Also know as the 'New Zealand Yam', Oca tuberosa originates from the Andes in SouthAmerica, where it has been cultivated since the time of the Inca's.
This easy to grow plant produces small to medium sized tubers with a 'lemony' taste. With clover like foliage and pretty yellow flowers it is equally at home in a flower border as well as the vegetable garden.
Oca grows well in light well drained soils, with a pH range between 5.3 - 7.8.
Seed tubers can be planted directly into prepared beds, alternatively pot the seed tubers up and plant later in the season to avoid late frosts.
At about 4 months the Oca plants should be hilled/ridged like potatoes, this will encourage tuber formation and increase yield.
Oca do not start to form tubers until daylight hours shorten. In the UK this is around mid to late September. At this time it is also important to protect the plants from frost until at least late November.
Lift the tubers when the top growth has been frosted and died back. Wash the soil from tubers immediately and leave to dry. Oca are high in oxalic acid, leaving the tubers on a window sill for a week will convert the organic acid and increase the sweet taste. Then store in a cool dark place.
Oca is one of the highest vegetable sources of carbohydrate and energy. A good source of pro-vitamin A (beta carotene), and also contain potassium, vitamin B6 and small amounts of fibre.
The tubers taste good roasted or boiled and can be added to stews and soups. In Mexico Oca is eaten raw with salt, lemon, and hot pepper.