The secret to a harvest of large garlic bulbs is fall planting- generally 4-6 weeks before the soil freezes, or as late as the beginning of December in mild-winter regions. This way the roots can become established before winter sets in and will be ready to support vigorous leafy growth come early spring. It also makes for larger plants and therefore larger bulbs. The plants will begin to produce bulbs once the long days of June arrive.
Step 1. Prepare the Planting Bed
It is best to plant garlic in a sunny spot not recently used for garlic or other plants in the onion family. As in the case with most vegetables, rotating crops prevents the buildup of disease organisms in the soil. Garlic requires a reasonably fertile well-drained soil with a PH of 5.5-7.0. Avoid planting in areas where water can collect around the roots, causing them to rot or become diseased. Planting in a raised bed works well. Work several inches of compost or well-rotted manure into the bed, plus a complete fertilizer such as 10-10-10. Then smooth the soil with a rake.
Step 2. Plant and Mulch
Garlic reproduces vegetatively- that is, it grows from individual cloves broken off from a whole bulb. Each clove multiplies in the ground, forming a new bulb that can consist of 10 to 20 cloves. Break a bulb apart into individual cloves, keeping only the largest, firmest ones for planting. Space the cloves four to six inches apart and allow about a foot between rows. Be sure to set the cloves in with the pointed end up and the flat basal plate down. Push each one an inch or so into the ground, firm the soil around it, and water the bed if it is dry.
After planting, lay down a protective mulch of chopped leaves, straw or grass clippings. In cold-winter regions, the mulch should be four to six inches thick to prevent the roots from being heaved out of the soil by alternate freezing and thawing. A lighter mulch is useful in milder climates, where it slows the growth of winter weeds. Don’t worry if a few garlic leaves sprout; most of the plant’s above ground growth will occur in spring.
Step 3. Spring Care
When the leaves begin to grow in earnest, it’s important to feed the plants again to encourage robust growth. Apply a high-nitrogen fertilizer that decomposes slowly, such as blood meal or bone meal, gently working a teaspoon or two into the soil near each plant.
If the mulch has decomposed, apply another layer to reduce weeds and to help retain moisture. Pull any weeds that do appear, or they will rob moisture and nutrients from the garlic. And be sure to keep the garlic patch watered during dry spells.
In late spring some varieties send up flower stalks that will eventually produce small bulbils. Cut these stalks off (you can sauté them or add them to salads and vegetable dishes if you wish).
Around the middle of June, garlic will stop producing new leaves and begin to form bulbs. Remove any remaining mulch and stop watering. The garlic will store better if the soil around the maturing bulbs is allowed to dry out.
Step 4. Harvesting and Storing
When most of the leaves have turned brown, gently pull or dig up the bulbs. Take extra care not to bruise the bulbs. Avoid leaving them in the ground too long or they will separate and not store well. Lay the plants, leaves and all, out to dry for 2-3 weeks in a shady spot with good air circulation. When the roots fell dry and brittle, rub them off, along with any loose dirt. Don’t wash the bulbs or break them apart or the plants won’t last as long.
Braid the garlic, tie it in bunches or cut off the stems a few inches above the bulbs. Hand the braids or store the loose bulbs on a screen in an airy, cool (but not freezing) location. Set aside the largest bulbs to replant later in the fall. Check your harvest often during the winter and promptly use any bulbs that show signs of sprouting.