Walk on the wild side this season and grow some unusual tubers
Organic Yacon - Smallanthus sonchifolius
These perennial tubers from south America, look like a potato, grow like a Jerusalem artichoke, and taste a bit like a pear. Easy to grow and store, high-yielding, super nutritious and crunchy like an apple.
- Yacon is a perennial plant, so once you have planted it, so long as you look after it, you will have it forever. It is easy to grow in most soils where there is reasonable rainfall and moderate heat. They are large plants growing to a height of 2m+
- Underground, it grows a bit like a dahlia - with a small clump of knobbly growing tips/rhizomes and large storage tubers radiating out in a circle. The large edible tubers act as the energy storage facility for the plant, and the smaller propagation roots (resembling Jerusalem artichokes) which grow just under the soil surface and are the seeds for the following year's growth.
- When harvesting separate the reddish rhizomes from the tubers and wash off any soil, taking care not to break the skin. The brown tubers (for eating) are dried in the sun and then stored. The reddish rhizomes (for next years plants) are kept out of the sun and covered with slightly damp sand or sawdust to stop them drying out and stored in a dark, dry place.
- In early spring plant the rhizomes into large pots and wait for shoots to start growing. When the shoots have formed split the rhizomes into individual shoots with their tubers attached and plant into smaller pots. Yacon plants are quite sensitive to temperature, so plant them out when you would tomatoes, a metre or slightly more from their neighbour, in a sheltered, sunny spot. Needs good fertile soil.
- The tubers and leaves contain high levels of inulin, a form of sugar humans cannot easily break down, making it low in calories. Inulin also aids digestion and promotes the growth of beneficial bacteria in the intestine, while inhibiting toxic bacteria. Recent research also has found that yacon tubers and leaves are a good source of antioxidants. Yacon is an ideal food for diabetics.
- Yacon tubers develop into autumn, and as the frosts approach it's worth putting a little straw around the plant to protect the tubers. The leafy growth is withered by the cold – as soon as this happens, use a long fork to gently lift the tubers. It helps to have another person pulling on the stems of the plant at the same time to get the whole plant up.
- Snap the large tubers from the crowns. They're crunchy, tasty and refreshing immediately, but a few days in the sun can add to their sweetness.
- You should expect about six large tubers from each plant – but the yield will increase with time.
- A cool, dry shed or garage is perfect for storing yacon tubers until you're ready to eat them. Will sweeten more over time
- Yacon has a crunchy texture, slightly reminiscent of water chestnuts, and a sweet flavour, so it's rather good simply peeled, sliced and eaten as a snack.
- Good in salads, though its tendency to brown means that you should add it at the last minute, once everything else is assembled and ready to be dressed, or sprinkle with a little lemon juice to prevent it discolouring as it's peeled.
- Yacon also can be stir-fried, roasted, baked or made into pies and healthy chips.
Organic Jerusalem Artichoke - Helianthus tuberosus
Not hailing from Jerusalem, nor an artichoke, but a species of sunflower which produces masses of edible tubers. Jerusalem artichokes originated in North America and were introduced to Europe by colonists. Fond of the climate here, they grew prolifically and have been used since for both animal and human fodder as well as to ferment into alcohol.
Jerusalem artichokes are very easy to grow but some things are worth considering -
- They are large plants which can be between 1.5-3m high so be careful not to put them where they will shade out your other crops.
- From April, plant into well-prepared soil at a depth of 10-15cm with tubers spaced 30cm apart. Row spacing 1m.
- When stems are around 30cm tall, draw soil around them to a depth of 20cm to help stabilise plants as they grow.
- You can cut back stems (including flowerheads) to around 1.5m in midsummer so plants won’t be rocked by the wind, thus avoiding the need for staking.
- When foliage starts to turn yellow in autumn, prune to leave 10cm stumps above ground level. Place the prunings over plants to keep the soil warm and aid lifting of tubers in frosty weather.
- Can be left in the soil and harvested as needed. If you have heavy wet soil it is best to lift and store them.
- Harvest the tubers as required with a garden fork from late autumn into winter.
- Jerusalem artichokes are persistent, so if you don’t want them coming back the following year, make sure you remove every last one - tubers left in the ground will regrow into a large plant the following spring.
- Harvested early they taste earthy. If left in the ground longer and exposed to the cold winter months they become sweeter.
- You can cook Jerusalem artichokes peeled or unpeeled. Scrub them with a stiff brush just before you cook them. Sorting your tubers by size will simplify preparation.
- Medium-sized Jerusalem artichokes that have numerous bumps and knobs can be boiled whole in their skins and then mashed and sieved to form the basis for Jerusalem artichoke soup, which many say is the best way to eat the veggie.
- Rather than struggling to peel small, knobby tubers, scrub them well and then roast them with a little olive oil and sea salt. After they’ve cooled, eat them as finger food by squeezing the soft middle into your mouth - a North American food practice that dates back more than 1,000 years!
- Jerusalem artichokes get their sweetness from a unique sugar called inulin, which the body metabolizes much more slowly than it does other sugars. This makes the veggie a preferred food for diabetics, and for anyone who wants to avoid eating simple sugars and starches.