UK compost
What compost for salvia verticillata 'purple rain' in the UK?
Salvia verticillata 'Purple Rain'
More about salvia verticillata 'purple rain' in the UK
Which compost salvia verticillata 'purple rain' needs
For salvia verticillata 'purple rain' the mix to buy is peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Adaptable to average soil with neutral to slightly alkaline pH. Needs reliable drainage, especially over winter; loosen heavy clay with grit.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 salvia verticillata 'purple rain' 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?
Salvia verticillata 'Purple Rain' 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 salvia verticillata 'purple rain' soil & potting-mix guide.
Compost for Salvia verticillata 'Purple Rain' in the UK — frequently asked questions
What compost should I use for salvia verticillata 'purple rain' in the UK?
Use peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Adaptable to average soil with neutral to slightly alkaline pH. Needs reliable drainage, especially over winter; loosen heavy clay with grit. 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 salvia verticillata 'purple rain'?
Not on its own — multipurpose compost holds too much water for salvia verticillata 'purple rain' 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 salvia verticillata 'purple rain' perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does salvia verticillata 'purple rain' need grit or perlite added?
Yes — salvia verticillata 'purple rain' 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 salvia verticillata 'purple rain' need?
Always a pot with drainage holes. Well-drained, moderately fertile loam. 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 salvia verticillata 'purple rain' care
See the full salvia verticillata 'purple rain' care guide, its UK watering and UK hardiness.