A perennial root vegetable that has juicy tubers that look like sweet potatoes, felty leaves and small daisy like, yellow flowers. They are harvested in December and have the texture of water chestnuts and the taste of the inner sweet core of carrots (according to a friend). They grow from the rhizomes rather than the tubers. Tubers contain inulin and become sweeter if left for a week on a sunny windowsill.
December is a good time to talk about yacon. As the frosts arrive, the yacon plants are shrivelling. They are a little-known, perennial root vegetable (in the UK anyway). I had only heard of it a couple of years ago as I strove to make my garden more perennial. So – like potatoes, yacon roots will swell to form tubers for winter storage, unlike potatoes which propagate from these tubers, the yacon also has rhizomes which will grow shoots in spring to form the new plants. I’ve read that the tubers also can be used to grow plants – but if you have these much less tasty rhizomes there for propagation, why would you not eat the tubers?
I’m not overly fond of perennial root vegetables, if I’m honest, as it requires more work than I like. For me, the perfect plant is one I plant one year and then for ever after (or at least for many years after) I get to harvest something from them. I don’t mind if it takes a couple of years for something to get going, but once it’s going, I prefer to pick fruit, leaves, nuts, stems… basically something that doesn’t require pulling up and replanting every year. I love low maintenance self-seeders too, like winter purslane or nasturtiums.
What does a yacon taste of?
This is the first thing to talk about because this is the reason I grow it, despite my laziness. It isn’t available in the shops and its taste and texture is very unusual. Basically, raw, it has the texture of water chestnuts. For anyone who hasn’t had water chestnuts it’s like a radish, but brittle. Radishes (like carrots) I would call crunchy. Yacon is more, what I’d call crispy – like a crisp apple. Aaaargh! It’s difficult to describe. Now, the taste is something between apple, carrot, pear… celery? Or as my neighbour said – core of a carrot. Someone mentioned a slight honey taste. When freshly picked it doesn’t taste that amazing, but when left to ‘cure’ on a sunny windowsill it turns unexpectedly sweet. The texture gets a little softer, but that’s a price I’m willing to pay for the sweetness. After some cold weather, if left in the ground it also gets sweeter, though not as sweet as those cured on the windowsill. If anyone has the vocab to describe both the taste and the texture please comment. I really am stuck!
From what I’ve read, yacon has a sugar in it called ‘inulin’ which human digestive systems can’t process – so it’s supposed to be great for diabetics and those wanting to lose weight. Just a warning though, if you eat too much you get rather windy. This is because the inulin is instead digested by our gut bacteria creating gases in the intestines. It is, therefore, reportedly good for gut health as a prebiotic (something that feeds the bacteria as opposed to a probiotic which is something that contains lots of healthy bacteria to populate the gut).
I’ve never seen these available as seeds. They are also not available from the usual companies. They can be found online on websites specialising in perennial vegetables or on eBay. They’re sold as rhizomes or young plants. I suspect young plants are the safer option as you’ll know it survived and rhizomes could’ve been damaged if not stored properly. Rhizomes are easier to send in the post though.
This small plant is then potted into fertile compost when all danger of frost has passed and basically left until the first frosts in winter kill the plant above ground. The more fertile the soil and the sunnier the spot, then the more likely it is that you’ll get many big tubers. They also need sufficient water for lovely juicy tubers. They don’t do well in our clay, stony soil so we only grow them in planters or very (I really do mean very) large pots. They are great for pots though as it makes for an easier harvest.
The yacon have velvety spear shaped leaves with slightly jagged edges. The stems go purple at the base and the flowers are yellow and about the size of a 50p. Depending on the fertility of the soil and the size of the pot the plant can be 3 to 5ft at maturity. They are also rather bushy.
When the plant above ground is dying you can start harvesting yacon. This year we began at the end of November because I had run out of veg in the house. All you need to do is grasp the bottom of the shoots and gently and slowly wriggle the whole thing out of the soil. The roots are fairly brittle and the skin of the tubers quite delicate, so you need to be kind. When you’ve pulled the while thing out it will be fairly obvious if any of the tubers have broken off and been left in the soil. Alternatively, if they are grown in a pot you can shake the whole pot out and extract the whole root system.
You can stagger the harvesting as the tubers don’t go mushy in the ground after a frost. They can get sweeter with some cold weather. The plan so far is to harvest every 2-3 weeks to keep a continuous supply.
