IMO the hardest part of growing garlic is waiting for harvest when you get to this point in the year.
Is the rule of thumb, three weeks after scapes? I have to look it up every year, itching to pull em.
PH, in our climate here which often turns wetter in August after a dry July, I found that my leaves were not drying down on schedule. I had dry tips but not dry leaves. An experienced grower here who is in a similar if not wetter environment next to a pond, advised me to count the dry tips as dry leaves for harvest purposes, if the season is wet they just stay green at the bottom. So for us, counting weeks from scapes and checking bulb size is more important than the number of fully dry leaves or the state of the tops.
OTOH at the farm which is upland and a hillside situation, leaves are dryer at harvest time than they would ever be in my garden. It is a benefit I suppose to the drying and curing process, if the tops are partly dried down already. But also she lets them go longer which is necessary for your maximum size crop, too.
