For my Masters dissertation last year I did some research into gardeners who choose to grow unusual edible crops. I settled on two species to investigate, achocha and oca. In the past I’ve written about how to grow achocha – it’s a nice, easy plant and in a temperate climate you should have no problems getting a significant yield. You may have more of a problem dealing with the glut….
Oca (Oxalis tuberosa ) isn’t quite as simple. It’s increasingly easy to get hold of tubers in the UK, with them being marketed as very similar to potatoes – but without the risk of your plants being devastated by blight. But my research showed that many of the people who do try oca find their yields to be very disappointing. So how do you grow oca for the best results?
In its homeland, the Andes, oca is known only as a cultivated plant; it’s closest wild relative is still a bit of a mystery. There are lots of different varieties planted there; they come in different colours, and they’re used for different purposes*. Some have been bred to be eaten raw, some are best when cooked and still others are bitter and have to be processed into a dried starch product before they can be consumed. Some varieties are used more like a fruit than a vegetable. Oca is quite popular in New Zealand, where it’s known as the ‘New Zealand Yam’. Here in the UK you’re likely to have a choice of perhaps three or four varieties, sold by their colour. Who knows what they might have been used for traditionally? We’re not off to a flying start.
The problem is that this species is sensitive to day length. In the UK they only begin to produce tubers when the days begin to get shorter, and they’re frost sensitive. Selecting varieties that might crop here at all is a problem,
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