Growing Oca (3) – and harvesting and eating it

There continues to be lots of interest on this blog in growing oca and I have been waiting to harvest my oca before putting on an update.  Oca tubers begin to form after the autumn equinox towards the end of September as the days grow shorter and the nights longer.  The top growth is killed by frosts but tubers continue to form for a few weeks after this point and I dug mine too early last year not taking advantage of the additional time for them to develop.  So this year I resolved to wait a full three weeks after the top growth died before harvesting any tubers.   However this autumn and the early part of the winter has been unseasonably warm, in contrast to last years sub zero temperatures from the end of November through to January.  This autumn / winter the garden does not know where it’s at and all sorts of things are growing or flowering when they would not normally be.  Yesterday I found a daffodil in flower hiding beside a Daubenton’s kale.

Anyway we have now had some light frosts; not enough to give one of those archetypal winter wonderland mornings but sufficient at least to kill the top growth of (most but not all) ocas.  Last summer was my second year of oca growing and I saved tubers and was able to plant more than the first year.  The saved tubers were a white variety and I bought a red variety as well.  Even giving some away I had more than I could reasonably manage to accommodate in the garden so some found themselves in places that were not planned.  I put the biggest into the prime spots and the smaller ones into other places and it is these that I have harvested first.

As well as planting some in the main polyculture beds others have gone into what was a flower bed and some into bags and a pot.  Whilst I do not have a great deal of room for growing in I am aware that some people do not have any actual garden and must use containers.  Therefore I have tried a number of perennials in containers and particularly wanted to try growing in bags as they are potentially easier to move about than pots.  I did not want to buy any custom made and expensive ones and used one large and one medium supermarket heavy duty shopping bags, each lined with a black sack with drainage holes in the bottom of the black sack but not the outer bag.  I used a good quality organic potting compost and the results in top growth were astounding.  I think that the plants responded particularly well to the depth of soil that was available to them in these bags.

This is the oca in the large bag planted also planted with some Cherokee Trail of Tears beans.  It is exuberantly lurching and spreading out of the bag in a fountain of growth.  The oca grown in containers were (of necessity) watered and fed, but those in the rest of the garden were only watered on very rare occasions if they looked wilted and unhappy.  We had a ridiculously dry summer last year and I am sure they would have appreciated more water but I am trying to find out what happens when nature is allowed to take its own course (as much as is practical).

When I harvest these and any other root crop I am very mindful to disturb the soil as little as possible.  Any disruption to soil kills untold numbers of beneficial organisms and as I really want a healthy soil and healthy garden I have no wish to do harm.  Therefore I do not dig as such to get the oca out, but rather explore with the end of a garden fork and a small trowel, pulling at the remaining top growth to liberate the plant and attached tubers, trying to make as little disruption as possible.  Afterwards I mulched the whole area with several inches of home made compost.  The plants harvested to date have yielded the following:

  • 682 g white oca from two plants in the medium sized supermarket bag
  • 182 g white oca from one plant in an unprepared (flower) bed with little attention bar some mulching during the summer
  • 185 g from one plant under the same conditions as above
  • 127 g from one red tuber under the same conditions
  • 154 from another red tuber as above
  • 97 g – unclear which plants they emanated from

This gives a total of 1427 g from 6 or so plants.  The white oca tubers seem to yield more than the red and the plants in the bag produced more and larger tubers than those in the polyculture patch.  I suspect this was because they had rather more favourable conditions.  It will be interesting to see what yields are obtained from plants grown in other beds and containers.

The plates below show the haul!  Red oca on one plate, on the left are the larger tubers from the bag and the right the smaller ones from the polyculture bed.

Some of the tubers were a little nibbled and one or two were bad inside, but most were very healthy.  Some of them came out as little more than slightly swollen stems and I have held on to these with the tiny ones and any that had turned green as part of the stock to replant next year.

Some of the remaining stems had tiny baby tubers beginning to form above ground and I have made a mental note to use plenty of mulch next year to build up round the plants, akin to the way potatoes are earthed up to see if that can help prevent getting greened tubers and maybe encourage the plants to produce more.

We have just eaten some of the oca tubers in curry, this is the recipe that my partner just invented and very nice it was too:

  • spice mix made from one clove garlic, 1 teaspoon coriander seed, 1 teaspoon cumin seed, a dash of ready prepared chilli in a jar, 1 teaspoon grated fresh ginger root, 1 stick lemon grass, 1/2 teaspoon grated fresh nutmeg, 1/2 teaspoon cinnamon, 4 cloves
  • this collection was mixed and mashed up together and gently fried with two chopped onions in a minimum of olive oil
  • to this was added a tin of tomatoes and a few spare fresh tomatoes and a little stock and left to simmer whilst
  • 500 g of oca was cleaned, cut into bite sized chunks and par boiled for 10 minutes
  • the oca was added to the tomato / spice mix together with a handful of fresh coriander leaf and about 150 g baby spinach leaves and then left to cook for another twenty minutes or so.
  • Next time a little lime juice is going to be added and also some squash.

About Anni Kelsey

I love forest gardens and forest gardening, nature, reading and everything good about being alive. I have written two books - the garden of equal delights (2020) - about the principles and practice of forest gardening; and Edible Perennial Gardening (2014) - about growing perennial vegetables in polycultures, which is basically forest gardening concentrating on the lower layers.
This entry was posted in Forest Gardening, Permaculture, Polycultures, roots and tubers, Telford Garden and tagged , , , , . Bookmark the permalink.

17 Responses to Growing Oca (3) – and harvesting and eating it

  1. Pingback: 6 Unusual Vegetables You May Not Have Seen Growing BeforeGreenside Up

  2. Bill says:

    Although planting the small tubers will produce plants, the first rule of saving seeds, tubers, etc is to save the ones that are bigger or taste better. That is of course why we have different varieties of any plants we grow. Plant the biggest and tastiest, eat the rest!


