Reserve a spot in your garden for onions and their milder cousins, leeks. Their flavor melds wonderfully in all sorts of dishes, from soups and salads to main entrées. Listen to learn how to grow these underground wonders so that you’ll have a plentiful supply. This segment of The Old Farmer’s Almanac Garden Musings podcast series was written by George and Becky Lohmiller and is read by Heidi Stonehill, an Almanac editor.
Onions are one of the most widely cultivated vegetables in the world. In ancient times, they were a dietary staple because they are easy to grow and can be stored for a long time.
Onions do best when started in cool (not cold) weather. In cold-winter areas, plant onions in spring. In mild areas, you can plant them in fall or winter.
Onions can be raised from seeds in areas with a long growing season, but most gardeners prefer to plant onion sets—tiny onions that were started from seeds the previous season. To grow large onions, plant the sets four to five inches apart in a row or bed. If you love scallions, or green onions, plant the sets closer together and harvest these immature onions as you thin the plants.
Onions grow best in rich, loamy, well-drained soil. Improve sandy or clay soil with compost or peat moss, and add a standard application of fertilizer before planting. A light application of mulch will help keep the weeds down and conserve soil moisture.
Leeks are closely related to onions, but they don’t have a bulb. Instead, leeks form a thick, fleshy stem at the base of their coarse leaves. The cultural requirements for leeks are the same as for onions. In northern areas, start leeks indoors in flats. When the plants are six to eight inches tall, cut them back to three inches and transplant them to the garden. Mound the soil as they grow, so the lower five inches of stem will become blanched; or plant the leeks in a trench five inches deep and fill it as the plants mature. As with onions, leeks can be harvested when they are young, or you can leave them in the ground until frost. If mulched with a heavy cover of hay, leeks can be harvested well into the winter.
Why the crying? The pungent odor released when an onion is cut is caused by allyl, a natural sulfurous oil that quickly vaporizes and can bring a person to tears. Plunging an onion into boiling water for a few seconds before you peel it will neutralize the allyl, or you can peel it under running water to dilute the irritant—with wet hands and dry eyes.