Wasabi has made it to Europe, at least in name. Because what is sold as wasabi in this country is usually just colored horseradish. If you want to taste the original, you have to dig deep into your pockets or grow the plant yourself.
How can you grow wasabi yourself?
To grow wasabi successfully, you need a seedling or seed, a shady, cool and moist location, regular watering and nutrient supply, and constant temperatures. Harvesting takes place after 2-3 years when the rhizome is strong enough.
Starting with a seedling
Wasabi is a perennial herb whose fleshy root is only ready for harvest after two to three years. Cultivating this plant only makes sense if it is intended for a long period of time. You can start with small seedlings, which you can get for just a few euros in stationary garden shops or in online shops (€9.00 on Amazon).
The somewhat difficult sowing
Wasabi can theoretically be grown from seeds, but there are several problems that await the hobby gardener: The seeds are difficult to obtain in this country, they do not germinate reliably, and it takes even more time until harvest. If you still want to try it, you should note the following points:
- sow in spring
- Keep soil moist throughout
- first separate after germination
- plant later
Suitable location is rare in the home garden
In its native Japan, wasabi grows on the rocky banks of mountain streams. Such a humid environment is not easy to find in the home garden. A spot close to the pond would be an alternative, but it would have to be in the shade. If there is no damp place, watering must be done diligently. Nutrient-rich soil and constant temperatures are two further growth factors.
Safe cultivation in pots
Since wasabi's frost tolerance is not sufficient for harsh winters, it is often recommended to plant it in pots. The pot should have a drainage hole and a drainage layer so that water cannot accumulate. It must also be at least 30 cm deep because the wasabi forms a long root. The substrate used may be clayey. Also make sure you find a shady and cool place for the pot.
The optimal water and nutrient supply
The soil in which wasabi extends its coveted roots must always be kept moist. But the water must not stand still! It is recommended that the soil dries out a little before watering again. You shouldn't be stingy with the amount of water so that the moisture gets through to the lowest layer. There should always be a saucer filled with water under a potted plant. According to needs, the wasabi is watered more modestly in winter.
It is completely sufficient if wasabi is supplied with flower fertilizer once in spring. This gives the otherwise sluggish growth of the plant a boost.
Tip
During the growing season, make sure that the wasabi is surrounded by a temperature between 15 and 20 °C.
Winter wasabi safely
You should overwinter potted specimens at temperatures just above 0 °C. For example in an unheated winter garden or greenhouse where there is still some daylight.
When planted out, the wasabi will survive temperatures down to around -8 °C, but must be protected with a thick layer of bark mulch or leaves:
Harvest readiness
Even if the green leaves of the wasabi are quite attractive, its rhizome is the piece of desire. After about 2-3 years it will be strong enough for harvesting to begin.
