Spearmint grows just about anywhere indoors or out, keep it on-hand cold drinks and cocktails
A large pot is a good idea because the runners can really infest a garden bed and grow wild. This is great if you want lots of spearmint, but it can be a bad soil-mate. Hanging baskets can be a good idea in tight spaces.
Water regularly but it can handle some dryness.
Monthly fertiliser in pots and annual in the ground.