloes and many Mediterranean plants hate wet feet. Scoria helps in two ways:
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In the soil: build up the bed with Daltons Garden Mix blended with scoria, roughly two parts mix to one part scoria, for a free-draining root zone. Mounding the bed slightly helps water run off in winter.
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On top: finish with a 40–50mm layer of scoria. It keeps moisture away from the base of the plants, where rot usually starts, and looks great against grey-green succulents.
For more on growing them, see All About Succulent Plants.
Pots and containers
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Pot topper: a layer of scoria on top of pots looks smart, reduces evaporation and stops potting mix splashing.
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Better drainage for succulents: mix some scoria through Daltons Potting Mix for succulents and cacti.
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Skip the "drainage layer": a layer of stones in the bottom of a pot doesn't improve drainage and actually raises the wet zone higher in the pot. Mixing scoria through the potting mix works better.
Improving drainage in garden beds
On heavy or clay soils, raising beds is the best long-term fix. Working scoria and Daltons Compost through the top layer of soil helps open it up and improves air and water movement. For bigger drainage problems, see Improving Drainage in Garden Beds.
Decorative ground cover
Laid over weed mat at 40–50mm, scoria makes a vivid, long-lasting ground cover for modern, dry and coastal gardens. It pairs well with black or grey stone and with plants such as flax, astelia, lavender and grasses.
Under the BBQ
Scoria is a classic in charcoal barbecues and drip trays. It spreads heat evenly and catches drips and fat. Replace it when it becomes clogged.
How much do I need?
As a 50mm ground cover, ½ m³ covers about 10 m². For blending into a succulent bed, allow roughly a third of the bed's volume. See How Much Do I Need?
Quick answers
Does scoria fade? It may lighten slightly in strong sun over time, but it keeps its red tones well. Hosing it down refreshes the colour.
Can I walk on scoria? Yes, but it's not as comfortable as smaller rounded stone for a main path. For paths, see How to Build a Gravel Path.
Related reading
