Guest blog by Ray Shortridge
The Daio wasabi farm followed the business template pioneered by Knott’s Berry Farm — supplement a viable farm operation with a high steady cash flow destination for tourists. Add outdoor cafes, gift shops, and a wide array of wasabi based or flavored products for sale.
Wasabi flavored ice cream, croquettes, etc. for immediate consumption (the wasabi ice cream was a bit bland, but the Fuji apple ice cream was sweeter) and wasabi paste, slivers, leaves, etc. for taking home to mix into dishes.
Wasabi flourishes in a bed of gravel that is flushed by a flowing stream of fresh cool (10-15 degrees Celsius) spring water. 
Farmers scrape the gravel into a grid of ridges that resembles a waffle iron. Wasabi sets are planted on the ridges.
The plant emits toxins to protect it from pests, but if the toxins are not flushed, then the accumulation can destroy it.
The wasabi tuber resembles a potato. However, while the potato tuber grows down, the wasabi grows up. At harvest, the entire plant is plucked. In processing, the leaves are trimmed from their stalks, and then the stalks cut from the tuber.
The leaves and stalks are processed to create a wasabi green food coloring. The tuber is sliced and processed into a paste.
In the Matsumoto region and gourmet Tokyo restaurants, some sushi chefs garnish their sushi dishes with the 100% wasabi paste.
Elsewhere, the “wasabi” on your sushi is a blend horseradish, spices, additives, food coloring, and maybe, just maybe, dash of wasabi paste.
Travels with Owen 