Most growers in Canada plant their garlic seed in October. We generally start anywhere from mid September and stop by mid- October.
If planted too late in the fall, the garlic will not start decent root growth until the following spring, which means they get off to a slower start. (rooting precedes sprouting and leaf growth).
Garlic an also be planted too early – too much top growth before winter can sometimes result in winter damage. However dont’ worry too much if you have some sprouting in the fall and then the leaves are killed by frost – Winter kill of garlic tnds to occur when both the clove and roots are suddenly frozen, not the leaves.
What size bulbs to plant: When choosing seed stock, a ‘happy medium’ is recommended. Judge seed by the size of the bulb, rather than each individual clove. Too hugely large and the chance of double cloves increases. Too small and your garlic will be small next year!