Garlic does not produce a true seed and, therefore, is multiplied vegetatively from cloves. It grows well in many soils and climates, but only varieties that are hardy and adapted to the Northeast will perform well here. Supermarket varieties grown in warmer climates with longer growing seasons usually do not grow well in this area. It is something of a challenge to obtain appropriate planting stock from commercial sources. The most promising source of well-adapted varieties is likely to be other growers in your area. If ordering varieties from out of the region, start on a small scale and evaluate their performance.

Topset garlic sends up a flower stalk called a scape and has bulbs with few, large cloves. Softneck garlic does not produce a scape, and the bulbs contain more numerous, smaller cloves. Rocambole is a topset type that has a curved scape. Elephant garlic, a member of the leek species, produces large bulbs with very few cloves.

Planting

Garlic is planted in the fall to allow enough time to develop roots but not to emerge from the soil. In most areas, this calls for planting in October. To prevent winter injury and heaving of cloves from the soil, plantings should be heavily mulched with straw until early spring, or planted deeply. Spring-planted garlic requires a cold treatment of 40°F for two months to induce bulbing and will not usually size-up as well as fall plantings.

Space garlic cloves from 4” to 6” apart in the row, with rows 18” to 24” apart, or in rows that accommodate cultivation equipment. Some growers plant in beds through black plastic after making holes large enough for the garlic to emerge through. Plant 1” to 2” deep if straw mulch will be applied; otherwise plant 3” to 4” deep. Orient the clove root-side down. Do not plant cloves that appear to be diseased.

Large cloves tend to produce large bulbs. When saving cloves, select the largest bulbs, and and screen them carefully before planting planting so that only those that show no signs of injury or disease ane used.

Heavily mulching may garlic plantings increase susceptibility to bulb diseases in wet springs. Under these conditions it is advisable to pull the straw back off the crop to allow the soil to dry. 

Lime

Soil pH should be maintained in the range of 6.2 to 7.0.

Fertility

Follow soil test P and K recommendations for onions. Without a soil test, garlic is generally fertilized with N-P-K in a 1-2-2 ratio. Apply about 40 lb/A of preplant nitrogen and a single N sidedressing of about 30 lb/A when tops are about 6” high.

Irrigation

After planting in the fall, irrigation is not normally needed so long as soils are not unusually dry.   In the spring, garlic is very sensitive to dry conditions due to its shallow root system. Lack of irrigation in a dry growing season will result in smaller bulbs, especially if mulch is not available to retain soil moisture.  To minimize diseases, the crop should not be irrigated within a couple weeks of harvest. 

Harvest

The scapes of topset and elephant garlic should be removed as soon as they appear in May or June to retain the plant’s resources for bulb formation. However, under optimal growing conditions, leaving the scapes on may not significantly reduces yield. Note that the scapes are edible and can be used as a spicy vegetable suitable for stir frying.

Harvest when about half the leaves have turned yellow in July. The ideal timing attains maximum bulb size but does not allow the cloves to begin to separate. Waiting too long to harvest results in separated bulbs that sell and store poorly. Test dig a few bulbs before digging the entire crop. Softneck types will mature a few weeks earlier than topsets.

Undercut the bulbs to facilitate removal from the soil. Pull shoots, bulbs and roots and allow plants to air-dry where they are protected from the sun, which may scald the bulbs. A well-ventilated barn is ideal. Thorough drying for 3 to 4 weeks is essential for good storage.

Once cured, rub or brush soil off bulbs, and braid or remove tops, clipping them about 1 inch above the bulb and trimming the roots off. 

From USDA Handbook 66: Garlic for seed purposes should not be stored under refrigeration. Optimum storage temperature for garlic for seed is 50^oF with a relative humidity of 65-70%. Garlic cloves sprout most rapidly between 40 and 50^oF, hence prolonged storage at this temperature range should be avoided.  Storage of planting stock at temperatures below 40^oF results in rough bulbs, side-shoot sprouting (witches-brooming) and early maturity, while storage above 65^oF results in delayed sprouting and late maturity.

Store other garlic at 32^oF and 65 to 70% relative humidity.  If in good condidtion and well cured when stored, garlic should keep for 6 to 7 months at 32⁰F. Relative humidity should be lower than for most vegetables because high humidity causes root and mold growth.