UK compost
What compost for straight-leaved butterwort in the UK?
Pinguicula rectifolia
More about straight-leaved butterwort in the UK
Which compost straight-leaved butterwort needs
For straight-leaved butterwort the mix to buy is peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Use a fast-draining, nutrient-poor mineral mix: equal parts perlite, vermiculite, coarse horticultural sand, and a small amount of pumice or volcanic lava. Avoid peat-heavy mixes and never use standard potting compost or fertilised media. Shallow terracotta or plastic pots with drainage holes are suitable.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 straight-leaved butterwort 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?
straight-leaved butterwort 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 straight-leaved butterwort soil & potting-mix guide.
Compost for straight-leaved butterwort in the UK — frequently asked questions
What compost should I use for straight-leaved butterwort in the UK?
Use peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Use a fast-draining, nutrient-poor mineral mix: equal parts perlite, vermiculite, coarse horticultural sand, and a small amount of pumice or volcanic lava. Avoid peat-heavy mixes and never use standard potting compost or fertilised media. Shallow terracotta or plastic pots with drainage holes are suitable. 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 straight-leaved butterwort?
Not on its own — multipurpose compost holds too much water for straight-leaved butterwort 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 straight-leaved butterwort perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does straight-leaved butterwort need grit or perlite added?
Yes — straight-leaved butterwort 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 straight-leaved butterwort need?
Always a pot with drainage holes. Mineral carnivorous plant mix. 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 straight-leaved butterwort care
See the full straight-leaved butterwort care guide, its UK watering and UK hardiness.