UK compost
What compost for purging jatropha in the UK?
Jatropha cathartica
More about purging jatropha in the UK
Which compost purging jatropha needs
For purging jatropha the mix to buy is peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. A blend of 50% inorganic material (coarse perlite, pumice, or coarse grit) with 50% succulent potting mix is ideal. The caudex is highly susceptible to rot in moisture-retaining or clay-based soils. Tolerates slightly alkaline pH (7.0–8.0).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 purging jatropha 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?
Purging Jatropha 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 purging jatropha soil & potting-mix guide.
Compost for Purging Jatropha in the UK — frequently asked questions
What compost should I use for purging jatropha in the UK?
Use peat-free multipurpose compost cut roughly half-and-half with horticultural grit or perlite. A blend of 50% inorganic material (coarse perlite, pumice, or coarse grit) with 50% succulent potting mix is ideal. The caudex is highly susceptible to rot in moisture-retaining or clay-based soils. Tolerates slightly alkaline pH (7.0–8.0). 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 purging jatropha?
Not on its own — multipurpose compost holds too much water for purging jatropha 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 purging jatropha perfectly well — they dry a little faster at the surface, so check moisture by feel rather than by the look of the top.
Does purging jatropha need grit or perlite added?
Yes — purging jatropha 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 purging jatropha need?
Always a pot with drainage holes. Highly gritty, fast-draining succulent or cactus 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 purging jatropha care
See the full purging jatropha care guide, its UK watering and UK hardiness.