On a chilly grey morning I come across a big, lush patch of nettles in a Pittsburgh park. Leah Lizarondo, the food writer who brought me here, has her hands wrapped in old plastic bread bags.

Those bags are crucial because touching stinging nettles with your bare hands can be pretty unpleasant. "It's like something pricked you, like a little ant bit you, and then it starts being a little painful," said Lizarondo.

But Lizarando says she likes that element of danger when she's on a hunt for wild spring ingredients for pesto. And those weeds plaguing many backyards and parks — like dandelions, purslane, ramps and chickweed — should instead be considered a veritable grocery list, she says.