Sweet potatoes (Ipomoea batatas) are the tuberous roots of vining plants. They belong to the same family as Morning Glories (Ipomoea tricolour) and you’ll easily see the similarity in their leaves to the sweet potato vines.
Sweet Potatoes have grown in popularity in recently, and are widely grown in warmer climates. You can plant hardier varieties outdoor in the UK if planted in a sheltered position. Varieties such as Georgia Jet and T65 are reliable in the UK but you may opt for smaller, bushier varieties such as Bush Porto Rico for your garden as you will need a lot of space.
Sweet potatoes are best grown from unrooted cuttings, called slips, which can be bought from April onwards. You can make your own slips by filling a bucket halfway with damp sand, and then half burying several sweet potatoes sprouty side up. Alternatively sewer with a wooden stick half way through the potato and place over a jar of water, the bottom hal;f submerged. Keep in a warm place and within six weeks you will have many slips to select. It is best to grow from seed tubers, rather than edible supermarket tubers.
Sweet potatoes like free draining, slightly acidic soil and a sunny, sheltered position. Dig over the soil in late March/April, add in plenty of organic matter and cover with black polythene to suppress weeds and warm the soil. Plant in raised rows 15 cm above the ground, spaced 30-45 cm apart, leaving 1 metre between rows.
Plant out your potatoes in late May/early June when the ground starts to warm up and the risk of frosts has passed. Harden off your potatoes by placing them in slits through the polyethylene. Sweet potatoes like the warmth so cover the potatoes with a cloche or fleece.
Keep your sweet potatoes weed free until the vines form a natural mulch.. Do not feed as this will just produce foliage. Water as necessary to ensure good growth but to avoid the tubers from splitting do not water 3-4 weeks prior to harvest.
You can also grow sweet potatoes inside glasshouses in containers or grow bags. They crop best at temperatures between 21-26 C. Plant up slips into small pots of multi purpose compost and transplant from this pot once they have produced plenty of roots. Tie in foliage to cane or similar. Water well and feed fortnightly with a high potassium liquid feed.
Sweet potatoes will be ready to harvest in 4-5 months. Lift the tubers when the leaves turn yellow and die back. The tubers grow close to the top of the soil so be careful when harvesting as they can bruise easily. They are hard to store so it is best to eat them quickly..
Plants can be overwintered in greenhouse or on windowsill.
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