Good question! I plant always from existing cloves, breaking open my sorted "planters" bulbs from the obvious "eaters", planters being the best looking as far as outside wrapper quality and individual clove size. These planters are carefully broken apart to separate the cloves where only the largest cloves are then planted. In a bulb of 6-8 cloves of the selected planters, maybe 3-4 cloves of each will be planted, the rest go back into the eater pile.
Plant cloves 6 inches apart around mid to late October for me, they need to just begin rooting before the frost puts them on hold for the winter. The winter is necessary for hard neck variety garlics, as the dormancy period is part of their life cycle. They will be forst up in very early spring and 6 inches tall before you plant anything else...they are that early!
Now, to confuse things, I am in the process of growing from seed of my own, which is not really a seed but called a bulbil. When the garlic flowers in the early summer, inside are what are called bulbils. These look like seeds but are not, they are clones of the single parent. Plant a bulbil in late fall and it comes up the first year as a tiny looking blade of grass, but with a pea sized single garlic clove in the ground (which will be harvested in a week or so). This needs to be planted again in the fall, where year 2, it will be a half size clove sometime single, sometime multiple cloves. Split if necessary and plant again in fall. Now you are 3 years in, and in regular garlic harvest you will end up with a bigger bulb then you had started with 3 years ago...it's a way to rejuvenate the genetics.
Hope that answers!!!