Magic Oca Tubers

At the back end of 2020 I purchased some oca tubers.

Oca is a South American tuber crop. They look a bit like small potatoes, but they are in a totally different family. Whereas potatoes are in the same family as tomatoes (hence the susceptibility of both to blight), oca grow like an oxalis.

I'm not going to pretend oca is a perfect crop to grow. Firstly the tubers are stupidly overpriced, often around £1 each for tubers an inch round if you're lucky. Who is going to eat something worth that much? No, I'd rather grow them on and sell them for 50p each! But come the day when I end up with too many to sell and everybody else has had the same idea, then I will start to treat them more as a crop to be eaten.

Those first tubers I purchased could not have been more of a disappointment. They had been either harvested too late or not stored frost-free after harvesting, causing at least half of them to just wither and rot away. The rest I tried to store over winter but by the spring they were just empty shells of decomposing skins.

And therein lies one problem with oca. It doesn't form tubers until late in the year but they do not survive a heavy frost, so it's a tuber on the edge of its range. But as with wild birds, insects and plants, that range is creeping ever further north as our climate changes.
In fact it is this climate change which drives the need to rethink some of our crops. It's an unusual year now when my potatoes aren't hit by blight due to our warm, wet summers.

Anyway, back to the point. Not to be put off, I found some reasonably priced oca tubers on ebay. I am still experimenting with how to store such tubers overwinter. Since oca are so small, I don't want them drying out. My standard storage for potatoes is in a wardrobe in the garage. This keeps them cool and dark without exposing them to frost. The wardrobe offers protection from rodents too. I just store my potatoes in thick paper bags. I decided to store the oca in a mix of coir, perlite and sharp sand. For an insurance policy, I also stored some in a tub of peat-free compost in the fridge. I occasionally had a rummage around during the winter just to check their progress - all was fine.

I don't want to wait till May, when we are frost-free, to start my oca tubers growing, so instead my plan was to pot them up indoors to give them a head start. Besides, it would be difficult to stop them sprouting of their own accord if I waited too long into the spring.

So in mid-March I released my stored tubers from their hibernation. They had all stored really well. No softening of the tubers and no rot. The ones in the fridge were more ready to go, probably because there is more humidity in there, even if the temperature is more controlled.

What amazes me about tubers is how such a tiny, insignificant ball of plant material can throw up so much growth and replicate itself so efficiently over a year. Just take a look at the emergent growth from these tiny little tubers!

Coming up for mid-April now and oca plants seem really strong. A couple have shot away but most are throwing up really strong young shoots. They are in an unheated conservatory so that I can check their growth until they can go into the ground outside. That way we get sturdy plants.

The original plan was to grow the oca in with the perennials on the edge of the forest garden. However, the soil is still a bit too clayey in there which makes for difficult harvesting. So instead they are going into some of the conventional vegetable beds - these are more and more becoming a mix of annual crops and perennials anyway. 

Hopefully by November I'll be pulling handfuls out of the ground a bit like this hill farmer I witnessed harvesting his Oca recently in Mexico.

Maybe I'll even have enough to eat a small plate full.

I'll keep you updated.