Like most plants, garlic grows well in a fertile, organic-rich soil and requires proper sunlight for its growth and sustenance. While planting a garlic clove, make sure you plant it in an upright position, about an inch below the surface of the soil.
When planting individual cloves, do not plant very close and keep at least a gap of 3–5 inches between them so that they get enough space to grow well. Hence, with sufficient sunlight, nutrition, and water, the plant can grow quite easily.
Hence, once the plant has grown, you should start looking out for signs that may indicate it's time of harvesting. Since different garlic varieties and weather conditions have different harvesting times, the rule of thumb to be considered for harvesting garlic is to wait for the leaves to have a browning discoloration or the bulbs to grow to a proper size.
For this, simply loosen the dirt over one or two bulbs and while keeping them in ground, try to have an idea of their size. If the bulbs are large enough, this is the right time to harvest and if they are too small, it means they need more time to develop.
Do not pull the bulbs out, else you may end up having handful of tops, with no garlic bulbs. Rather, gently dig them out; freshly-dug bulbs are more prone to bruise if not handled carefully. Therefore, use a digging fork to loosen the soil and then dig out the garlic.