Now here's quite an unusual plant that most of you have never heard of probably, but I think is really worth mentioning, at least to people who are interested in growing veg. Oca is a plant that produces underground tubers, just like potatoes, but it's an incredibly vigorous and resilient plant that isn't really bothered by pests or diseases, unlike potatoes which are often affected. The plant grows similarly to potatoes and the Incas apparently used to grow both crops next to each other, as staple crops for their annual diet. Just like potatoes, Oca stores exceptionally well. But Oca is a far later crop than potatoes, often only ready in late November or early December, depending on local conditions. And Oca are not too fond of early frosts, they need the dark light levels of late autumn to produce their tubers and the longer you wait the fatter your Oca gets. You should really harvest them 1-2 weeks after the first frosts have hit the plants. It's quite extraordinary really, when the first frost hits the plant the lush green foliage of the plants starts wilting and dying down immediately. That's when the remaining energy of the plant
is used to fatten the Oca.
As you can see on the picture to the left, Oca plants form very effective ground cover. The picture was taken at Helen's Bay Community Garden, and the three tires in front of the raised beds contain Oca plants. The tire on the left shows an Oca plant in its early stages and the other two are in intermediate stages. The plant produces a lot of foliage over its lifetime and produces many small flowers. It's really a non-fuss plant to grow and it stays happy during its entire cycle. Oca tubers are normally chitted like potatoes before planting, meaning that the tubers are taken out of their dark storage in March/April and put into daylight so that new growing buds can form well. Oca Tubers should be planted at the latest in April because the plants profit from a long growing season, and if you want to use the plants as ground cover in especially weedy patches of your garden or allotment then it makes sense to get them in the ground as soon as possible.
And this what the actual thing looks like when uprooted. The variety we planted this year are scarlet and white and when pulled out of the ground are incredibly dark red, or scarlet. As with potatoes, it's incredibly satisfying to dig up Oca, it's like finding hidden treasure in the ground. It really gets you excited like a kid, and our harvest was quite plentiful so there are plenty of tubers to dig up when grown properly. What's also unusual with Oca is that unlike potatoes, they can be eaten raw. Actually it seems that the whole plant is edible and in the Andes the tender leaves and young shoots of the plant are eaten as greens. And what makes them so nice I find is their timing. Because potatoes are a summer/autumn crop depending on your variety and where you live, I love the fact that Oca is harvested in late autumn and early winter. That's probably a reason why they were so important in the Inca crop rotation. And even though Oca can be very much prepared and cooked like potatoes, they really shouldn't be used as a replacement to potatoes. They are two completely different crops, and actually they are very nice combined in a dish, such as a gratin.
They do become quite pale though when cooked and lose much of their brilliant colour. Below on the left you can see an Oca tuber when sliced in half, and as you can tell they are not incredibly huge. Now they won't grow that much bigger than that and so are not like spuds which can get absolutely ginormous! So Oca tubers stay quite small, and when cooked have a very interesting taste and consistency. They are very creamy, like a mash almost, or a combination between a potato mash and a radish puree. And the taste when cooked goes into the direction of potato, but steers off slightly through its tangy, almost sorrel like flavour. This tangy or slightly sour flavour is also present when eaten raw. I vividly remember the first Oca I tasted, and it was quite different. They do taste slightly odd at first, especially when tasted unadulterated. They are really a combination of flavours, of known flavours, but also slightly unknown. You can't really put your thumb on it. Indeed most people give slightly different descriptions of the flavour. Oca is very crunchy raw, just like a nice crisp radish, and the first flavours are almost opposing. There is that sweetness which comes from the colourful middle, that almost tastes like fruit or strawberries in my opinion (most people differ on what fruit it's supposed to be). But simoltaneously there is a savoury flavour, almost salty in a way, but not really. A deep savoury flavour is the best I can describe it as. And then there is the tangy or sorrel like aftertaste. All in all this may not sound appealing, but it's well worth trying as it is one of the more unusual taste experiences you will have in your life!
But this oddness of flavour is transformed into refreshing crunch and delicate flavour when Oca is used in a salad or is dressed nicely in whatever way you fancy. A bit of acidity and some nice oil, and also a bit of spice, gives the humble Oca a fancy makeover and thus becomes a welcome change to the usual winter diet of hearty stews and roasted vegetables. That is really one of the reasons why I welcome Oca so much, because it is so crunchy and refreshing at that time of the year and lends itself perfectly to salads. It's also a very healthy vegetable when cooked raw as it is an important source of vitamin C, potassium and iron. So no wonder that Oca is still a crop that many subsistance farmers in the Andes rely on.
Although this account of the humble Oca has been quite long and in full detail, I think it is well deserved because it is such an unusual food, very interesting in flavour both cooked and raw, very attractive looking indeed, very healthy to eat too and a joy to grow in the garden! What more could you want?! And the festive colour of the Oca also works for Christmas...perhaps at some point it will become the new seasonal food. Forget pomegranate, forget brussel sprouts, just eat Oca!
If you want to know where to get hold of Oca tubers for planting then the realseed catalogue is the place to go! They also offer more information on planting etc.
