Sweet potatoes
Growing sweet potatoes in the UK is an exciting challenge for the adventurous gardener. They need a long, hot growing season, making a greenhouse or polytunnel almost essential for success.
Sweet potatoes (5 slips)
£8.99 in the shop
Calendar
Sow
February – April, 'slips' (sprouts) started from mature sweet potatoes in water or moist compost.
Plant out
Late May – early June, after all risk of frost has passed, into a greenhouse or very sheltered, sunny spot.
Harvest
September – October, before the first hard frost.
Conditions
Sun
Full sun, 6–8 hours a day
Water
Keep soil consistently moist, especially during tuber development. Reduce watering slightly as harvest approaches.
Soil
Light, sandy, well-draining, pH 5.5–6.5. Avoid heavy, clay soils.
Spacing
30cm between plants, 90cm between rows.
Containers
Possible in large, deep containers (min. 40-50cm deep) or raised beds.
Indoors
Best grown under cover (greenhouse, polytunnel) in the UK for reliable yields. Can be tried outdoors in the warmest, sunniest, most sheltered sites.
Care and harvest
Feeding
A balanced feed every 3-4 weeks once established. Avoid high-nitrogen feeds which encourage leaf growth over tubers.
Pruning
Pinch back vines if they become too vigorous or grow outside their allotted space. Young leaves can be harvested and eaten like spinach.
Harvesting
Dig carefully before the first hard frost. Cure tubers in a warm (25-30°C), humid place for 1-2 weeks to sweeten and extend storage life.
Storage
Store cured sweet potatoes in a cool, dark, well-ventilated place (12-15°C) for several months.
Good companions: Sweetcorn, Oregano, Thyme, Bush beans