Unlike other varieties in the Allium genus, garlic doesn't bulge from the ground when it is ready for harvest. Instead we give garlic time and watch for changes in the leaves.
Last fall, late in the season, I planted approximately 30 garlic cloves of 'Music' a hardy soft-neck variety. I waited about 8 months until the lower leaves began to die back, and then I stopped irrigating the crop. For approximately a week, the crop was left to dry. As the week progressed the long leaves browned, bending away from the twisting scape. This drying in the soil is part of the process of curing garlic.
Next, the harvest. I used a garden fork, inserting it a few inches away from the stalk, pushing it down and then bringing it up, underneath the garlic head. The fork allows much of the dried soil to fall away.
It is important to remember not to attempt to wash or scrub as the intact skins are necessary for long term storage. For the next step I laid out each garlic head (roots and stalks attached) in a single layer in a place where they could continue to dry that was cool and shady. After 3-4 weeks I trim off the roots and cut the stalks. The remaining dirt is then gently brushed off.
Are you thinking you want to give garlic a try? If so, it is a great time to prepare the bed and amend the soil. Garlic can be planted between September and November, depending on the zone and the weather. You can also plant garlic in the spring but the yields are higher with a fall planting, and you can use that space in the garden for growing other things.
Learn more at: http://sfp.ucdavis.edu/pubs/SFNews/archives/95071/
And Garden Betty has great close-up pictures and ideas: https://www.gardenbetty.com/a-guide-to-curing-and-storing-garlic/