Guest blogger Phillippa Lambert writes about growing Oca – a versatile and tasty vegetable.

Oca

A new vegetable crop for me this year is Oca (Oxalis tuberosa), along with Yacon, (a treat for next growing season), Oca is one of the ‘lost crops’ of the Incas, and a staple crop in Bolivia and Peru.  It is grown from tubers, much like potatoes, but is not related to them in any way, hence they are blissfully free from blight. Oca produces attractive yellow flowers set against prolific trefoil foliage, that acts as effective, and largely pest-free, ground cover. The only drawback is that Oca is tender (preferably started under cover in the spring), and needs a moderately long growing season to achieve a worthwhile crop.

Oca can be cooked like new potatoes (very tasty with a lemony tang), roasted in the oven, or even used raw in salads in much the same way that radish is prepared.

Oca roasted in olive oil and balsamic vinegar, with red onions and beetroot, dressed with soured cream

Oca and watercress salad

I started off my Oca in the spring from small chitted tubers, in the greenhouse in Root trainers.  As soon as the weather warmed up enough (early May on the Isle of Wight), I set them out in rows, 12″ between plants, and about 30″ between rows.  They require very little work during the growing season apart from keeping down any weeds before the foliage closes over, and some earthing up to increase crop yields.  An absolutely crucial piece of information is that Oca does not start to form its tubers until the days shorten in the autumn — it is day length dependent.  The key to a heavy crop is to keep the leaves protected from frost as long as possible — fleece may be necessary if early frost threatens — and only dig the crop about 2 weeks after the top growth has been completely killed by frost.

Oca, fleece-covered in late November, to preserve the top growth as long as possible

Storage is easy;  as Oca does not react to the light by going green, as potatoes do, simply sort the crop — the larger tubers for eating, smaller sizes for next spring’s seed, and place in paper bags in a consistently cool place.  Refrigeration is not necessary. Those for planting can be chitted in a frost-free, light position in early spring, (just like potatoes), and the whole cycle starts again!

Lifting the crop just before Christmas

Lifting the crop just before Christmas

Washing off the tubers before storing

Washing off the tubers before storing

A selection of both colours

A selection of both colours

Read more about Phillippa Lambert at www.lakehousedesign.co.uk

Phillippa Lambert

Phillippa Lambert is a landscape designer based on the Isle of Wight at a unique site in the Undercliff of the Island — a favoured microclimate sheltered by enormous south facing cliffs. In 2002 Phillippa and Stephen Lambert came across the ‘lost’ gardens of a Victorian mansion dating back to the 1820s, managed to acquire part of the site, including the walled garden and ornamental lake, and have since worked on their restoration. The result is not an ‘expert’ garden and does not try for technical perfection in any sense. ‘Make do and mend’ is the keynote — most plants being raised from seed or cuttings— and self-sufficiency is the motivation for all the growing in the walled garden. In essence, this site goes back to the philosophy of ancient gardens in sustaining the body as well as the soul. Read more at Lakehouse Design.