A houseplant is a plant that is grown indoors in places such as residences and offices, namely for decorative purposes, but studies have also shown them to have positive psychological effects. They also help with indoor air purification, since some species, and the soil-dwelling microbes associated with them, reduce indoor air pollution by absorbing volatile organic compounds including benzene, formaldehyde, and trichloroethylene. While generally toxic to humans, such pollutants are absorbed by the plant and its soil-dwelling microbes without harm. Common houseplants are usually tropical or semi-tropical epiphytes, succulents or cacti. Houseplants need the correct moisture, light levels, soil mixture, temperature, and humidity . As well, houseplants need the proper fertilizer and correct-sized pots. (Link to Wikipedia)