New Zealand Yam/Oca advice please

Hi NVG. I was also given some oca by another kind grape when I was on a trip to England Maybe the same one as you. And I was looking for advice on when and how to harvest it. What I've read at the Real Seeds website and other places is that it should be left in the ground as long as possible because it only starts making tubers when the days get shorter in the late autumn. They say to let the frost kill it completely, and then wait at least another week, because the nutrients from the dying top growth will go down to the tubers and they'll swell up some more, maybe to double the size. My plants survived the first light frost here, but then we had several nights of heavier frost starting about 2 weeks ago, and now the tops are dead and almost completely gone. So I'll probably dig them up in the next day or two before the next spell of freezing weather. Looks like your weather has been milder than ours so you're probably better to leave them a bit longer. But maybe someone with actual experience of growing them will come along and give you different advice.

How to grow and harvest Oca tubers - instructions from The Real Seed Catalogue

Nope - you're bang on Zelenina!

I leave mine for 2 weeks after the killing frost. They store the same as potatoes. You can leave them in the ground till you need them, but beware voles and slugs, both of which like them a lot.

It really does make a big difference leaving them the last week or two after the frost- the first year I grew them, I dug 'em up too soon, and the tubers were tiny , with really thick roots joining them.

I'm in the silly position of hoping for a proper frost to kill mine now, so's I can harvest. The top growth just won't die...

YAAAAAYYYY!!! OCAAAAAA!!! PRETTYYYYY!!!!



I could've left them in longer because our weather got a few degrees warmer, and there's no sign of a big freeze setting in just yet. But I gave in to curiosity, and worries about them getting eaten by something, and dug them up on Sunday.

I'm delighted with this harvest from two plants at my first time of trying. And now I understand more about how oca grows and tuberises, so I think I could do better next time.

There were quite a lot of small tubers, and some tiny ones only just starting to swell up. So I think I would've got more big tubers for eating by leaving them longer. But the small ones will be fine for planting again.

I also noticed that the tubers were growing on the buried stems rather than the roots. And some were growing on surface stems that had been covered by fallen leaves from a pear tree. So I think it would be a good idea to deliberately cover the stems in autumn with soil or used potting compost or dead leaves etc. This might encourage a lot more tubers to grow. NVG, you could try that if you still haven't dug yours up.

I started with four or five small tubers, a bit bigger than big peas, kindly given to me by Hamamelis last January. (Big Thanks! ) When they started to sprout I put them in egg boxes in a light cool place to chit, the same as seed potatoes.

After a while, since they were small tubers and were getting very shrivelled, I decided to plant them in pots to keep them alive. They soon grew into plants that looked like a giant version of Oxalis weeds.

When it was warm enough to plant them out, I started by only planting two in a spot that's damper and shadier than most of my garden. (We get hotter, dryer summers than in the UK).

I kept the others in pots a while longer because I was afraid of Spanish slugs devouring them all. That was a mistake, because the two I planted out survived and produced tubers, but the ones I kept in pots sulked, and then when I eventually did plant them outside they died. Maybe they would have been ok in bigger pots.

So that's two successes. My first oca harvest and my first Grapevine piccie posted

I also harvested my first NZ yams this weekend but the tubers had a lot of slug damage. Can't really see a way around this for a crop that is harvested so late in the year, given my plot is clay and gets pretty damp and waterlogged. Bit disappointed as I come from New Zealand and was quite nostalgic about the thought of growing NZ yams, used to love them as a child.

Thanks for the updates Zelenina and TrixC. I was going to go and have a quick prod about yesterday but it started bouncing with rain. So planning to go down this morning and look. If the slugs are enjoying themselves to munching on them I will get them all up.

Let us know how you get on.
I planted about 6 in pots , they grew about 25cm high but then got forgotten and not watered so I'm feeling really guilty...I best man up and see what's become of mine

I gave one to my moms friend and she put hers in a large pot in her greenhouse. It grew massive and she was well impressed with it.

The yams are up

Well I went to check on them and some of them were actually sat on the top of the soil. So I pulled the first one up and found a couple had been nibbled so decided that I would get the whole lot up now. I can live with diddy ones can't live with loosing a crop though.

So wait for it, I am well impressed. For 3 tubers I got 1.2kg up. Scales actually said 1202g.

The longest one is about 5 inches

Here are the pics I have taken.

Those look great!
Well done!

what do they taste like ? the only yams iv'e ever come across where great big things that where fed to catle ... atb Dal

They taste a bit well nutty. I a few boiled. I tried a bit raw as they are meant to have a citrus taste but I couldn't taste it very well. I read somewhere that if they are exposed to light then they turn a little bit sweeter. So have a few out in the kitchen to see if this works. The rest are tucked away in a box ready for planting again this year. Nearly typed next year then

They're not a yam in the sweet potato sense, they're a completely different kind of tuber. I've had them boiled and steamed. They're supposed to have a hint of lemon, they do have a slight tang, not sure if it's lemon exactly but it is quite a pleasant tang. I've just been eating them with salad and plan to grow loads more this year along with a few different tubers (ulluco and yacon).