в японии выращивают просто, ну если верить тому что я на разных видео видел: в мелкую речку натыкают и всё, оно само растёт, никаких удобрений и прочих затрат
> Wasabia japonica has a reputation as being the most difficult plant or herb to grow to a usable product. Much of this reputation arises from the fact that Wasabi requires cool growing conditions and has almost zero heat tolerance. This environment is almost the opposite of most plants that hydroponic growers are used to supplying their crops.