Yams 

Small tubers can be planted outside at the end of May after the fear of frost. For better and more reliable results the tubers are best planted up in pots of compost indoors and planted out at the end of spring when they have produced some growth.

Yams also form tubercles (small tubers) in late summer and early autumn in the leaf axils. These are a good way of propagating plants and make excellent planting material. Harvest them before they fall from the plant and store them in a cool, but frost-free place over the winter. Make sure they do not dry out. Pot them up into individual pots in early spring and plant them out when in actively groing in late spring or early summer.

Plants need a fertile well-drained soil. They prefer a position in full sun, although they will also succeed in light shade.

Yams produce long, vertical roots so it is possible to grow plants quite close together, spacing them 25-30cm (10-12in) apart.

Keep plants well watered and feed regularly with a balanced liquid fertiliser throughout the growing period.

Harvest the tubers in autumn, once the plants start to die down. Growing from tubercles produces smaller tubers, which are much easier to lift; those grown from tubers can need deep digging to harvest them.