Quick, what's the most dangerous thing at the farmers' market?
No, not artichokes and not bitter melon. It's not the peyote at the mushroom stand; it's not the tenor from the mariachi trying to sing “Cucurrucucú Paloma” (I am not sorry about that: you should have said no when I requested it!)
No, the most dangerous thing at the Irvine farmers' market is an innocent-looking pile of green leaves at Sweredoski Farms. It lies in wait, hoping for unsuspecting hands to grab it before lancing painful (and surprisingly sharp) spines into the fleshy part of the palm.
You can grab stinging nettles safely by being confident about it: grab firmly and quickly and the plant won't have room to fling its histamine-containing barbs at you. I have succeeded at this, and I have quailed before the task and been stung badly. I suggest you use a second bag to transfer the plants to your bag for transport. And if, after purchase, someone is making a move toward the very last peaches of the season, you have a weapon at hand.
When purchasing nettles, look (as with any leafy green) for fresh cuts, sprightly leaves and no discoloration. Younger nettles are more tender; larger, older specimens have a more iron-y taste and are richer in folic acid.
Once you get it home, don't worry: cooking removes all of the stinging from the plant; you can eat the entire thing, leaves, stems and all. While nettle soup is a very old Central European recipe, the plants taste like slightly wilder spinach. Cooked with a little butter (or, better yet, pork fat), they make a fantastic topping for a bowl of soft polenta–or use them to top crostini made of set, cut and toasted polenta, with a dab of crème fraîche. It also makes outstanding pesto; substitute it one-for-one with those out-of-season basil leaves and add just a couple of fennel seeds for flavor.
Nettles should be available through February or March, depending on the weather.