Sweet potatoes need warmth, sunshine and a long season, so British crops are most reliable in a greenhouse, polytunnel or exceptionally sheltered southern garden. Their trailing vines can still yield useful tubers outdoors when grown on warmed ridges. 'Beauregard' is a dependable choice for UK conditions.

When and how to sow

Buy healthy slips, which are rooted cuttings, and plant only after frost has passed, usually in late May or June. In cooler regions, start under cover and use a greenhouse or polytunnel. Set slips 35 cm apart on raised, warmed ridges, or through black mulch in the warmest outdoor bed. Use loose, free-draining soil enriched modestly with garden compost, allowing 90 cm between rows.

Care

Water slips regularly until rooted, then keep soil evenly moist during dry spells without saturating it. Guide trailing stems within their row and weed early, before vines cover the soil. A warm mulch helps outdoor crops, while greenhouse plants benefit from ventilation. Avoid excessive feeding, which favours leaves over tubers.

Common problems

Slugs are the usual nuisance, feeding on new foliage and young stems, so inspect plants frequently and keep surrounding areas tidy. Cold, wet soil can lead to poor growth or rotting roots. Give outdoor plants warmth with black mulch or a cloche early on, then remove covers when growth becomes vigorous.

Harvest

Lift tubers carefully before the first autumn frost, generally from September to October, using a fork well away from the main stem. Handle skins gently and cure roots for around ten days in a warm, airy place. Store cured tubers dry and frost-free, rather than in a cold refrigerator.

Growing Sweet Potatoes: frequently asked questions

When should I sow sweet potatoes in the UK?

Buy healthy slips, which are rooted cuttings, and plant only after frost has passed, usually in late May or June.

What are common problems when growing sweet potatoes?

Slugs are the usual nuisance, feeding on new foliage and young stems, so inspect plants frequently and keep surrounding areas tidy.

When is sweet potatoes ready to harvest?

Lift tubers carefully before the first autumn frost, generally from September to October, using a fork well away from the main stem.

General guidance for UK home gardens and allotments. Reference figures are typical values; your exact timing depends on your region, last-frost date and variety. Page updated 19 Sep 2026.