UK compost
What compost for petunia 'wave purple' in the UK?
Petunia × atkinsiana 'Wave Purple'
More about petunia 'wave purple' in the UK
Which compost petunia 'wave purple' needs
For petunia 'wave purple' the mix to buy is peat-free ericaceous (lime-free) compost. Use a quality multipurpose compost for containers or fertile, well-drained soil in beds, ideally pH 5.5-6.5. Good drainage prevents root rot; in heavy ground add organic matter and 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 petunia 'wave purple' 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?
Petunia 'Wave Purple' is a lime-hater: it needs an acidic, lime-free ericaceous compost. In ordinary (limey) multipurpose it slowly yellows between the leaf veins as it locks out iron. Buy a bag labelled "ericaceous", and in a hard-water area water with rainwater where you can, since tap water is slightly alkaline.
For the full recipe, pH and drainage detail (US wording), see the petunia 'wave purple' soil & potting-mix guide.
Compost for Petunia 'Wave Purple' in the UK — frequently asked questions
What compost should I use for petunia 'wave purple' in the UK?
Use peat-free ericaceous (lime-free) compost. Use a quality multipurpose compost for containers or fertile, well-drained soil in beds, ideally pH 5.5-6.5. Good drainage prevents root rot; in heavy ground add organic matter and 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 petunia 'wave purple'?
No — petunia 'wave purple' needs an acidic, lime-free (ericaceous) compost. Standard multipurpose is too limey and will slowly cause yellowing between the leaf veins (lime-induced chlorosis). Buy a bag labelled "ericaceous".
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 petunia 'wave purple' perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does petunia 'wave purple' 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 petunia 'wave purple' need?
Always a pot with drainage holes. Rich, free-draining, slightly acidic potting or garden soil. 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 petunia 'wave purple' care
See the full petunia 'wave purple' care guide, its UK watering and UK hardiness.