Once the roots are out you snap or cut the tubers off from the rhizomes. The stems and the dead leaves can be cut off the rhizomes and composted. The rhizomes can then be stored in some damp (but not wet) compost till spring. If you’re worried about the winter weather, they can be put into a shed or something. Mine have survived the winter fine outside so far but the winters have been mild here.
In the spring check the rhizomes for any sprouts. You may get several sprouting tips on each rhizome which can be cut into chunks according to sprouting tips and grown as separate plants.
Storing and eating yacon
Let the yacon dry indoors for a day so the soil dries and can be brushed off with gentle fingertips and place on a sunny windowsill for around a week or two to ‘cure.’ Now, literature says that they shouldn’t be washed as scrubbing damages the skin and leads to mould. What if I didn’t scrub?I believe that they’re fairly damp when they come out of the soil so is there anything wrong with giving them a little rinse immediately after harvesting and patting dry before curing or storing in the fridge? I harvested a batch yesterday morning (12th Dec) and I’m going to try washing them and I’ll post in comments next week the results of washing.
You can eat them fresh, cured or anything in between the two. Curing makes the yacon sweeter (to the extent that it can be as sweet as an apple) but the yacon will be less firm (slightly rubbery to touch but oddly it’s still got that bite when eating) and it’s harder to peel because it’s a little soft.
The skin can be bitter so they should be peeled. The yacon will then discolour, it goes a very dark green (almost black) colour, quite quickly after peeling, especially one that has been cured. They still taste fine though. Because the skin was so thin, one time, I tried just scrubbing them the way you can carrots. This was a bad idea. They were still bitter on the surface and the water went very dark green and I ended up having to peel anyway. Just an FYI, the juice of the yacon feels sticky on your hands and is hard to wash off.
They are very juicy when eaten raw. They’re great chopped into salads. They maintain structural integrity when stewed. They have a pleasant bite when fermented with kimchi in the place of carrots. They can be roasted or sautéed. The absolute winner for me is that my little monkey loves them raw as a snack. Prebiotic veggies into child… that’s a mummy win… and she has no trouble letting one rip when the gas builds up!
6 thoughts on “Yacon”
LOVED reading this segment. Been thinking of your blog for a while now and finally got round to reading this part on the yacon. I remember seeing your post describing the texture of water chestnuts which I adore. After reading your blog on them a there’s so many reasons why this plant is a WIN!! Especially love it’s perennial. Brilliant.
P.s how did they do after you washed them?
Lovely so see you on here Charlotte. Thanks for reading. They do have a great texture. It is perennial… but be aware that they whole plant gets uprooted and then replanted so it’s not the easiest perennial. It does mean it is sustainable to just keep growing them year on year. They were actually fine after washing if left to dry properly before putting on the windowsill for a week. I put some in the fridge (again after washing and drying) and after 3 weeks they’re still fab. I think they may have gotten a little sweeter too. I’m going to see how long they last in the fridge… that is if we don’t eat them all first. They store fine in the soil if the temperatures stay cool, the soil isn’t waterlogged, the tubers aren’t broken and there isn’t a hard freeze to freeze the tubers.
Thank you for the detailed overview of yacon. I’ve recently harvested my first ever crop and have been very impressed at the volume, taste and all round usability of this plant. Potatoes will always be my favourite tuber, but yacon could well turn out to be a good second, so very glad I’ve discovered them.
Similar to you I also have heavy clay soil, but as I wanted to grow them in the ground I applied lots of organic matter and this seemed to help. The tubers were down in the clay level, but with some very careful and patient excavating, most of the tubers came out intact. And they were large.
December 2022 has had a very cold week or so (minus 5 at worst), but my plants were thickly mulched and all of the tubers in the ground seem to be fine. I did store a few that I’d harvested in a cold shed overnight and they succumbed to the frost (turned translucent), so that was an error, but apart from that they’ve been pretty much trouble free.
Hopefully the rhizomes will overwinter and I’ll have a bumper crop next year.
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It’s wonderful to hear that you had a great first crop. Potatoes will always be more versatile than yacon and for me a great comfort food. I like to think of the yacon as more of a nutritious vegetable rather than a carbohydrate providing one.
I know your pain. I left my harvest too late this year and the tubers were frozen solid into the soil. Well done for being prepared and mulching. I was also surprised at how much the cold penetrated. I have some bulbs in compost in the shed that became frozen blocks. I’m guessing if compost had frozen in the shed this year it probably has in previous winters of storing my rhizomes in there. They have always bounced back so hopefully yours will be fine too.