While the sweet potato was first introduced to the UK way back in the 1500s, this root vegetable did not become incredibly popular until much more recently. While they originated in Central and South America, sweet potatoes are in high demand around the world. Believe it or not, farms on British soil have only developed a successful growing technique in the last few years with the first British-grown sweet spuds going on sale in 2015. With this in mind can you grow sweet potatoes in the UK if you are gardening from home? Sweet potatoes require warmer temperatures to thrive, ideally between 21-26ºc. The UK weather doesn’t often give us these temperatures consistently but it may still be possible to grow sweet potatoes in the UK if you use the correct method and mimic their natural growing conditions.

Freshly Lifted Sweet Potato
Affiliate Disclosure

What Type Of Sweet Potato Should I Grow in the UK?

Sweet potatoes come in a huge range of colours. The skin and flesh can vary from anything from purple to orange. If you are looking for a veggie to brighten up your plate then sweet potato is an excellent choice. The great thing about growing sweet potatoes in the UK is that there are several varieties that will prove to be successful such as Georgia Jet, Beauregard Improved, T65 and O’ Henry. However, it is widely accepted that the California Ruby variety is particularly good for growing in this country.

Fresh Sweet Potatoes
Fresh Sweet Potatoes

How To Grow Sweet Potatoes In The UK

While the UK climate might not be the first choice for cultivating sweet potatoes, with the right techniques and a greenhouse at your disposal, you can successfully grow this nutritious tuber. Here’s a guide to growing sweet potatoes in a greenhouse in the UK:

What You Need

  • Slips (young shoots from a mature sweet potato)
  • Well-draining soil
  • A greenhouse or polytunnel
  • Fertiliser (low nitrogen, high potassium)
  • Large pots or containers
  • A watering system or hose
  • Mulch (e.g., straw or black plastic)
  • Garden tools (hoe, spade, gloves)

1 – Choose the Right Variety

While there are numerous sweet potato varieties, the California Ruby variety is particularly well-suited for the UK climate. Its resilience and adaptability make it a top choice for British growers.

2 – Start with ‘Slips’

Instead of seeds, sweet potatoes are grown from ‘slips’ – young shoots that sprout from a mature sweet potato. You can either purchase these from a nursery or cultivate your own by placing a sweet potato in water until it sprouts.

3 – Greenhouse Preparation

  • Temperature Control: Sweet potatoes thrive in temperatures between 21 and 26 degrees Celsius. A greenhouse provides the perfect environment to maintain this temperature range, especially during the unpredictable UK weather.
  • Soil Preparation: Ensure the greenhouse beds have well-drained, fertile soil. Incorporate compost or well-rotted manure to enrich the soil. This ensures the tubers have all the nutrients they need to grow.
  • Spacing: Sweet potatoes have sprawling vines. Plant the slips at least 12 inches apart to give them ample space to grow. If planting in rows, maintain a distance of 30 inches between each row.
Greenhouse in Summer UK
To Grow Sweet Potatoes in the UK, You Need a Greenhouse

4 – Planting

Once the risk of frost has passed, usually in late spring or early summer, plant the slips. Bury them shallowly, ensuring that the leaves remain above the soil. Water them well after planting.

5 – Regular Care

  • Watering: While sweet potatoes need consistent moisture, avoid waterlogging the soil. Water them deeply once a week, ensuring the soil remains moist but not soggy.
  • Ventilation: Greenhouses can get humid. Ensure proper ventilation by opening the doors or vents during the day. This prevents fungal diseases and provides the plants with fresh air.
  • Fertilisation: Feed the plants with an all-purpose fertiliser every three weeks to support their growth.

6 – Harvesting

Sweet potatoes are ready to harvest when their vines turn yellow and start to wilt. This typically happens between 90 to 120 days after planting. Gently dig around the tubers, being careful not to damage them.

