UK compost
What compost for long-petalled lewisia in the UK?
Lewisia longipetala
More about long-petalled lewisia in the UK
Which compost long-petalled lewisia needs
For long-petalled lewisia the mix to buy is peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Plant in a very gritty alpine mix (sharp sand and perlite 1:1:1 with loam) and raise the crown well above surrounding soil. Work fine gravel tightly around the collar. Avoid any organic-rich compost that retains summer moisture around the taproot.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 long-petalled lewisia 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?
Long-Petalled Lewisia does not want a rich, water-holding compost — it wants sharp drainage. Cut peat-free multipurpose roughly half-and-half with horticultural grit, sharp sand or perlite, and always pot into a container with drainage holes. A "cactus and succulent" bagged mix is a ready-made shortcut.
For the full recipe, pH and drainage detail (US wording), see the long-petalled lewisia soil & potting-mix guide.
Compost for Long-Petalled Lewisia in the UK — frequently asked questions
What compost should I use for long-petalled lewisia in the UK?
Use peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Plant in a very gritty alpine mix (sharp sand and perlite 1:1:1 with loam) and raise the crown well above surrounding soil. Work fine gravel tightly around the collar. Avoid any organic-rich compost that retains summer moisture around the taproot. 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 long-petalled lewisia?
Not on its own — multipurpose compost holds too much water for long-petalled lewisia and will rot the roots. Cut it roughly 50:50 with horticultural grit, sharp sand or perlite so it drains fast.
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 long-petalled lewisia perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does long-petalled lewisia need grit or perlite added?
Yes — long-petalled lewisia must have sharp drainage. Add about one part horticultural grit or perlite to one part compost, and always use a pot with drainage holes.
What pot and drainage does long-petalled lewisia need?
Always a pot with drainage holes. Sharply drained, lean, slightly acidic to neutral sandy grit (pH 6.5–7.5). 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 long-petalled lewisia care
See the full long-petalled lewisia care guide, its UK watering and UK hardiness.