Planting Jerusalem artichokes: how & when?

Jerusalem artichoke is a close relative of the sunflower. It is not only beautiful to look at, but also produces delicious tubers. Read on to find out how to grow Jerusalem artichoke tubers at home.

In the 17^th century, Jerusalem artichoke (Helianthus tuberosus), also known as topinambur, sun choke, sunroot, wild sunflower and earth apple, left South America and arrived on the shores of Europe. For some time, the brown or red tuber, which tastes a little like globe artichoke (Cynara scolymus), was a preserve of the rich and noble. Soon, however, it spread to the common folk, and became an important dietary staple.

Over time, this fibre-rich tuber was replaced by the potato (Solanum tuberosum). Jerusalem artichoke disappeared from our plates, and was only grown as cattle feed. Now, Jerusalem artichoke is back in vogue, and very popular with hobby gardeners.

But when should you plant Jerusalem artichokes? And how do you care for them? Here is our step-by-step guide on planting and cultivating Jerusalem artichokes in the garden.

When to plant Jerusalem artichokes?

The best time to plant Jerusalem artichokes is in spring, between early April and mid-May. Alternatively, you can plant the tubers in autumn, between late September and early November. Autumn-planted tubers will not sprout until the following spring, but they tend to arrive slightly earlier than tubers planted in April and May.

Note: Unlike potatoes, Jerusalem artichokes are winter-hardy, so you can plant them at various times and leave them to overwinter outdoors.

Growing Jerusalem artichokes: location and soil

Jerusalem artichoke is not a picky plant. It prefers full sun, but grows in partial shade. Above all else, it likes light, loamy and sandy soil. This is because the plant needs plenty of water to produce quality tubers, so the soil needs to retain moisture, but waterlogging stunts tuber growth. Simply put: the better the location, the higher the yield.

You can rotate your tubers with other cultivars, but do not plant Jerusalem artichoke in a location previously occupied by sunflowers or by another Jerusalem artichoke. Otherwise, you increase the chances that your plant will suffer root disease. If nothing else, any root diseases present in the soil will remain there for much longer if your Jerusalem artichoke is replaced by, for instance, a sunflower.

Companion planting is also a good idea. As is always the case with companion planting, some neighbours get on well with Jerusalem artichokes, and some do not. In particular, the tubers grow well with climbing cucumbers (Cucumis sativus) and French beans (Phaseolus vulgaris), but not potatoes, which compete with Jerusalem artichokes underground.

Tip: Jerusalem artichokes make a great screen, as they can reach a height of over 3 metres, depending on the variety. However, be sure to place the plants in a location that has as much shelter from the wind as possible, or tie them up, as thunderstorms and gales can easily break the plant’s stiff branches, or even knock over the entire plant.

Planting Jerusalem artichokes

It is important to only plant healthy, whole tubers. Although you can cultivate Jerusalem artichokes from seed, planting the rhizome tubers is much quicker and simpler. The seeds are hard to find in shops, and few varieties come to maturity in our climate, so it would be difficult to save the seeds yourself.

Planting Jerusalem artichoke tubers: step-by-step instructions

1. Before planting, place the tubers on a plate of water on a bright windowsill for a few days. Fine roots will soon form on these tubers, which will speed up the growing process later on. Alternatively, many nurseries sell young plants that already have several shoots.
2. Loosen the soil and remove any stones. For nutrient-poor or very heavy soils, work in some mature compost before planting.
3. Plant the tubers about 30 to 40cm apart and 10 to 15cm deep. Leave a distance of 70 to 80cm between the rows. If your tuber already has shoots, plant them at the same depth, but make sure you leave the green shoots exposed.
4. After planting the tubers, lightly press the soil and water generously.
5. When the first shoots appear, form a mound of soil around them. This helps develop more tubers, because the heaped soil warms up more quickly and offers more space for each plant.

Tip: A root barrier for Jerusalem artichokes is useful, especially if some tubers are left in the soil during harvesting. Every tuber, no matter how small, produces new shoots in all directions to maximise its spread. A rhizome barrier is a great way to prevent this spread.

Planting Jerusalem artichokes in pots

If you are looking to grow your Jerusalem artichokes on a sunny balcony or patio, have no fear – the tubers grow well in plant pots. In fact, some less vigorous varieties are particularly suitable for balconies and terraces! Just make sure that your pot is large enough and deep enough; it needs to hold enough soil for the tubers to grow fully.

As with garden tubers, potted Jerusalem artichokes need plenty of water. This is true not only after planting, but throughout the growing season. However, to prevent waterlogging, make sure your container drains water well. After the tubers sprout, mound up a little soil around the plants and fertilise regularly with a liquid fertiliser, such as our Plantura Liquid Tomato Food.

Large window boxes are also suitable for growing dwarf Jerusalem artichoke varieties, or, alternatively, opt for a raised bed. To cultivate Jerusalem artichokes in a raised bed, it is important to fill your container generously with a nutrient rich potting soil. Our Plantura Organic Tomato & Vegetable Compost is a great choice. It contains essential nutrients, like potassium, that support tuber growth for months. Simply place the tubers individually in the soil, lightly press down and cover with about 15 cm of soil.

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Tip: Flowers are not important for tuber formation, so feel free to decorate your home with them. In fact, flowerless Jerusalem artichokes may form more tubers because they are not wasting energy on flower development.

Another dietary staple, and close relative of the Jerusalem artichoke, is yacón. Read our in-depth article to learn all about this South American tuber!