7 – Curing and Storage

After harvesting, let the sweet potatoes dry in the sun for a few hours. Then, store them in your greenhouse for about ten days. This curing process helps develop their sweetness and improves their storage life. Once cured, store them in a cool, dark place. They can last for several months when stored correctly.

Freshly Lifted Carolina Ruby Sweet Potatoes
Freshly Lifted Carolina Ruby Sweet Potatoes

Tips For Growing Sweet Potatoes In The UK

These plants do require quite specific care and lots of it but the end result will be more than worth your effort. Take a look at these tips to get the most out of your growing experience.

Tips for Growing Sweet Potatoes in the UK

  1. Watering: Sweet potatoes thrive in well-drained soil. Water them with about an inch weekly for optimal growth. However, hold off on watering during the final weeks before harvest to prevent mature sweet potatoes from splitting.
  2. Ventilation: Ensure good airflow for your sweet potato plants. If you’re using a greenhouse, keep the doors open during the day for proper air circulation.
  3. Managing Growth: Sweet potato vines can sprawl. In a greenhouse, consider tying the stems for a neater appearance. When stems reach 60cm, pinch them out to boost lateral growth.
  4. Fertilising: For a healthy crop, apply an all-purpose fertiliser every three weeks.

How To Harvest Sweet Potatoes In The UK

To harvest your sweet potatoes, you will need to:

  • Choose a Dry Day: It’s best to harvest sweet potatoes when the soil is dry. This makes it easier to remove the tubers and reduces the risk of them rotting if stored with damp soil on them.
  • Dig Gently: Use a fork to gently lift the sweet potatoes from the ground. Start digging from the outer edges of your plant to avoid accidentally piercing any tubers.
  • Handle with Care: Sweet potatoes can bruise easily, so handle them gently. Avoid dropping or tossing them.
Freshly Lifted Sweet Potatoes
Freshly Lifted Sweet Potatoes

How Long Does it Take for Sweet Potatoes to Grow?

Sweet potatoes typically take between 90 to 120 days to mature, depending on the variety and the growing conditions. In the UK, planting is usually done in late spring, meaning that harvest time falls in late summer to early autumn.

How to Know When Your Sweet Potatoes are Ready

There are several indicators that your sweet potatoes are ready for harvest:

  • Foliage Change: One of the most noticeable signs is when the leaves start to yellow or brown. This is a natural indication that the plant is reaching the end of its growth cycle.
  • Size of the Tubers: You can gently dig around the base of one of your plants to check the size of the tubers. If they are of a decent size (typically the size of a large fist or bigger), they are likely ready.
  • Skin Toughness: Gently rub the skin of one of the sweet potatoes. If it doesn’t peel off easily, it’s a good sign that they’re ready for harvest.

How to Store Sweet Potatoes?

If you have a large crop, you may not be ready to eat them all right away.

  • Curing: Once harvested, sweet potatoes benefit from a curing process. This involves storing them in a warm, humid place (like a greenhouse) for about 10-14 days. Curing helps to toughen up their skin and convert starches to sugars, enhancing their flavour.
  • Storage: After curing, store your sweet potatoes in a cool, dark, and dry place. Properly stored, they can last for several months. Ensure they’re kept in a well-ventilated area to prevent rot.
My Sweet Potato Harvest
My Sweet Potato Harvest

Problems with Growing Sweet Potatoes in the UK

Here are some common problems faced by gardeners and potential solutions:

Cool Climate

The UK’s climate is cooler than the sweet potato’s native tropical environment. This can lead to a longer maturation period or, in some cases, failure to mature at all.

Solution: Choose early-maturing varieties suited for cooler climates. Using a greenhouse or polytunnel can also help maintain the warmth sweet potatoes crave.

Poorly Draining Soil

Sweet potatoes prefer well-draining soil. In the UK, where rain is frequent, waterlogged soil can lead to rot.

Solution: Plant sweet potatoes in raised beds or containers filled with well-draining compost. Ensure adequate spacing between plants to prevent water accumulation.

