Or you can do nothing, which is what Weaver does, and still gets enough tender white stem—and stock-worthy green leaves—to make leeks a staple in his cooking.
Leek cultivars are subdivided in a number of ways, but generally they fall into two distinct categories. So-called summer or autumn leeks are intended to be harvested in the late summer or early autumn of the year in which they are planted. The more hardy overwintering leeks, as their name suggests, can be harvested any time, even in the dead of winter, as long as winters are fairly mild and the plants have been protected with a thick layer of mulch, such as dry grass clippings or chopped dried leaves, to prevent the soil from freezing. As a rule of thumb, winter leeks are bluer and stubbier than slender summer leeks, although I’ve found that rules of thumb aren’t reliable (for example, the summer ‘Pandora’ leek is dark blue-green and has a fairly thick shaft, so you might pick it out of a lineup as a winter leek).
Leeks are said to have a few enemies, including nematodes, leaf miners, grasshoppers, mites, and the onion maggot, and to be prone to leaf spot, downy mildew, black mold, and bacterial soft rot, among other things. But I’ve never had any of these problems and neither have any of the leek aficionados I spoke to—one of the reasons we agree that leeks are such a joy to grow. “We’ve had a problem in this area with phytoplasma,” Saunders says, referring to aster yellows disease, an enemy of some Allium crops. “Leafhoppers carry it in their mouths, and it was so warm they rode the thermals up from down south, spreading the disease. It destroyed a lot of garlic but didn’t touch the leeks or other onions. They’re tough.”
Originally published in Organic Gardening magazine, December 2013/January 2014