UK compost
What compost for red valerian in the UK?
Centranthus ruber
More about red valerian in the UK
Which compost red valerian needs
For red valerian the mix to buy is peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Prefers lean, chalky or stony ground and tolerates dry walls and crevices. Rich, moist soil produces lush but short-lived, sprawling plants; sharp drainage is key.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 red valerian 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?
Red Valerian 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 red valerian soil & potting-mix guide.
Compost for Red Valerian in the UK — frequently asked questions
What compost should I use for red valerian in the UK?
Use peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Prefers lean, chalky or stony ground and tolerates dry walls and crevices. Rich, moist soil produces lush but short-lived, sprawling plants; sharp drainage is key. 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 red valerian?
Not on its own — multipurpose compost holds too much water for red valerian 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 red valerian perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does red valerian need grit or perlite added?
Yes — red valerian 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 red valerian need?
Always a pot with drainage holes. Poor, gritty, free-draining, alkaline soil, pH 6.5-8.0. 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 red valerian care
See the full red valerian care guide, its UK watering and UK hardiness.