IT IS AN enormous plant that produces huge tubers that can be eaten raw or cooked. Though the yacon looks like a very large potato, it has a surprisingly sweet, apple-like taste and a juicy texture.

It’s creating quite the buzz among nutritionists because of the unusual way it stores its carbs – as indigestible sugar (insulin) rather than as starch. It is therefore highly promising as a way to introduce sweetness into the diet of diabetics.

Sowing

In our climate, yacon will do best in a polytunnel or greenhouse but can be grown outside if you have a very sheltered, sunny spot. Similar to potatoes, it is grown from tubers from last year’s crop.

Yacon grows two types of tubers – the knobbly “stem” or root tubers that grow just under the surface around the stalk of the plant and look a lot like Jerusalem artichokes, and the large, smooth edible tubers that grow outside of these. The former are the ones used for propagating the following year’s crop, while the latter are for eating.

As with oca last week, getting your hands on the tubers can be a challenge – they are a rarity – but on the plus side, once you have them you will never need to buy more.

Separate the knobbly tubers in spring, making sure you have a growth point on each. Plant each one in a large pot with good quality potting compost. Place the pot on a heated bench or sunny place indoors.

Growing

Plant out in the ground in May, being careful of the weather – a good guide would be to only plant them out when you’re happy to plant out your tomatoes. Space 1 metre apart. Water regularly.

The plants can be slow to get going but in the summer will get to a height of 2m. As it’s a hungry plant, it’s a good idea to ensure the soil is good and fertile with plenty of added compost or farmyard manure.

Harvesting

Like oca, yacon tubers do a lot of their growing late in the season, so leave the plants to be killed off by the first frosts in winter. Then, dig the whole plant carefully – the yield will be 5-10 large tubers per plant. Snap these off.

They will store in a frost-free shed in a box of sand and will sweeten further over time. Cut the stem of the plant back to about 10cm and store this “crown” with the knobbly root tubers attached for next year’s crop in sand.

Oca and yacon are far more palatable raw than the potato, and yacon is surprisingly sweet and tasty as a raw snack. Cooked, it has a variety of uses – basically anything you can do to a potato.

Recommended varieties

There are no varietal names.

Problems

It is blight resistant just like oca, and almost completely immune to problems.

GIY Tips

Yacon was valued by the Incas for its thirst-quenching qualities. Yacon is related to the dahlia.

GROW HQ

The home of the GIY movement, GROW HQ, is finally open in Waterford city. In addition to our 65-seat home-grown food café and shop, we’ve a range of growing and cooking courses happening weekly. For courses happening this month and for the perfect voucher for Christmas, check out www.growhq.org.

Recipe of the week – Yacon and blue cheese salad

Shutterstock / vanillaechoes Shutterstock / vanillaechoes / vanillaechoes

It’s not easy to improve upon the famously fabulous combination of walnuts and blue cheese but this recipe from our good friend Mark Diacono uses yacon to create a deliciously different lunch.

Serves 4 as a starter. Recipe from A Taste of the Unexpected by Mark Diacono (Quadrille).

Ingredients

• Small handful of shelled walnuts or pecans
• Juice of 1 lemon
• 1 medium-large yacon
• Handful of salad leaves
• 180g blue cheese, such as cashel or dorset blue, roquefort or gorgonzola

For the dressing

• 1 tbsp apple balsamic vinegar
• Pinch of flaky sea salt
• 3 tbsp extra-virgin olive oil

Directions

Preheat the oven to 180C/Gas 4. Spread the walnuts or pecans out onto a baking tray and toast in the oven for 8–10 minutes, shaking halfway through, until lightly coloured. Keep an eye on them to ensure they don’t burn.

Fill a bowl with water and add the lemon juice. Peel the yacon, cut into slices and toss into the lemony water to prevent them from discolouring.

In a small bowl, whisk together the vinegar with the salt before adding the olive oil a little at a time, whisking all the while until smooth. In a bowl, lightly dress the salad leaves in a little of the dressing and divide between 4 plates.

Arrange the sliced yacon on top, crumble over the blue cheese, then trickle over the rest of the dressing. Scatter the nuts over the top and serve immediately.

Michael Kelly is a freelance journalist, author and founder of GIY.

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