When you're a kid, there are certain things you learn and take for granted. You know it, so everyone else must know it. That you never leave for camp without a hat (to protect against ticks) and a sit-upon (to sit upon). That the second verse of "Fried Ham, Fried Ham" should properly be done in Underwater Accent. That irises bloom in June, right before your annual ballet recital. And that when you are hungry for a snack, you could do worse than reach into the fridge for some kohlrabi.
And then when you're an adult, you realize not everyone knows the same things. It is probably a pretty small segment of the population that knows the words to "Fried Ham", for example. And whenever you mention kohlrabi, people have no idea what you're talking about.
It's kind of like jicama, if you know jicama -- which more people seem to, now. And I don't know if my familiarity with kohlrabi is more of a Midwestern thing or more of a gardening thing. I remember distinctly the first time I read "cardoons" on a menu and had to ask what they were. But kohlrabi? Feels like I've always known.
Anyway, if you see kohlrabi (cahl-rahb-ee) in your farmer's market or grocery store, give it a try. They might be "white", like the above, or purple. Pull off the noodly bits, cut off the unchewable skin with a paring knife, and slice the rest. You can cook it like a turnip, I hear, but I have only ever eaten them raw. Slice. Munch.
It's like a jicama, but less watery.
It's like a radish without the bite.
It's like kohlrabi. Try it and you'll know.