Start your mint seeds indoors to help them properly germinate. Plant the seeds in a flat or a small container in the late winter, about six or seven weeks before the final frost is expected. Sow the seeds a couple inches below the soil and water them thoroughly. Continue watering the seeds, but only after the top of the soil has dried out. Place your seed containers near a sunny window.
Once your seedling has matured and the threat of frost has passed, plant your seeds outdoors. Place your mint seedlings in a moist area that receives partial shade. Space each seedling about 12 inches to 18 inches apart, as these plants can get quite big. Plant the seedling in the ground up to its bottom leaves.
Mint prefers growing in a moist environment, so water the soil often enough that it stays moist. However, do not water so often that the ground is boggy. While mint will still grow if it does not receive enough water, its growth will be extremely stunted.
Once you get your mint plants going, be aware that the herb spreads easily and can take over the garden. You will likely have to prune new plants that begin coming in by pulling them up by the roots. Different varieties of mint plants also cross-pollinate easily, so keep them far apart. Consider picking the buds off of your mint plants before the flowers appear so that no seeds can spread.