The other day I was shopping for leeks at the Orleans farmers’ market. I noticed that some vendors had leeks with a lot of green on the stems and others had leeks with more white. Peter Fossel runs Swan River Farm in Dennisport and knows a lot about leeks. He’s something of a gardening guru—he wrote the book Organic Farming: Everything You Need to Know, and is the former editor of Country Journal.
Here’s what Peter told me about how to grow a leek with a long white stem: “It depends on how deeply you blanch them. We blanched them about 6 inches, maybe 8 inches deep last year. The higher you pile the mulch, anything under that will be white, and that’s the tastiest part. All parts of the leek can be eaten, but the white part is the tastiest.”
Blanching is a fairly common growing technique. Farmers blanch celery, endive, asparagus, and even rhubarb, lettuce, and cabbage sometimes. The basic idea is to prevent photosynthesis by blocking sunlight, so that the plant doesn’t produce chlorophyll.
“Once the seedling is fairly sturdy, I don’t pile it up with dirt,” Peter explained. “I pile it up with leaves or straw.”
And why leaves or straw?
“Because it will prevent the ground from freezing,” he said. “If you pile it up with dirt— you can do that, but chances are higher that the ground will freeze and it will make the leek into mush.”
I asked him when he planted his leeks.
“These I planted last year and wintered over. Even in a cold winter with a little mulch they’ll do fine, and they actually grew between last fall and today.”
Peter says you can harvest leeks anytime between late summer and early spring. He likes to wait until they’re at least an inch in diameter and have about 6 to 8 inches of blanched stem.
“You have to have patience,” he cautioned. “They grow slowly. The ones I planted this winter—inside, in flats—they’re only about 6 or 8 inches tall right now.”
Peter plants the variety King Richard every year. It’s an heirloom, and he likes it because it responds well to blanching. The leeks he’s selling have long, straight, white stems and he says this makes them easy to clean and gives them excellent flavor.
Peter likes to cook his leeks down in soups and stews. I ate mine in a butternut squash and shrimp bisque.
“I think leeks are the most delicately flavored member of the onion family that there is,” he said. “They’re wonderful.”