UK compost
What compost for common saltmarsh grass in the UK?
Puccinellia maritima
More about common saltmarsh grass in the UK
Which compost common saltmarsh grass needs
For common saltmarsh grass the mix to buy is peat-free multipurpose compost. Colonises the upper and mid intertidal zone on fine clay-silt substrates; it produces a dense, mat-forming turf that binds the surface of developing saltmarsh and reduces erosion.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 common saltmarsh grass 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?
Common Saltmarsh Grass is straightforward: an ordinary peat-free multipurpose compost is right. For a big specimen or a pot it will live in for years, mixing in some loam-based John Innes No.2 or No.3 adds weight and holds nutrients longer. Ericaceous compost is not needed unless a plant is specifically a lime-hater.
For the full recipe, pH and drainage detail (US wording), see the common saltmarsh grass soil & potting-mix guide.
Compost for Common Saltmarsh Grass in the UK — frequently asked questions
What compost should I use for common saltmarsh grass in the UK?
Use peat-free multipurpose compost. Colonises the upper and mid intertidal zone on fine clay-silt substrates; it produces a dense, mat-forming turf that binds the surface of developing saltmarsh and reduces erosion. 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 common saltmarsh grass?
Yes. A good peat-free multipurpose compost is exactly right for common saltmarsh grass. For a large or long-term pot you can mix in some John Innes No.2 or No.3 (loam-based) for extra weight and staying power.
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 common saltmarsh grass perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does common saltmarsh grass 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 common saltmarsh grass need?
Always a pot with drainage holes. Saline, fine-grained mud or silty clay, periodically waterlogged. 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 common saltmarsh grass care
See the full common saltmarsh grass care guide, its UK watering and UK hardiness.