Garlic cloves purchased for planting or from the grocery store may sprout before you have a chance to use or plant them. While it's best to plant garlic before it sprouts, you can also plant those first beginning to send out shoots depending on the time of year. When planted properly, garlic plants produce full-sized bulbs for harvest in midsummer.
Garlic cloves that begin sprouting in fall have a chance to grow well, since fall provides the best time for growing. Those that sprout earlier usually go to seed before they produce usable bulbs of an adequate size. Planting should occur before the cloves sprout, but newly sprouted cloves usually grow fine if planted as soon as the sprouts begin emerging from the individual cloves. Sowing cloves four to six weeks before the first expected fall frost gives the plants time to establish roots before the ground freezes.
Garlic bulbs develop best in well-drained soils, since overly wet conditions may lead to rot. Working a 5-10-10 fertiliser blend and compost into the bed prior to planting helps improve the nutrition in the bed so the sprouted garlic continues to grow well. Dense soils cause bulbs to form poorly, but tilling and breaking up the top 8 inches of the bed provides a finer soil bed for the bulbs to develop in.
Planting the Bulbs
Garlic bulbs consist of multiple cloves surrounded by a papery skin. Once broken apart, the larger outside cloves grow into usable bulbs while the smaller interior bulbs are best used for cooking. The top of the clove sits 1 to 2 inches beneath the soil surface with the sprouted end facing upward when planted properly. A spacing of 6 inches between cloves gives the plants the room they need for bulb and root development.
Garlic doesn't develop well in dry soils, so regular watering helps grow large, healthy bulbs. Soils need to remain evenly moist, so weekly watering is necessary in fall until the ground begins to freeze. Regular irrigation resumes in spring as the ground thaws. Applying a thick mulch cover of straw in fall just as the ground begins to freeze helps insulate the garlic plants and protects the tender sprouts from winter cold.