When to Plant Onions & Garlic in North Carolina

Whether you snip a dried garlic bulb from a braid or pull a sweet onion fresh from the soil, growing your own seasonings can provide a deep satisfaction. In addition to being easy to grow, onions (Allium cepa) and garlic (Allium sativum) have very few pest problems. They typically flourish in the well-drained cecil soil covering most of North Carolina, where gardeners plant onions in the spring and late summer and set garlic cloves in the soil each fall.

Spring onion seeds can be sown directly into well-prepared soil from Jan. 5 through March 31 for a fall harvest. With the state’s varying weather conditions, consider using soil temperature as your planting guide, sowing seeds when the soil warms to at least 50 degrees Fahrenheit. From Sept. 1 through 15, plant fall onion seeds for a spring harvest. Sow seeds 1/2-inch deep and 1 inch apart, thinning to 4 inches. Depending on the cultivar, onions take from 130 to 150 days to reach maturity. Cultivars recommended for North Carolina gardens include "Texas 1015," "Granex 33" and "Candy."

Starting as small, immature bulbs, onion sets can grow quickly when planted in well-drained soil in a sunny location. From Feb. 1 through March 15, put sets in the ground, staggering plantings every two weeks for an extended fall harvest. You have only a short window for a fall planting -- Sept. 1 through 15. Set the bottom of the bulb 1 to 1 1/2 inches deep, planting four to six bulbs per foot for a crop of medium-size onions, and two to four bulbs per foot for larger onions. Three cultivars recommended by North Carolina State University Cooperative Extension include "Ebenezer," "Excell" and "Early Grano."

Garlic needs at least two months at 32 to 50 degrees F to start forming bulbs, making it a fall crop across North Carolina. Gardeners in the western part of the state should set cloves in the ground in mid-September, while gardeners in the east should wait until November to plant. Set individual cloves in the soil, 1 to 2 inches deep, with the pointy end up. Allow 2 to 6 inches between rows. Amend the soil with at least 2 inches of compost, mulching with at least 2 to 4 inches of straw for additional winter protection. Recommended cultivars include "German Extra Hardy" and "New York White Neck."

The planting dates provided for onions are for the lower Piedmont and upper coastal plain, according to the North Carolina State University Cooperative Extension. If you live in the western part of the state, plant your spring onions 10 to 20 days later. Gardeners in eastern North Carolina can get their spring onions in the soil seven to 14 days earlier than the dates provided and plant fall onions and garlic seven to 10 days later.

In spite of all your careful planning, Mother Nature could still dish out a really late frost. Don’t worry -- a semi-hardy crop like onions can handle one or two lighter frosts (where temperatures drop to around 31 degrees F) and garlic is hardier still. If temperatures are predicted to drop lower than 31 degrees, however, provide protection to your onions. Hold in the soil’s natural warmth with a 2-inch layer of straw, leaves or grass clippings. Bed sheets, floating row covers and blankets all provide the same type of protection. As an added defense, water the soil one or two days before a harder frost; moist soil soaks up and retains more of the sun’s heat.