If you live in a warm climate, this reference should be a good guide. It is the FAQ for the Heirloom Garlic Archive, which maintained & observed all of SSE's collection. Halfway down the page, it gives harvest dates for the different garlic types in New Mexico. It also describes how many leaves should still be green (and how many brown) for each garlic type, at the proper stage for harvest. Heirloom Garlic Archive

If you leave garlic in the ground too long, the bulb wrapper will disintegrate, and the exposed cloves will keep poorly. This generally will happen if all of the leaves are allowed to turn brown before the garlic is dug. Also, if you notice tiny new small leaves sprouting from the stalk - whether the leaves have died back or not - then the cloves are dividing, and the garlic should be dug immediately. I've observed this phenomenon when there was heavy rainfall close to harvest time.

Late May, June or early July.

Zeedman shared an excellent link.. And yep, it will really depend on just what kind of garlic it is.

Like for me, I'm in zone 6, and I grow several different kinds of garlic. Pulling them can start as early as late June, main pulling is in July and some can stretch as late as early August.

I've read that for hardnecks, a month after scapes form. I noticed the begining of scapes on my Metechi , here near N Cal'sCal's central valley. Heat speeds up the process, so I am always praying they will keep growing until June.

I take some garlic for cooking by mid July here in Minnesota. Then I watch for the bottom third of the leaves to dry up to complete the harvest, which varies from type to type. Better a little soon rather than too late. The curing process is far more important and even relatively green bulbs that have at least bulbed up will cure pretty well, if you are careful, although you may have to wait longer for the stems and leaves to dry off properly. In Cal's Central Valley, I would GUESS that you could do some harvesting in May, June for sure and probably early June at that.

With hardnecks, I count 21 days after full scape and dig a sample head. With softnecks, I want to see 9 leaves, with the bottom three withering. In your climate this will probably happen in late May or early June. Here in 6b it's around the first of July.

thanks everyone! I looked at my packaging and it says "French". I got it from wegrowgarlic.com but can't now find whether that's a hardneck or soft neck. Any ideas?