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 starch. It is therefore highly promising as a way to introduce sweetness in to the diet of diabetics.
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 for them. 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 to a large pot with good quality potting compost. Place the pot on a heated bench or sunny place in doors.
Plant out in the ground in May, being careful of the weather - a good guide would be to only plant them out when you 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.
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, also storing in sand.
Oca and Yacon are far more palatable raw then 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.
There are no varietal names.
It is blight resistant just like Oca, and almost completely immune to problems..