UK compost
What compost for giant mondo grass in the UK?
Ophiopogon jaburan
More about giant mondo grass in the UK
Which compost giant mondo grass needs
For giant mondo grass the mix to buy is peat-free multipurpose compost. Grows in a wide range of well-drained soils. Enriching with compost or leafmould promotes vigorous growth. Prefers slightly acidic to neutral pH (5.5–7.0). Avoid waterlogged conditions.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 giant mondo 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?
Giant Mondo 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 giant mondo grass soil & potting-mix guide.
Compost for Giant Mondo Grass in the UK — frequently asked questions
What compost should I use for giant mondo grass in the UK?
Use peat-free multipurpose compost. Grows in a wide range of well-drained soils. Enriching with compost or leafmould promotes vigorous growth. Prefers slightly acidic to neutral pH (5.5–7.0). Avoid waterlogged conditions. 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 giant mondo grass?
Yes. A good peat-free multipurpose compost is exactly right for giant mondo 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 giant mondo 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 giant mondo 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 giant mondo grass need?
Always a pot with drainage holes. Fertile, moist, well-drained loam; neutral to slightly acidic. 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 giant mondo grass care
See the full giant mondo grass care guide, its UK watering and UK hardiness.