Most of the time, the wasabi you get in a restaurant or buy in a store is fake.
It’s actually horseradish that’s colored green. Why? Well, wasabi is a notoriously difficult plant to grow. In fact, it’s considered the most difficult plant in the world to farm commercially. Yet for the past century, the Daio Wasabi Farm in Hokata, Japan, has been growing it successfully with natural spring water from nearby mountains.
In the video by Great Big Story you will see that Wasabi is quite picky about its growing conditions. Wasabi prefers cool, shady conditions and will sometimes thrive if left undisturbed in misty mountain stream beds. It generally requires a climate with an air temperature between 8°C and 20 °C and prefers high humidity in summer.
These stringent demands to grow the wasabi root along with the 15 month wait and high demand is what leads Western sushi restaurants into using the powdered synthetic variety.