When to Plant Leeks in North Carolina

Temperatures

• Plant leeks from seed when the ground temperature reaches at least 45 degrees Fahrenheit. The seed will germinate at up to 95 degrees Fahrenheit, with best results at about 77 degrees Fahrenheit, according to Cornell University Cooperative Extension Master Gardeners. Since leeks are extremely frost-tolerant, they will winter over well, so you do not need to rush to harvest before fall frost, which can come to North Carolina between late September and late December.

Spring

• Leeks' growing season can take as long as five months, so many gardeners plant the seeds eight to 12 weeks before last frost, which can occur from mid-March through late May in North Carolina, depending on the growing region. You can plant the spring crop as soon as the ground dries out enough to avoid soggy, muddy soil, but it does not have to completely thaw first. Spread a 2-inch law of hay or straw mulch over the top of your planting area. North Carolina Cooperative Extension Pender County Center advises that the spring planting time for leeks runs from mid-February to the end of June. The early starts would be available to harvest in early summer, while the late starts would be ready in mid-fall.

Fall

• The Pender County Center explains that leeks' hardy nature make them good candidates for a cold-weather garden planted in late summer. Sow the seeds directly outdoors from mid- to late August. This crop should be ready to harvest in December to January.

Wild Leeks

• Wild leeks (Allium tricoccum or Allium tricoccum var. burdickii), known as ramps, have been gaining popularity in fine-dining restaurants, reports the North Carolina University Cooperative Extension Service, thereby increasing the demand for this delicacy to the point that it is difficult to maintain consistent supplies of naturally grown specimens. Therefore, they encourage the cultivation of wild leeks to conserve the natural habitats where they grow while meeting consumer demand. You can plant the ramp seeds under a patch of beech, birch, sugar maple, poplar, buckeye, linden, hickory or oak trees in late summer to early fall before the soil freezes. The Extension Service explains, "Ramp seeds can take 6 to 18 months to germinate" due to variations in the warm-cold cycle that affect when the seed will break root and shoot dormancy. If transplanting young starts, they recommend doing so in mid-March.