Garlic has very particular temperature needs, to form bulbs, but you can easily have a steady supply of garlic tops, or greens that can be used instead of scallions. You don’t need a large container for garlic sprouts. A depth of about 4 inches should suffice. Simply plant the individual cloves about 1 inch deep and water regularly. The cloves should sprout in about 1 week.
Let them grow to 8 – 10 inches before you begin harvesting.
Cut off what you need and leave the rest. You generally only get one flush of growth from each clove. They may sprout again, but the quality declines, so start new cloves when you begin harvesting the current crop.