Oca

Oca – oxalis tuberosa potato like tubers with a lemony flavour appearing in the leaves aswell making them great in a salad. This comes from the oxalic acid. Enormously popular in parts of South America where it has been grown for centuries. It has also been grown in parts of New Zealand (where it is known as the New Zealand yam) for 150 years or so.

They have a rather complex flavour – lemony and sharp when first dug (due to the oxalic acid) which eases off after a few days in the light. They won’t turn green like potatoes though, as they don’t contain the troublesome chemical solanine. Equally importantly, they aren’t susceptible to blight and seem to be less attractive to slugs.

You can eat them raw – they’re crunchy like a carrot – Our favourite is roasted for 25-30minutes (no need to peel them) and they develop a creamy texture like a new potato with its own distinctive flavour, if skins are caramelised they take on a delicious sweet crunch

If ordering tubers during autumn/early winter: Keep them in some slightly damp compost somewhere cool and dark. Plant into pots at the beginning of of March and leave to grow on somewhere light and frost-free (if they are sprouting very early you can hold this back by putting somewhere cool and light)

Plant them out when no longer any danger of frosts. The spot you plant them in should be sunny, well-drained but moisture retentive, crops a largely improved if some manure is added. space them around  30-60 cm apart.

They may grow quite slowly at first but don’t be alarmed by this. The foliage may also fall over when the stems are long but again don’t be alarmed.

The tubers swell as temperatures and light decreases so don’t dig too early. Wait until frosts have killed off the foliage but dig up (or protect the soil if you can’t get to them straight away) before any risk of the soil freezing as this will destroy the tubers. Generally untroubled by pests and diseases.

They bulk up well, so keep a few tubers back to sow the following year.