Sweet potato 
Versatile and becoming increasingly popular, sweet potatoes are well worth trying outdoors in milder areas - or in a glasshouse or polytunnel elsewhere. Even in mild regions, indoor growing will produce more reliable crops.
Planting
Plants are best grown from cuttings or slips ordered from a mail order supplier.
You can try growing them from shop-bought tubers, but you can't plant them like ordinary potatoes as they don't grow in the same way. Many shop-bought tubers are also treated with an anti-sprouting agent, so give them a good scrub to clean them first.
Then place in moist sand in a hot propagator or even in the airing cupboard. Once the sprouts/shoots are 5-7.5cm (2-3in) long, they can be removed as cuttings and potted up into small pots of cuttings compost and placed in a warm propagator to root.
Growing
For full details on growing sweet potatoes view our advice profile.
Harvesting
Tubers take from four to five months to mature. They can be lifted from the end of August, but it is usually better to leave them until the leaves begin to yellow and die back.
