Some growers do mulch their garlic at the time of planting in the fall. The mulch is applied after the weather turns cold and the mulch is removed as early as possible in the springtime. The downside is that if the mulch is frozen to the ground it is difficult to remove it in time for the soil to start warming up as early as unmulched soil. Unmulched ground is subject to alternate freezing and thawing which can heave the garlic seed out of the ground. However, unmulched soil warms up more quickly than mulched soil giving plants a longer growing season in which to mature.
Straw is the mulch of choice for most growers.
Uniform soil moisture is very important during the growing season. If it is dry then the garlic must be watered in order to perform well. Discontinue watering by the first of July as harvest usually occurs two weeks later. Too much water at harvest time, promotes disease problems. During the spring and early summer, garlic needs nitrogen.