For example, an African violet would grow better in potting soil containing extra peat moss, while a cactus requires sharp (i.e. plenty of) drainage, most commonly perlite or sand.
My houseplants are species such as African violets and orchids, which the cats leave alone: no philodendrons, dieffenbachia, parlour palms or other risky houseplants are allowed.
Fruit grown by exhibitors will be in the competition, as well as a section for all types of container plants (with houseplants such as African violets, geraniums or cactus).