Pests and Diseases

Whitefly, aphids, and sweet potato weevils can be problematic. Fungal diseases, exacerbated by the UK’s damp conditions, can also affect the crop.

Solution: Regularly inspect plants for pests and treat with organic insecticides if necessary. Ensure good airflow around plants and avoid overhead watering to reduce fungal diseases.

Insufficient Sunlight

Sweet potatoes require a lot of sunlight to thrive. In some parts of the UK, especially during overcast days, sunlight can be limited.

Solution: Plant sweet potatoes in the sunniest part of your garden. If using a greenhouse, ensure it’s positioned to receive maximum sunlight.

Short Growing Season

The UK’s growing season might not be long enough for some sweet potato varieties to mature.

Solution: Start slips indoors early in the season to give them a head start. Again, opt for varieties known for quicker maturation.

Unexpected Frosts

Late or early frosts can damage or kill sweet potato plants.

Solution: Keep an eye on the weather forecast. If frost is predicted, cover plants with horticultural fleece or move containers indoors if possible.

What are the Benefits of Eating Sweet Potatoes?

Sweet potatoes are wonderfully healthy and easy-to-prepare food. It’s been shown that sweet potatoes may be linked with cancer-fighting properties, as well as promoting gut health due to their fibre content; this can also help those who suffer from constipation problems! Sweet Potatoes contain antioxidants that promote heart wellness, protect against eye diseases like cataracts, and even aid in brain function. Furthermore, they provide wonderful benefits for the immune system by providing supportive nutrients such as vitamin C or potassium – some of these minerals have been found through research studies to reduce inflammation within cells which helps prevent cell damage caused by free radicals!

Conclusion

Sweet potatoes are an incredibly healthy and versatile root vegetable that has become very popular in recent years. While they are native to Central and South America, sweet potatoes can be grown in the UK, if the grower provides them with the right conditions.

5 Best Sweet Potato Varieties for the UK Infographic

Garden Doctor Tips

“At home in the UK, it is best to grow your sweet potatoes in a greenhouse!”

“Ensure to cure your sweet potatoes so they will last you until you need them!”

“Lift as soon as the stems become a deep yellow colour!”

“Leave your greenhouse door open during the day to let the airflow naturally around your plants!”

Frequently Asked Questions

What month is best to plant sweet potatoes?

Sweet potatoes are a difficult vegetable to grow, but they’re worth the effort. You have to wait for at least 4 weeks after your last frost date before you can plant them – and then allow 150 days of warm, moist weather in order for it to produce well.

Can I grow sweet potatoes from the supermarket?

An organic sweet potato from the supermarket will work just fine. Sweet potatoes grow from seed but rather from a sprout that forms off of old ones! Wait until they’re about 3 inches long before you harvest them by gently pulling them away at their base.

Can you eat sweet potato raw?

Yes, you can eat sweet potato raw. However, it is not as sweet as when it is cooked. Additionally, the nutritional value of sweet potato diminishes when it is eaten raw.

Are sweet potatoes good for you?

Sweet potatoes are incredibly healthy and have as little as 90 calories per 100g serving. They also contain high levels of Vitamins C and A as well as a healthy amount of fibre.


Author

Trevor Wright is not just a seasoned horticulturist; he’s the esteemed Garden Doctor. With a BSc in Horticulture and years of hands-on experience in the soil, Trevor has become a trusted mentor for all things gardening. As the founder of Garden Doctor, he’s committed to clarifying the intricacies of gardening, offering straightforward advice that’s rooted in years of practice. His writing is a garden of how-tos, savvy insights, and comprehensive guides that enable individuals to nurture and grow their garden dreams. When he’s not knee-deep in garden beds, Trevor is at his keyboard passing on his green-thumbed wisdom to budding gardeners, ensuring that the legacy of sustainable and joyful gardening blossoms far and wide.


More You Might Like