Vegetable Garden - Tips on Growing Leeks From Seed
A bowl of leek and potato soup on a chilly Autumn night is all the reason to grow leeks. Leeks are gentle on the digestive system. Besides being a vegetable plant that is easy to grow, they are frost hardy. They can stay fresh all winter long under a thick blanket of mulch. Leeks are a biennial member of the alliums, a tribe that includes onions, garlic, shallots, and chives. The white shank has a mild, almost sweet, onion flavor; the green tops are stronger tasting.
- Start seeds indoors 4-6 weeks before last frost.
- Seed Depth: In a warm, well-lighted area in February. Sow seeds ¼" deep in seed starting formula, keep evenly moist.
- Days to Germinate: Seedlings will emerge in 5-8 days.
- Temperature for Soil at Germination: will be at 75º F.(24º)C.
- Leek seed will do best when covered very lightly with soil.
USDA Hardiness Zone -First Frost Date- Last Frost Date
- Zone 1 -July 15th -June 15th
- Zone 2 -August 15th- May 15th
- Zone 3 -September 15th May 15th
- Zone 4 -September 15th May 15th
- Zone 5 -October 15th April 15th
- Zone 6 -October 15th April 15th
- Zone 7 -October 15th April 15th
- Zone 8 -November 15th March 15th
- Zone 9 -December 15th February 15th
- Zone 10 -December 15th January 31st (sometimes earlier)
- Zone 11 -No frost. No frost.
OUTDOOR SOWING NOT RECOMMENDED
- TRANSPLANT: Seedlings outside 2-3 weeks before your last frost date, or when soil can be worked.
- Remove the leek seedling from the growing flat, gently teasing the roots apart with your fingers.
- Trim the roots to about 2 inches.
- By using a hoe, dig a trench about 8 inches deep. Set the leeks in the trench, spacing them 6 inches apart. Fill the trenches with soil and press it firmly and yet gently in place.
- Mulch the plants with grass clippings.
- As the leeks begin to grow, mound the soil up around their base. This is a traditional way to aid in the bleaching and sweetness of the stems.
- Set plants 2"apart in rows 12-18" apart.
- pH range of 6.0-7.5
- Temperature for soil for growing: 60ºF (16º)C.
- Spacing: should be 6” in rows, 3 rows to a bed.
- Watering: Moderate.
- Light: Full sun will give you the best yields, but will tolerate partial shade.
- Nutrient requirements: N = Moderate, P =Moderate, K = Moderate.
Avoid following onions, shallots, garlic and chives.
- Good Companions: Bush bean, beet, carrot, celery, garlic, onion, parsley and tomato.
- Bad Companions: Pole bean and pea.
- Water deeply once a week in dry weather.
- Unlike onions, leeks do not produce bulbs, but stash their flavor in thick, juicy stems, looking similar to a giant scallion. Leafy stems are eye-catching and demand little elbowroom in the garden.
- In the supermarket, leeks can cost a premium; however if harvested from the garden, the trouble-free stems dish up flavor for a negligent fee. Leeks are most famous for starring in pea, and leek -potato soup, but they also hold their own when steamed like asparagus, oven-roasted, chopped in quiche, or wrapped in ham, baked, and covered with cheese sauce.
- Frost-tolerant leeks thrive in cool weather. In Zones 7 and warmer, plants can over winter in the ground, perfect for fall planting. In northerly zones, tuck plants into beds in early spring, as soon as soil can be worked.
- Soil that tumbles into leaf folds can wind up trapped between skin layers in the stem. To keep this from happening you can slip a section of paper tube, such as from toilet tissue or paper towels, over the plants while they are still young as early as planting time. The tube will rot over the growing season, but will help prevent soil from getting into leaf bases during early growth.
- On young plants, slugs can be devastating. Gather them at night, set traps, or use biological control. If there is a lot of rain in winter or early spring, leaf rot can set in. Rot shows as white spots on leaf tips that eventually shrivel. At this point there is not much you can do except pull the rotted plants and thin the planting to increase air circulation.
- In summer, orange pustules on leaves indicate leek rust, which is worse in wet growing seasons. Remove affected foliage; later maturing foliage will be healthy.