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Grow your ownUrban Farming

Oca Giggles!

24 January 2022
oca harvest from outdoor plant (December 2020)
oca harvest from outdoor plant

You could easily think I’m insane starting a blog about plants in winter.  It’s usually not the best season for plants and probably not one that you associate with harvesting.  But this week, I’ve been celebrating my oca harvest!

Oca origins

You may not have heard about oca – it’s a native of the Andes in South America.  I first heard about them in 2020 and was lucky to get little plants delivered in May.  Unfortunately these poor little critters got posted during a weekend in a heatwave and only three survived.  You may wonder at the title of this post (has anyone heard an oca giggle?) but that’s the variety of the plants I ordered.

oca plantlets potted up on arrival - all in poor health after being posted during a heat wave weekend 11/05/20
6 oca plantlets potted up on arrival

Growing Conditions

I wasn’t sure what conditions the plants would prefer – they come from closer to the equator (hot) but up in the mountains (cold).  Hedging my bets, I put one on a sunny shelf in the greenhouse, one shaded on the floor of the greenhouse and another outdoors.  This being the spring of lockdown, I couldn’t get more pots after I ran out, so 2 of these were in compost bags with the bottoms pierced for drainage!  The plant on the shady greenhouse floor obviously wanted more light as it went sprawling across the path to find it.

oca growing in shady part of greenhouse - sprawling to get more light 18/10/20
oca growing in shady part of greenhouse

The plant on the sunny greenhouse shelf went a particularly pretty pink colour, while the others stayed green.  All of the plants had the lovely oxalis leaf shape and the plant was pretty enough it didn’t need to be hidden away.

oca growing on sunny shelf in greenhouse - turning pink 18/10/20
oca growing on sunny shelf in greenhouse – turning pink
oca growing outdoors 18/10/20
oca growing outdoors

The tubers only start to form when the day length reduces past 9 hrs/day, so the plants like long autumns. Like several winter harvesting plants, the tubers are not ready until after the visible plant dies back – some claim the taste is better after the first frosts.


As winter arrived, all the plants died back and December frost signalled the first harvest in 2020!  I only harvested one plant (hoping I would get new plants from the undisturbed oca in the summer).  I rummaged in the pot and pulled out the bigger tubers (201g in total).  This year (2021) I had to wait until January 2022 for frost, but further north you would have been able to harvest earlier.  This time, there was 259g from the same pot – maybe I was a bit more thorough searching for the tubers!  There was also 146g from a smaller container – ok I admit it – the plant was still in a compost bag from last year!  

I’ve read the crop can be increased by earthing up the plants – that’ll be worth trying next year as at the moment, they’re in relatively shallow earth (11cm deep).  Another view on this is that earthing up will cause more tubers, but they’ll be smaller – I’ll let you know what I find when I try it.

Some of the tubers I’ve harvested have been nibbled. Funnily enough – the plant in the reused compost bag had less damage than the one in the pukka pot! I’m not sure who the culprit was but I don’t think it was slugs (or I wouldn’t have had a crop left!) Next year I’m going to be brave and try oca in the vegetable plot where I often have a problem with slugs – we’ll see how well they cope!  

oca harvest from outdoor plant (December 2020)
oca harvest from outdoor plant (2020)

Space efficiency / Value for money

One of the things I’ll be doing in this blog is considering space efficiency and value for money.  After all – when we’ve limited space we want to make the best use of it we can!   I’ll be considering the time the plant takes to grow, the space taken up by the plant and the size of the harvest.  Then I’ll be relating that data to the space required to provide a year’s worth of calories (2000 cal/day) and protein (50g/day) for an adult.  As a perennial plant, oca will be in the ground for 365 days each year.

20200.1980.110.201 0.002781 ~23972247
20210.1980.110.259 0.003584 ~18601744
20210.0490.150.146 0.008149 ~ 818 767
Oca Yield (*space required to supply annual nutrition for 1 adult)

Looking beyond calories and protein, oca is considered a good source of Vitamin C and Iron; however, they are probably best avoided by anyone on a low oxalic acid diet. The stems and leaves can be eaten; although I haven’t actually tried yet as I didn’t want to weaken the plants in summer.

From the results in the table, it seems that the reused compost bag has been very successful! It had a much better yield for the soil area. The tubers were bigger and less nibbled too!

Value for money is hard to calculate as I don’t think you’re going to find these in a supermarket (maybe a specialist greengrocer? – let me know if you can find them!)  However, they look cute and taste great!  They don’t need peeled (luckily!) and taste great raw.  Wash them, slice them and you’ve got a lovely crisp, citrusy ingredient for a winter salad!  And think how much you would pay (in money and carbon emissions) for salad vegetables in the UK in winter!  However, if you don’t fancy winter salad, these can be cooked like potatoes. Unfortunately they lose most of their taste this way.


It was a nerve wracking wait in the spring of 2021 to see if the plants grew back!  In May, I saw the first signs (nearly swamped by a couple of weeds which were hastily removed!) and by June all of the plants were establishing nicely – even the one I’d raided during the winter! This year, I’ll need to make sure any reviving oca plants get moved into new soil, to stop pests building up. If considering crop rotation, treat oca like a potato. Another option is “interplanting” – onion and garlic have been tried as they will be harvested before the oca needs more space and sunshine.

oca growing back in second year 14/06/21
plant re-establishing in second year

In 2020, I could only get these as plantlets. Since then, I’ve seen tubers for sale which are much cheaper and more likely to survive posting! If you have a go at growing these, do let me know how you get on!


  1. cheryl lannon

    Very informative, nice balance of information, facts and humour.

  2. Amalia Banteli

    I had never heard of ocas before they looks delicious! I would be very curious to try the stems and leaves too – would they be boiled, like a swiss chard?

    Overall, very interesting, love the step by step narration, the trial and error with growing them and the analysis at the end!

    • Vicki Stevenson

      many thanks for your comment and query! The flowers and leaves are edible too (haven’t found information specifically on the stems though). Just be careful as the leaves contain oxalic acid so should only be eaten in small quantities. Oxalic acid can reduce the body’s ability to absorb calcium and can aggravate rheumatism, arthritis, gout, kidney stones or hyperacidity.

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