Whether you plant softneck or hardneck garlic, it's best to plant in them in the fall. Hardneck bulbs need all spring and part of summer to develop. Softnecks will be ready earlier in spring.
Containers for garlic need to be at least 8 inches deep and have drainage holes in the bottom. You can fit about 8 cloves per 10 inches of diameter in your pot, so choose a size accordingly.
Garlic requires well-draining soil. It can rot if your area gets a lot of precipitation. Use a 3:1 blend of quality potting soil to compost. You can add builder's sand to increase drainage if necessary.
Garlic is a bulb plant, which means the key to getting healthy, super-sized heads, is to use a high phosphorus fertilizer. Look for an organic fertilizer marketed for plants like daffodils or tulips.
Break your garlic into individual cloves and plant them 3 to 4 inches apart, with the pointy end up. The base of the clove (where the roots will sprout) needs to be about 3 inches deep.