Sweet Potatoes

It will never work… but I bought two Sweet Potatoes to ‘chit’… then we used one for supper because we decided a) it won’t work, they are too difficult to chit and then keep alive in England and b) if it DID work, we didn’t want that many! They were giant… 

Sweet Potatoes are famously difficult to grow in England because of our bad weather in comparison to South America or Africa where they thrive. We should really stick to our normal potatoes, which is fine by me because I think they go with more meals, but it is fun to try out these new vegetables. Despite its name and look, sweet potatoes are nothing like potatoes. They taste different, are from a different family etc. They are a completely different vegetable hence why we decided we might as well give it a go and try growing one despite the odds being pretty much stacked against us! If you buy your sweet potatoes to grow properly online (which is probably better than me getting one from the market, this process has a very poor succession report) then they will arrive often as plug-plants to make things easier. Read on to find out some interesting history, nutrition and how to grow facts about sweet potatoes, as well as a yummy recipe at the bottom… 

Sweet Potato (Ipomoea batatas) is a dicotyledonous plant that belongs to the morning glory family Convolvulaceae. Its large, starchy, sweet-tasting, tuberous root are a root vegetable. They are also known as yams (although the soft, orange sweet potato is often called a “yam” in parts of North America, the sweet potato is botanically very distinct from a genuine yam (Dioscorea), which is native to Africa and Asia and belongs to the monocot family Dioscoreaceae), or kumara. Sweet potatoes are only distantly related to potatoes, they aren’t from the same ‘family’ but that family is part of the same taxonomic order as sweet potatoes, the Solanales. Although the sweet potato is not closely related botanically to the common potato, they have a shared etymology. The first Europeans to taste sweet potatoes were members of Christopher Columbus’ expedition in 1492. Later explorers found many cultivars under an assortment of local names, but the name which stayed was the indigenous Taino name of batata. The Spanish combined this with the Quechua word for potato, papa, to create the word patata for the common potato. The first record of the name “sweet potato” is found in the Oxford English Dictionary, 1775.

The plant is a herbaceous perennial vine. It bears alternate heart-shaped or palmately lobed leaves (sometimes eaten as a green) and medium-sized flowers. The edible tuberous root is long and tapered, with a smooth skin. The colour ranges between yellow, orange, red, brown, purple, and beige. Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato cultivars with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh.

The origin and domestication of sweet potato is thought to be in either Central America or South America. In Central America, sweet potatoes were domesticated at least 5,000 years ago. In South America, Peruvian sweet potato remnants dating as far back as 8000 BC have been found. The sweet potato was grown in Polynesia before western exploration. Sweet potato has been radiocarbon-dated in the Cook Islands to 1000 AD, and current thinking is that it was brought to central Polynesia around 700 AD, possibly by Polynesians who had traveled to South America and back, and spread across Polynesia to Hawaii and New Zealand from there. Sweet potatoes are cultivated throughout tropical and warm temperate regions wherever there is sufficient water to support their growth. Due to a major crop failure, sweet potatoes were introduced to China in about 1594. The growing of sweet potatoes was encouraged by the Governor Chin Hsüeh-tseng (Jin Xuezeng). Sweet potatoes were introduced as a food crop in Japan, and by 1735 was planted in Shogun Tokugawa Yoshimune’s private garden. It was also introduced to Korea in 1764. Sweet potatoes became popular very early in the islands of the Pacific Ocean, spreading from Polynesia to Japan and the Philippines. They are featured in many favorite dishes in Japan, Taiwan, the Philippines, and other island nations. Uganda (the second largest grower after China), Rwanda, and some other African countries also grow a large crop which is an important part of their peoples’ diets. The New World, the original home of the sweet potato, grows less than three percent (3%) of the world’s supply. Europe has only a very small sweet potato production, mainly in Portugal.

The plant does not tolerate frost. It grows best at an average temperature of 24 °C, abundant sunshine and warm nights. Not really suited to the UK. Annual rainfalls of 750–1,000 mm (30–39 in) are considered most suitable, with a minimum of 500 mm (20 in) in the growing season. The crop is sensitive to drought at the tuber initiation stage 50–60 days after planting, and it is not tolerant to water-logging, as it may cause tuber rots and reduce growth of storage roots if aeration is poor.

Unlike normal potatoes, sweet potatoes are grown from ‘slips’. These are the long shoots that have been removed from ‘chitted’ sweet potato tubers. ‘Slips’ don’t have roots, although sometimes there are signs of small roots beginning to appear. The roots will grow once the ‘slip’ has been planted. Whilst it is possible to grow your own ‘slips’ from supermarket sweet potatoes, most supermarket varieties are not sufficiently hardy to grow well in the UK so crops are likely to be disappointing.

