UK compost
What compost for rough-shelled macadamia in the UK?
Macadamia tetraphylla
More about rough-shelled macadamia in the UK
Which compost rough-shelled macadamia needs
For rough-shelled macadamia the mix to buy is peat-free ericaceous (lime-free) compost. Prefers pH 5.0-6.5. The proteoid root mat needs friable, well-aerated soil; it dislikes heavy clay, alkalinity, and salt.In British garden centres the bagged growing medium is sold simply as “compost” (multipurpose, ericaceous, or loam-based John Innes), which is a different thing from the rotted garden “compost” you make in a heap — for a pot you want the bagged kind.
Peat-free compost
Buy peat-free. The sale of peat compost to home gardeners is being phased out across the UK, and the RHS recommends peat-free on environmental grounds. A good peat-free multipurpose grows rough-shelled macadamia perfectly well; the one habit to change is watering — peat-free dries faster at the surface while still moist below, so check by feel a knuckle deep rather than trusting the look of the top.
Ericaceous or multipurpose?
Rough-Shelled Macadamia is a lime-hater: it needs an acidic, lime-free ericaceous compost. In ordinary (limey) multipurpose it slowly yellows between the leaf veins as it locks out iron. Buy a bag labelled "ericaceous", and in a hard-water area water with rainwater where you can, since tap water is slightly alkaline.
For the full recipe, pH and drainage detail (US wording), see the rough-shelled macadamia soil & potting-mix guide.
Compost for Rough-Shelled Macadamia in the UK — frequently asked questions
What compost should I use for rough-shelled macadamia in the UK?
Use peat-free ericaceous (lime-free) compost. Prefers pH 5.0-6.5. The proteoid root mat needs friable, well-aerated soil; it dislikes heavy clay, alkalinity, and salt. In UK garden centres this is sold simply as "compost" — the bagged growing medium, not garden-made leaf-mould — so match the description above rather than a brand.
Can I use ordinary multipurpose compost for rough-shelled macadamia?
No — rough-shelled macadamia needs an acidic, lime-free (ericaceous) compost. Standard multipurpose is too limey and will slowly cause yellowing between the leaf veins (lime-induced chlorosis). Buy a bag labelled "ericaceous".
Should the compost be peat-free?
Yes. Sales of peat compost to home gardeners are being phased out in the UK, and the RHS recommends peat-free for environmental reasons. Modern peat-free multipurpose composts grow rough-shelled macadamia perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does rough-shelled macadamia need grit or perlite added?
Not essential, but a couple of handfuls of perlite in the mix improves aeration and guards against overwatering — useful on a cool, damp British windowsill where compost stays wet longer.
What pot and drainage does rough-shelled macadamia need?
Always a pot with drainage holes. Deep, fertile, free-draining acidic loam with high organic matter. Stand it on a saucer, empty any water that collects after watering, and never leave the pot sitting in a full outer cover — waterlogged compost in a cool UK room is the commonest cause of root rot.
More rough-shelled macadamia care
See the full rough-shelled macadamia care guide, its UK watering and UK hardiness.