How long it takes for garlic (Allium sativum) to grow and mature depends on when you plant the cloves. Garlic grows best when it experiences a period of chilling. The best time for planting garlic is fall, and fall-planted garlic matures in about eight months. Garlic can also be planted in spring, and spring-planted garlic takes less than eight months to mature, but it may not form bulbs. Garlic grows in U.S. Department of Agriculture plant hardiness zones 4 through 9.
A spot in full sun and well-drained, fertile soil provide the best growing conditions for garlic. Choose a part of the garden that gets at least eight hours of sun each day. Garlic tolerates alkaline soil, but it prefers acidic soil that's slightly dry and rich in organic matter. Don't grow garlic in heavy, wet soil because this leads to rot.
Space garlic cloves 4 to 6 inches apart in rows 15 to 24 inches apart. Don't grow garlic on a site where it grew during the past three years, to help prevent disease problems.
Keeping garlic well-watered and mulched through the growing season provides the best bulbs. Mulches suppress weeds that compete with garlic for water, and also help conserve soil moisture.
Water garlic every eight to 10 days in dry weather, moistening the soil to a depth of 2 feet. Spread a 2-inch layer of garden compost, well-rotted manure, leaf mold or other organic matter around the garlic plants, but don't allow the mulch to touch the garlic plants' leaves.
Fall-planted garlic needs a high-nitrogen fertilizer in spring, and garlic planted in fall or spring needs fertilizer in early summer. Ready-to-use 12-0-0 blood meal supplies garlic nutrient needs.
Put on gloves, and evenly sprinkle ready-to-use 12-0-0 blood meal at a rate of 1 tablespoon per 1 square foot over a fall-planted garlic bed when the garlic begins actively growing in spring. Water the granules into the soil. Apply the fertilizer at the same rate to fall-planted and spring-planted garlic two to three months later, in early summer. Manufacturers' instructions vary among products, so read the fertilizer label and follow the instructions.
Harvesting and Curing Garlic
Curing garlic after harvest helps prevent it from spoiling in storage. Garlic is ready for harvesting when the bulbs contain well-developed cloves and the bulb skin is thick, dry and papery. Other signs of maturity include brown leaves and only six to eight green leaves remaining on each plant. Don't wait longer than two weeks after all the leaves have withered to harvest garlic, because the bulbs deteriorate in the soil. Push a garden fork into the soil 2 inches from the base of the plant, and lever the bulb out of the soil.
Spread garlic bulbs, with the leaves attached, in a single layer in a warm, shady, dry, airy place. Don't allow the bulbs to touch. After three or four days the bulbs and leaves will be dried out and ready for storage. Store garlic in a dry, shady place at temperatures between 40 and 60 degrees Fahrenheit.