How to Grow Sweet Potatoes UK
On this page
- Sweet Potato (Ipomoea batatas)
- When to Plant Sweet Potatoes in the UK
- Quick Facts
- At a Glance
- Soil & Growing Conditions
- Growth Stages
- Harvest & Storage
- Diseases
- Pests
- Nutrient Issues
- Sweet Potato, Slip to Harvest
- Plan your Sweet Potatoes planting
- Growing Sweet Potato in another region
- References
- Frequently Asked Questions
In the UK, sweet potatoes are sown early April to late April, planted out mid May to mid June, and are ready to harvest 100–150 days after sowing.
Timing is the decision that matters most in the UK: there are 4 separate regional planting out windows, ranging from mid May in Southern England to early June in Scotland.
The short answer
- Sow
- Early April to late April
- Plant out
- Mid May to mid June
- Ready in
- 100–150 days
- Site
- 6+ hours of sun, soil pH 5–7
- Biggest risk
- Sweetpotato black rot
Core growing advice on this page is checked against named horticultural sources — see References.
Sweet Potato (Ipomoea batatas)
9 sources cited · Verified
When to Plant Sweet Potatoes in the UK
When to plant sweet potatoes in the UK: in Southern England, sow early April to late April and plant out mid May to mid June. Find your area in the table below.
| Region | Sow | Plant out |
|---|---|---|
| Southern England | early April to late April | mid May to mid June |
| Midlands derived | mid April to mid May | late May to late June |
| Northern England derived | late April to late May | early June to late June |
| Scotland derived | early May to early June | early June to early July |
Rows marked derived are interpolated between regions our sources do state, because no source we consulted gives a figure for that region specifically. They are deliberately wider to reflect that uncertainty.
Southern England - detail & sources
Southern England: RHS gives no region-specific UK date, only "late spring or early summer, once the last frost has passed" -- this is the baseline reading of that rule for the mildest, earliest-clear UK region. Slips are potted up under cover from April and hardened off before planting out.
Midlands - detail & sources
Midlands: derived a week or so later than southern England, reflecting a later average last-frost date -- interpolated, since RHS gives one UK-wide rule rather than per-region dates.
Northern England - detail & sources
Northern England: derived later again for a later, more variable last frost -- interpolated from the RHS rule rather than a region-specific source.
Scotland - detail & sources
Scotland: derived to the latest and narrowest window in the UK -- a genuinely tender tropical crop this far north needs the surest possible frost clearance and the longest realistic run to a four-to-five month harvest before autumn frost, which for many Scottish gardens means growing under glass throughout rather than planting out at all. Interpolated from the RHS rule.
Quick Facts
| Factor | Value |
|---|---|
| Soil pH | 5 - 7 |
| Sunlight | 6-6 hours direct sun |
| Germination temp | 24°C |
| Optimal growing temp | 18-28°C |
| Minimum survivable temp | 1°C |
| Time to harvest | 100-150 days |
| Drainage | Moisture-retentive, free-draining |
| Lifecycle | perennial |
| Edible parts | storage roots |
At a Glance
Soil & Growing Conditions
Soil pH range
Span reflects genuine variation between the cited authorities, not a single agreed figure.
Growth Stages
| Stage | BBCH | Notes |
|---|---|---|
| Slips & establishment | 0 | Grown from rooted cuttings ("slips") rather than seed tubers, available from online veg plant suppliers from late April. Pot up and grow on under cover until frost risk has passed. RHS. |
| Planting out | 3 | Plant out at least 30cm apart in late spring or early summer, once all frost risk has passed. The crop is tender throughout and must be protected from frost; it thrives at 21-26°C, which is why it is best grown under cover in the UK -- a greenhouse, or cloches and fleece outdoors. RHS. |
| Vining growth | 6 | Trailing or climbing stems easily reach 1.5m or more in length as the plant bulks up through summer, well before any sign of the tubers developing below. RHS. |
| Harvest & curing | 8 | Most varieties need at least four to five months from planting; "Bonita" takes about 100 days. Harvest once the leaves yellow and die back in early autumn, before any frost -- tip the plant out of its container or lift with a fork. Dry tubers in warm sunshine for a few days to improve storage, though they generally keep for only a few weeks. RHS. |
Harvest & Storage
When to pick: RHS: "Bonita" takes "about 100 days from planting slips to harvesting"; most varieties require "at least four to five months"; harvest "once the leaves turn yellow and die back in early autumn, before any frost". UMD: days to maturity "85 to 120"; check root size "after 80 to 85 days because they don't stop growing"; roots "can start to split when overgrown"; harvest "before a frost".
