Leeks Stretch the Harvest Well Into Winter

While growing, the leek resembles a flat-leafed onion. However, it produces a thick, white stem instead of a bulb. Under ideal conditions, that stem may grow to two inches thick and ten inches tall, with plenty of healthy, green leaves above it.

A relative of the onion, leeks have long been a staple in European gardens. They’re the main ingredient in vichyssoise, the chilled potato and leek soup. They’re also good prepared any way onions can be used – in salads, casseroles, soups, stews, or even sauteed and served as a side dish. The flavor is milder and sweeter than most onions, and they’re easier to store if you have an empty hole in the garden.

Leeks will last about three weeks in the refrigerator. Those grown in home gardens can be left in the ground and harvested all winter. Simply cover them with a light layer of straw, leaves, or similar materials, then dig them when needed. Those not harvested over the course of the winter will resume growth in the spring. These few leftover leeks don’t get appreciably larger the second year, and they can be a bit tougher. However, the second year plants produce seed. Although many gardeners prefer to use fresh, hybrid seed each year for leeks, the volunteer seedlings that do appear make tasty additions to the salad bowl.

Growing Leeks From Seed

Leeks can be started directly in the garden, but don’t expect them to be ready to harvest until late in the season or next year. To get the thick stems that you see in the grocery stores, you should plant seedlings in the garden instead of sowing seed. However, leek seedlings may be difficult to locate at local garden centers, so ask early or be prepared to start them from seed.

To do so, start the seeds indoors in February. Sprinkle them over the top of a small pot filled with potting soil or a seed-starting mix. Cover with a light dusting of soil, and water from the bottom. Cover the pot with a plastic bag and tuck the ends under the bottom to form a miniature greenhouse. This prevents the soil surface from drying out. Remove the bag after the seedlings have sprouted.

Place the pot in a south or west-facing window, and don’t forget to open the curtains daily, or grow under fluorescent lights. Repotting won’t be necessary. However, as the seedlings grow, you may need to trim the tops to about four inches in height to keep them from toppling over or tangling in the pot. This also will encourage better root growth and thicker stems, which makes transplanting in the garden easier.

Leeks can be planted in the garden from five weeks before the last frost until two weeks after. Around here, that means from early March to late April. The seedlings are very cold-hardy, so long as they’re hardened off properly. Don’t move them directly from a 70-degree house to a 40-degree garden. Put them in a cold room for a couple of days or in a sheltered spot outdoors for several hours a day for a week or two. Or if you have a cold frame, place them there about a week before you intend to plant them. This gives them time to adjust to the temperature change and the brighter outdoor light.

Space seedlings about six inches apart in either trenches or raised beds. After the plants are as thick as a finger, begin filling in the trench (or mounding the dirt around the stems if you’re using a raised bed). Never fill in more than an inch at a time, or cover the point where the leaves begin to branch from the stems. This can cause the plant to rot. Weed carefully, especially early in the season. Keep the soil moist, but not soggy.

Harvesting

Leeks can be harvested anytime after they reach an inch in diameter. Any thinnings from the row can be tossed into a salad, but aren’t much good for most recipes. Although the mature leek may be pulled by hand, digging with a spade or fork may be easier and result in less damage to the stem if the soil is hard.

After harvest, store in the refrigerator or freezer until needed. Or mulch them in their growing beds and delay harvest until they’re needed in the kitchen.