The Oca is first thought to have been grown by the Incas in South America but are hugely popular in New Zealand also and are increasing in popularity in this country too with the first farmers taking to growing them commercially recently.They can be used like a small potato and have a slightly citrous flavour. Great raw in salads too!
The leaves can also be eaten as the are related to the Wood Sorrel, they have a kind of sharp lemony taste. But remember the tubers can double in size during the last six weeks in the ground and don't dig them up till the tops have really died back.
How to Grow Oca
Oca need to be started off in pots first to get a good crop due to our shorter growing season. I like to use 15cm (6in) pots or larger. Do this about 6-8 weeks before the last expected frost date as they are frost tender and will suffer badly if frosted. I like to chit mine a little to get them started off, a little like a potato, although they are not related to the potato even though they can be used like a potato.
They do best on a sunny windowsill or conservatory to begin with, on sunny days when the spring air is warm outside I like to put mine out to help harden them off, if this air gets cooler in the afternoon bring them in and don't leave them outside during the night, as cold temperatures will stunt their growth and frosts will kill them off.
I like to use a good quality multi-purpose compost as the growing medium, water regularly but don't over water, they will let you know how they are feeling by their leaves, they start to sag badly when too dry. Try not to let them get too leggy before planting them out.
How to Plant Out Oca
Plant out your Oca when all chance of frosts have gone towards the end of May. They do best in a site where you have been successful with potatoes in the past. As they are not related to the humble potato you can use these a a crop rotational plant.
They develop into quite a bushy plant so give them plenty of room for good tuber production about 90cm(36") between plants. Stems which lay on the earth will put down roots and will develop tubers also adding to your crop. This can be encouraged by softening the soil in these areas and lightly covering the stems but leaving a good amount of foliage on top.
I like to cloche mine for a few days to get them well established after planting out but isn't essential, but protects them from an unexpected late frost should we get one.
How to Harvesting Oca
Tips for Harvesting:
- Oca will be ready to harvest towards the end of November after the first frosts have killed off the tops.
- I usually like to wait till the tops have died nearly completely all back before I dig mine up as I have found the tubers to have swelled further by this time.
- Then dig them up much as you would a potato taking care to find all the tubers otherwise like the humble spud they will grow again next year!
- They will last in the ground, so you can dig them as you need them, but if you have a slug problem these do like to munch on your tubers.
- They store for weeks in the refrigerator.
Where can I get them from?
Purchase or ask a neighbour
Thompson & MorganClick Here
The Real Seed CatalogueClick Here
Ask a neighbour for a couple.You could always ask a neighbour growing them for a couple of tubers then store them in a cool place in a paper bag till needed, they can be chitted just like a seed potato before planting in a pot.
Always keep a few of them back for next year, so they maybe expensive to buy in the first instance they should be a pepetual crop!
How to Cook Oca
Oca can be treated much like potatoes regarding cooking but they need much less cooking time, simply boil, roast or mash!
Just lightly toss them in olive oil or cold pressed rapeseed oil with a few twists of pepper and sea salt and put into a hot oven for around 20 minutes.
Try this maybe!
Stir-fried Chicken with Ham, Leeks and Oca over Steamed Mizuna
- 1lb chicken breast, cubed
- Rape seed oil for stir frying
- ¼ pound ham, cubed
- 1lb Mizuna (rocket if you have no mizuna)
- 2 garlic cloves
- 2 small leeks or 1 large one
- 2 quarter slices of fresh ginger
- ¼ lb Oca
- Sake or water
- 2tbsp dark soy sauce
- Pepper jelly (depending how how you like your food)
How to cook:
- Cube the chicken breast into 2cm cubes
- Slice two small leeks or one large one, crosswise into pieces about 2 inches long, and slice the white part lengthwise.
- Cut about ¼ pound ham into ½-inch cubes
- Rinse about a pound of mizuna.
- Mince two cloves of garlic and two quarter-size slices of ginger.
- Cut ¼ pound oca into approximate ½-inch cubes. (Ocas don’t need peeling, but scrub them with a nail brush (I keep one for kitchen use only! to make sure no gritty soil is on them.)
- In a wok with a little rapeseed oil add stir fry the chicken till golden in colour and cooked through
- Add the leeks and stir-fry breifly.
- Add the garlic and ginger and toss, set aside.
- Add the Oca to the wok and stir-fry briefly.
- Add two tablespoon of water or Sake (Rice Wine) if you have it, reduce heat and cover wok.
- Cook Oca until they are just tender as you like and put them in the bowl with the leeks and chicken.
- Add more oil if needed and briefly stir-fry the ham.
- Add the pepper jelly to taste, and sake if using water if not to the wok to make a sauce, you need enough to make the final meal well coated but not completely imersed.
- Add the chicken and leeks mixture and coat in the sauce adding a little roasted sesame oil for flavour and toss a few times.
- Steam the Mizuna in the wok just until the greens have wilted.
- Spread the mizuna in a serving bowl or on a platter, and put the reserved chicken, ham, and vegetables on top.
- Serve the dish with steamed rice.