Sweet Potato

A vigorous, sprawling vine that needs a genuine UK summer to reward you: warmed soil, full sun and steady watering, in exchange for your own harvest of tubers by early autumn. Choose a UK-bred variety like Beauregard rather than a supermarket root, and don't expect it to look after itself: this is a thirsty crop, not a drought-tolerant one.

Written by Yemi · Last reviewed August 2026

Maturing this month

First sprouts in 2–3 weeks to root and establish after potting up a slip

Difficulty

Sweet Potato should be ready to harvest this month. Check for size and colour.

Growing Calendar

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Sow

Transplant

Harvest

This month: Sep

Log to journal

Ready to harvest now

•Check size and ripeness
•Harvest regularly
•Store or use fresh

Sowing Guide

What you'd find on the seed packet

Sow Depth

Pot slips at the same depth they arrive, then bury the stem up to the base of the leaves when planting out to encourage rooting along its length

Spacing

At least 30cm between plants

Germination

2–3weeks to root and establish after potting up a slip

Thinning

Not applicable: one slip per planting station

Grower's Note

Slips are available by mail order from late April, or root your own from a UK-variety tuber: place in moist sand somewhere warm until shoots appear, then cut and root 5–7.5cm shoots in compost. Avoid supermarket sweet potatoes as a source: most are unsuited tropical varieties.

Recommended Varieties

'Beauregard' is the variety most consistently recommended for UK outdoor growing by both RHS and UK seed suppliers. 'Bonita' crops faster, in around 100 days. 'Erato White' and 'Erato Violet' are UK-bred alternatives.

Planting Out Guide

Best spaces, conditions and how to plant out

Plant Spacing

30cm apart, in rows or a sprawling bed with room to spread

Best Grown In

Open ground, raised beds, or a large container; a polytunnel or greenhouse border gives the most reliable UK results

Conditions

Full sun. Warm the soil for a few weeks beforehand with cloches, fleece or black plastic, and don't plant out until night temperatures are reliably above 15°C.

Grower's Note

Water consistently all summer: this is a thirsty crop that will underperform if left to dry out, not one that thrives on neglect. Lift the whole crop before the first autumn frost.

Growing Stages

Approximate weeks from sowing to harvest

Sprouting

3wks

Seeds germinate and first leaves emerge. Keep warm and moist.

Establishing

10wks

Root system develops and plant builds structure. Pot on if needed.

Maturing

7wks

Plant reaches full size and begins producing. Harvest at peak.

Total~20 weeksfrom seed to harvest

Companion Plants

Plant these nearby for natural pest control, better yields, and healthier soil.

Beans

Fixes Nitrogen

Beans fix nitrogen from the air into the soil as they grow, feeding a hungry, vigorous neighbour like Sweet Potato.

Marigold

Repels Pests

Marigold's roots help suppress soil nematodes, a problem sweet potato shares with its relative, ordinary potato.

Climate Control

Today

—C

Humidity

—%

Water

Daily

Sunlight

6+ hours direct sun

Watch Out For

Slugs and snails are the biggest UK threat, tunnelling into developing tubers underground: protect with copper tape, beer traps, or a nematode treatment in August

A UK summer barely gives enough warmth and season length: choose a UK-recommended variety like Beauregard rather than a supermarket sweet potato, which is often an unsuited tropical cultivar

Frost kills the foliage fast and damages tubers still in the ground: lift the whole crop in September or October, well before the first autumn frost, regardless of how the calendar looks

What You'll Need

Equipment for growing sweet potato

Modular Seed Tray

96-cell for precision sowing

Fine Rose Watering Can

Gentle shower for seedlings

Bamboo Canes

Pack of 20 × 120cm

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Grown Organically

Every method in this guide works with natural systems: no synthetic chemicals, no shortcuts.

Read our approach

Common Questions

About growing Sweet Potato in the UK

When should I plant sweet potato slips in the UK?

Plant out from late May to the end of June, once the last frost has passed and night temperatures are reliably above 15°C. Pot up bought or home-rooted slips indoors for two to three weeks first, and warm the soil beforehand with cloches, fleece or black plastic.

Can I grow sweet potatoes from a supermarket tuber?

It's possible but not recommended: most supermarket sweet potatoes are tropical varieties bred for warmer climates, not suited to a UK growing season. Buy slips, or root your own from a UK-bred variety like Beauregard, for a far more reliable crop.

Does sweet potato need a lot of water?

Yes. Despite sometimes being described as low-maintenance, sweet potato is a genuinely thirsty plant that needs consistently moist soil all summer. Let it dry out and both vine growth and tuber size will suffer.

When is sweet potato ready to harvest?

From September to October, roughly four to five months after planting out, once the leaves begin to yellow. Always lift the whole crop before the first autumn frost: frost damages both foliage and the tubers still in the ground.

Written from real growing experience, not just research. Read the story behind Pelham Gardens.

Member guides

There's more to growing Sweet Potato than this guide covers.

A Garden Journal to log what worked, a personalised sowing planner in My Garden, and monthly reminders timed to the calendar.

See what's included