When they arrive the ‘Slips’ will look withered, but place them in a glass of water overnight and they will quickly recover. The next day you can plant them up individually into small pots of multi-purpose compost. When planting sweet potato slips, it’s important to cover the whole length of the stem, so that it is covered right up to the base of the leaves. Sweet potato plants are not hardy so you will need to grow them on in warm, frost free conditions for 3 weeks or more until they are established. Warm, humid conditions will quickly encourage the slips to produce roots. They will most likely need to be grown completely inside a greenhouse in the UK climate in large pots filled with good compost and lots of feeding. Sweet potatoes have a vigorous growth habit and long sprawling stems. In the greenhouse it may be useful to train the stems onto strings or trellis to keep them tidier.

Varieties to consider:

‘Georgia Jet’ – considered to be particularly reliable.

‘T65’ – its red skins contrast nicely with the creamy, white flesh.

‘Beauregard Improved’ – a best selling variety, producing smaller tubers with a lovely salmon-orange flesh.

‘O Henry’ – richly flavoured, has a slightly different, bushier habit than other varieties and produces it’s tubers in a cluster which makes for easier harvesting.

Sweet potatoes can be used soon after harvesting, but they will store well for several months if the skins are cured properly. Lay them out in the sun for a few hours immediately after harvesting and then move them to a warm, humid place for 10 days – a greenhouse is ideal. Once the skins have cured they can be stored in cooler conditions provided that they are kept dry. In late summer, approximately 12 to 16 weeks after planting, the foliage and stems start to turn yellow and die back. Now is the time to start harvesting sweet potatoes, although they can be left longer if you prefer larger tubers. If outdoor grown, lift them before the frosts or they will be damaged.

Sweet potatoes are an excellent source of vitamin A (in the form of beta-carotene). They are also a very good source of vitamin C, manganese, copper, pantothenic acid and vitamin B6. Additionally, they are a good source of potassium, dietary fiber, niacin, vitamin B1, vitamin B2 and phosphorus.

Sweet potatoes can replace a normal potato in any recipe, but they do have a slightly sweeter taste so some things might not go with it as much (I can’t quite picture my all-time favourite baked potato and baked beans being quite the same with the sweet potato). I’ve had sweet potato stews that were yummy, curried sweet potato recipes are out there, sweet potato salads, baked and stuffed with humous, tofu, lentils, coronation chicken, ham, bacon, eggs. We’ve seen the sweet potato brownies and muffins and breads (have not tried any of these, I must admit). I like them boiled with greens and cheddar cheese – they go very well with cheese. In fact, the best meal that includes sweet potato that I have had is Cauliflower-Sweet Potato-Cheese. Now that is a good combination. And here is a recipe:

Cauliflower-Sweet Potato-Broccoli-Cheese

(Serves 6) 

  • 1 large cauliflower
  • 1 large sweet potato
  • 1 large broccoli

For the cheese sauce: 

  • 7g butter
  • 1/2-1tbsp plain flour
  • 300g-400g grated cheddar cheese
  • 1/2 pint of milk

[ol]

  • Bring a large pan of water to the boil. Rinse and cut up the cauliflower into pieces. Peel and cut up the sweet potato into small chunks. Put both in the pan of water and reduce the heat to low. Boil for 5 minutes before rinsing and cutting up the broccoli and adding it. Boil for about another 5 minutes or until all the vegetables are cooked.
  • To make the cheese sauce: Put the butter in a saucepan over a high heat to melt. Add the flour, stirring. Take off the heat and stir until combined. Add the milk, a little at a time, stirring. Warm it up over a high flame, stirring. Wait until it bubbles, then turn it down and let it simmer, so it is a thick sauce. Turn of the heat and stir in the cheese a little at a time until dissolved.
  • Turn the grill onto high or the oven to about 180C.
  • In a large ovenproof dish, scrape the drained vegetables into the bottom and scrape the cheese sauce over the top. Scatter extra grated cheddar on top, if you would like to have a crispy topping. Place under the grill or in the oven and cook until it is brown on top (it will be a few minutes under the grill, longer in the oven).
  • Serve hot, with more vegetables like peas or runner beans if you would like.
  • [/ol]

    My other favourite variation is Cauliflower-Potato-Courgette-Broccoli-Cheese. Yum.