I talked with my guy over at NovaBarrel.com, and he has seed potatoes that he'll throw in with the barrels for an additional buck. And these aren't just any potato - they're purple potatoes - particularly high in anti-oxidant goodness. And they're not GMO'd to get that deep purple color. They hearken back thousands of years, and were the food Incans reserved for their kings, according to this Chicago Tribune article.
So while I'm out there, I'll go ahead and pick up a barrel or two and some purple seed potatoes. Looking forward to seeing how that works out!