Herb: Oca

Latin name: Oxalis tuberosa

Synonyms: Oxalis crenata

Family: Oxalidaceae (Wood Sorrel Family)

Edible parts of Oca:

Tubers - raw or cooked. An acid lemon flavour when first harvested, if left out in the sun the tubers turn sweet, so sweet in some varieties that they are said to resemble dried figs and are sold as fruits in local markets in S. America. The cooked root is delicious whether in its sweet or acid state, it can be boiled, baked etc in similar ways to potatoes. The tubers tend to be rather smaller than potatoes, with good sized specimens reaching 8cm or more in length. The slightly waxy skin makes cleaning them very easy. They contain about 70 - 80% moisture, 11 - 22% carbohydrate, 1% fat, 1% fibre and 1% ash. The carbohydrate is rich in sugar and easy to digest. Acid types are rich in oxalic acid (up to 500ppm) but sweet forms have much less oxalic acid than is found in potatoes. Edible young leaves and flowers - raw or cooked. Poor quality. Use in moderation, see notes at top of sheet,

Description of the plant:


45 cm
(1 foot)

July to

Habitat of the herb:

Unknown in a truly wild situation, though plants have been found growing at heights up to 4000 metres in the Andes.

Propagation of Oca:

Seed - best sown as soon as it is ripe in a cold frame. Prick out the seedlings into individual pots when they are large enough to handle and plant them out in late spring or early summer. Seed is not usually produced in Britain. Harvest the tubers in late autumn after the frosts have killed off top growth. Store in a cool dry frost free place and plant out in April. Basal cuttings in spring. Harvest the shoots with plenty of underground stem when they are about 8 - 10cm above the ground. Pot them up into individual pots and keep them in light shade in a cold frame or greenhouse until they are rooting well. Plant them out in the summer.

Cultivation of the herb:

Unknown in a truly wild situation, though plants have been found growing at heights up to 4000 metres in the Andes.

Medicinal use of Oca:

None known

Known hazards of Oxalis tuberosa:

The leaves contain oxalic acid, which gives them their sharp flavour. Perfectly all right in small quantities, the leaves should not be eaten in large amounts since oxalic acid can bind up the body's supply of calcium leading to nutritional deficiency. The quantity of oxalic acid will be reduced if the leaves are cooked. People with a tendency to rheumatism, arthritis, gout, kidney stones or hyperacidity should take especial caution if including this plant in their diet since it can aggravate their condition.

Plant information taken from the Plants For A Future.