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.