UK compost
What compost for crystal palace lobelia in the UK?
Lobelia erinus 'Crystal Palace'
More about crystal palace lobelia in the UK
Which compost crystal palace lobelia needs
For crystal palace lobelia the mix to buy is peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Performs best in fertile soil with good moisture retention and reasonable drainage. In containers use a quality peat-free multipurpose compost mixed with a little perlite for drainage. Avoid heavy clay without amendment, as stagnant moisture encourages root rot and basal stem rot. 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 crystal palace lobelia 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?
Crystal Palace lobelia 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 crystal palace lobelia soil & potting-mix guide.
Compost for Crystal Palace lobelia in the UK — frequently asked questions
What compost should I use for crystal palace lobelia in the UK?
Use peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. Performs best in fertile soil with good moisture retention and reasonable drainage. In containers use a quality peat-free multipurpose compost mixed with a little perlite for drainage. Avoid heavy clay without amendment, as stagnant moisture encourages root rot and basal stem rot. 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 crystal palace lobelia?
Not on its own — multipurpose compost holds too much water for crystal palace lobelia 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 crystal palace lobelia perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does crystal palace lobelia need grit or perlite added?
Yes — crystal palace lobelia 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 crystal palace lobelia need?
Always a pot with drainage holes. Moist, fertile, free-draining loam or all-purpose potting compost. 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 crystal palace lobelia care
See the full crystal palace lobelia care guide, its UK watering and UK hardiness.
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