u/Cucumberneck

Here in germany there's a famous legend that Frederic the Great had soldiers guard potato fields so the peasants who didn't want to plant them at first were tricked into believing them to be extremely valuable.

I knew that the French have basically the same tale, then i read that the Greek have the same and today i was informed the Swiss and Finish tell the same tale.

Are there any real sources other than legend for any of this?

I highly doubt that any king or minister would actually plan on the peasentry disrespecting them in such a way.