    • brambonius says:

      That rule only works if you have genetically diverse crop, which happens when you work with seed, but not with tubers. All tubers from one plant, and all descendants from that tuber unless it seeds will be clones, so taking the smallest or the biggest doesn’t matter.


      • annisveggies says:

        Thanks for that information. I was meaning to get round to replying to Bill, which was just to say that I saved lots of small tubers and gave as many away as I could which I hope was a good use of them!


  3. Adam says:

    Did I see that you have some spare oca tubers?
    I would love to try growing some this year.
    Best Wishes


    • annisveggies says:

      Hi Adam
      I’m sorry I missed your comment and question back in February. I did have some spare tubers but have given them away now. However I do have some planted that have not yet come up and would be send-able in the post. If you would like some please email me on annisveggies at hotmail dot co dot uk.


  4. David Bell says:

    Hi i grew oca for the first time this year I tried various colours but the deep red were the best tasting I grew them in potato bags and they were very succesful I tried them directly into the garden but these were poor would not grow them in garden again


  5. Pingback: Oca tubers being shared by Anni « Southend-on-Sea in Transition

  6. Hi Annie
    I have had no access to the internet recently so I havent been able to keep up with the progress of your oca. I hope all went well this year and you got a bumper harvest. You must have harvested them by now as the weather has been awful these past few days with the heavy frosts we have had.
    After harvesting mine I am kicking myself because the actual plants were still quite green under the frosted tops. I could have probably waited another 3 weeks before digging the plants up. I wont be making that mistake again next year.
    We have to learn by our mistakes but I guess I have learnt the hard way.
    Anyway Annie good luck


  7. annisveggies says:

    Hi Gaynor
    Good luck with the site preparation! I don’t know about whether or not oca grow better in shade but I am testing it out with some that have been growing in shady sites in my garden. However I haven’t harvested them yet. It won’t be in any way scientific but may give me some idea.
    I will certainly be able to spare some tubers. If you email me your postal address (annisveggies at hotmail dot co dot uk) and let me know how much space you have that you want to plant with oca I will send you some. I am sure I will have enough to spare unless you want to plant acres!


  8. annisveggies says:

    Hello Gaynor
    I think it is probably a good idea to earth them up like potatoes. I am going to do that as I noticed them starting to make baby tubers along the stems close to the ground and it seems logical that if they are earthed up this will give them more soil space to make tubers in.
    I would definitely plant the tiny tubers you have harvested if for no other reason that it’s better than throwing them away and they don’t sound big enough to eat. If you would like some others to try for comparison I can send you some as I have more than I can re-plant. I did the same as you last year and the year before – planted in pots indoors (garage) at the end of February and then moved outside when the foliage was up but brought them under cover at night till frosts were done with at which point they were planted outside. I would try to give them the longest possible growing season with as much fertility as possible and adequate / ample water.
    I don’t know about manure as I don’t use it but I do try to make my garden as fertile as I can using home compost and lots of mulch (for example see post – I am pretty convinced that fertility and depth of soil are very important in determining yields.
    All the best


    • gaynor says:

      Hi Anni,
      Thanks for your reply and useful help. I will definitely plant the small tubers if they survive the storage through the winter. I hope they do then I can let you know how they performed. I will also earth them up this year because it does make sense as they were growing up the stem. I am furious with myself because I think I was a little quick off the mark to harvest them as we have had a really mild autumn and winter so far, I could have probably left them another couple of weeks. Anni I would love a few tubers if you have any spare. I have read that they prefer to be in a shady position rather than full sun is that true do you know.
      I am going to prepare a site for them today for the best start they can get whenits ready for them to be planted outside. I will add my garden compost and maybe a little manure and give that time to completely rot down in time for there planting.
      Thank you Annie for your help and what a great site.


  9. annisveggies says:

    Hello Gaynor – that must have been so disappointing for you, especially as the plants themselves grew so big. I have been fortunate with mine I guess, but have just had a look at the excellent blog specifically about growing oca which gives top tips for good yields at this web page:

    In my area (Shropshire) we had a dry summer last year and I think this reduced yields. Point four in the list of tips is about maintaining moisture levels from late summer to autumn as the plants then have a lot of foliage. Did you have a dry spell or period at all?

    I hope you have more success this coming year.


    • gaynor says:

      Hi thanks for ur response I will try again this year and maybe earth them up like potatoes, do you think I will be able to plant the tiny tubers and would they produce a crop also do they like manured ground.


  10. gaynor says:

    I grew oca for the first time this year and I was very disappointed. The plants grew huge and then was killed off by the frost. I left them until 5th January to harvest and what tubers I have are smaller than a pea. I had found most of them on the stems and not the roots. The roots were poor and very small (hardly any there) I dont know how they supported such big plants. I planted 12 tubers in individual pots in spring and planted them out once the fros had disappeared. I had probably 2 tubers on these plants that were about an inch long and all the rest were very very small. Does anyone know if I can plant these next year and will I get a crop from a tiny tuber. The tubers I used last year were probably about half to 3/4″ big. I think I really need help and any advise would be welcome.


  11. Pingback: Growing Oca (3) – and harvesting and eating it | Anni's perennial … – Growing Green Beans

  12. Mrs A. Eggleton says:

    I have ordered my own oca this winter and am really looking forward to trying them out! Is there in fact a problem with green oca tubers? Isn’t this just chlorophyll, as in green-topped carrots? The poisonous part of green potatoes is the solanin, which develops along with the chlorophyll in the light. But I may be wrong.


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