I second the chives, if you use chives. If you have a separate barrel or planter, you could start a perennial herb selection, too. And, if you like basil (an annual), clear yourself a little ground and scatter some sweet basil seeds and harvest some summer pesto. Super easy.
Everybody keeps saying that potatoes are easy. I tried the 'potatoes in a barrel' method (in my case, a trash bin) because it offered space-savings. I got lots of foliage, but crap results in tubers. I pitched that idea and have never returned to trying to grow potatoes. I think that growing potatoes takes a fair amount of work and you need to keep on top of adding more soil and mulch. Miss adding soil and you end up with poisonous purple potatoes.
I don't grow cucumbers because I detest them, but my father never seemed to have much problem with them, so I tend to view them as all too easy to grow.
I never added soil to my potatoes, I just dug holes for some spuds, covered them up and forgot about them for a couple of months. Wasn't a huge harvest, but it very satisfying to eat a staple you grew in your garden.
Rye is one I see a lot, and we grow some sugar beets, potatoes, and lots of rapeseed. Oats and barley are not uncommon, and we do see wheat at least here in the South. And quite a lot of cleared land is left unplowed to give hay for the winter. But the forests are the green gold.
There is a stark difference from, say, Central Europe when you look down at the landscape from a plane; in Central Europe you see lots of rectangular fields that cover most of the ground in a tetris-like mosaic, while in Finland the view is more of occasional small irregular fields often all but drowned by great swaths of forest and lakes.
Um...It's one of those things I've always thought of doing, but never actually followed through on it. I have to say I have not.
But, it should be easy. It's basically a self-replicating bulb. In the floral garden biz, they are allium and produce a ball-shaped flowerhead. They are supposed to be natural garden pest prophylactic plants (against aphids, if memory serves). It should be cheap and easy to try. I will pot-grow this year....for the pesto!
These would probably be lost most often to rot (too much moisture for too long) or slug/snail depredation. Plant at multiple sites. It is perennial, so if you fail to harvest, it will return the following year.
I should try some horseradish, too. Same deal, but I think it looks more like an invasive pest plant than garlic does.
I went to the garden store today and brought home four more raspberry canes and two bags of worm castings soil amendment.
I was sorely tempted by the rhubarb and told myself that I had to have my ground prepped before I hurried back to get another rhubarb root. Plus, I need to check how the one I planted last year is doing.
They had bundles of strawberry plants! Watch out eastern front!