Storage
Cure and store in cool, dry conditions for long-term keeping
Diseases
Pests
Nutrient Issues
Sweet Potato, Slip to Harvest
Plan your Sweet Potatoes planting
When to sow and plant Sweet Potatoes depends on your own frost dates. Check the UK vegetable planting calendar. To work out where it fits in your beds, sketch your plot in the free Garden Layout Planner.
Growing Sweet Potato in another region
Sowing dates, frost timing and local advice differ by country. Use the guide for where you garden.
References
-
RHS factsheet on glasshouse red spider mite (two-spotted spider mite), naming tomato and strawberry among the host plants affected under glass or in a polytunnel.
-
RHS explicitly distinguishes yellow sticky traps as a monitoring tool rather than a standalone control method, and notes traps also catch non-target parasitoid wasps -- a genuine trade-off between two control methods, preserved rather than simplified. No specific pesticide/insecticidal soap product is named on this page (RHS links out to a general pesticides statement instead), so none is recorded here.
-
General cross-plant guide, strawberry named explicitly under Boron.
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Grown from SLIPS -- sprouted sweet potato roots, raised by suspending a root in water or bedding roots in sand under warmth; slips are ready to pull in about 6 weeks, once rooted and 6-8in tall. Plant out after all frost danger; keep soil 70-80°F during sprouting. Space slips 12in apart in rows 36-48in apart, on 8-10in raised beds for drainage and root development, in fertile, moist, well-drained, nutrient-rich soil. Drought tolerant but grows best with ample water after planting; LATE WATERING CAUSES ROOT CRACKING, so water moderately as plants mature. Roots mature in 4-5 months (varieties 90-135 days); harvest at 1.5-2in thick. Cure 1-2 weeks at 80°F then store cool and dry at 50-55°F, keeping 3-4 months when properly cured. Pests: flea beetles, cutworms. Diseases: scurf, black rot.
9 independent sources are cited for this crop. Where they disagree - soil pH is the clearest case - every figure is preserved rather than averaged into false precision.
Frequently Asked Questions
When should I plant sweet potatoes out in the UK?
In Southern England, from mid May. In Scotland, wait until early June. Treat these as a guide rather than a fixed date — the governing rule is to plant out only once frost risk has passed and temperatures are reliably warm enough.
When do I sow sweet potatoes?
Sow early April to early June, at around 24°C for germination.
How long do sweet potatoes take to grow?
Typically 100–150 days, depending on cultivar and growing conditions.
What soil pH do sweet potatoes need?
A pH of about 5–7. That span reflects genuine variation between the authorities we cite rather than a single agreed figure — the References section lists each source's exact range.
What problems affect sweet potatoes?
Our data links 2 diseases and 2 pests to this crop. See the sections above for each one and how to manage it.
Plan next season before the problems start
Most of the advice on this page comes down to timing and spacing — sowing at the right moment, rotating beds, and giving plants enough airflow. The UK Garden Planner lays your plot out month by month so those decisions are already made before the season starts.
Get the UK Garden Planner →Instant PDF download · Written for UK growing conditions
How this guide is put together
The growing data on this page — sowing windows, pests, diseases, soil and site requirements — comes from named horticultural sources, listed in References below, checked against RHS and Met Office guidance. An automated pipeline assembles that verified data into the page you're reading: it selects which facts to lead with and builds the surrounding prose and layout. It does not invent a date, a source or a number — where a verified value for a field isn't available, the page leaves it out rather than guessing. A person reviews and publishes each page; nothing goes live unverified.
Last verified 2026-09-02
Plan Sweet Potatoes by month
The months this guide gives for sowing or planting, each with the full list of jobs for that month in the UK:
More from the same group (roots & tubers):
Growing advice for your part of the UK
Timing and conditions change a lot inside one country. These guides cover frost dates and growing seasons region by region.
Where To Go From Here
Take this crop from reading into a written plan for your own beds.
Keep going
Plan the next step
Use the printable SoilCommander planner for your region to turn this guide into sowing dates, bed layouts and weekly garden tasks.