How to grow wasabi

Add this fiery root to your growing repertoire for big, flavour-packed returns

Wasabi (otherwise known as Japanese horseradish) is a fantastic choice for growers looking to add something a little different to their plots – and something that packs a real punch in the kitchen, too!
Wasabi should be grown in well-drained soil which has had plenty of well-rotted manure dug into it prior to planting. They are also well suited to container cultivation, so small space growers needn’t miss out. If you will be growing in pots, allow about 30cm between each plant, or one plant to a five-litre pot.
You can grow wasabi from plants, root sections, specially propagated plantlets or even seeds – but seeds are tricky to come across so it is usually best to grow from young plants or plantlets.
You should water the plants to keep them constantly moist but never saturated, and be sure to protect plants from slugs in summer, as well as providing light shade. Once 15cm long and 5cm in diameter, lift the roots, removing any offshoots, which can then be planted for the next crop.
To emulate conditions in Japanese wasabi farms, some growers make lined beds, which are then filled with gravel, into which wasabi plants are set, so flowing water can feed them and then be recirculated. These beds are usually in polytunnels or beneath cloches to give the plants the high levels of humidity they require to flourish.
Wasabi dies down in winter and the slightly tender roots should be protected with a covering of straw.
If the plants are grown in pots, take them into a shed or greenhouse to escape the unfavourable weather conditions of winter. Look online for specialist suppliers who stock wasabi plants and roots.
Wasabi is susceptible to the pests and diseases that afflict other garden brassicas, but it is rare for them to cause significant damage to these plants