Mint is one of the easiest and fastest herbs to grow. Since their roots spread so quickly and are incredibly invasive, make sure you plant them in their own space or give them a foot and a half between other herbs or plants.
Bright, indirect light (indoor) or partial shade (outdoor). Harvest before the plant flowers.
Pro-tip: Unlike other herbs, spearmint can be sensitive to direct sunlight and heat sources. Pinch back flower buds when you see them to extend the harvest period.