There are many differences between the various species, but the Mammillarias popular in the nursery are all very similar, with similar cultivation requirements.
They grow special tubercles, which make the plants look like clusters of conical warts. At the base you often find white fluff, whereas at the ends of the tubercles you will find various spines. The Mammillarias are grown in a very bright, possibly sunny location throughout the year. From May to September they should be watered when the soil is dry, but they can also withstand periods of prolonged drought.
In autumn and winter watering is suspended, and the plants are placed in a cold greenhouse, or at least in a place where temperatures do not drop too much. Growing them indoors often deprives us of the beautiful flowers in spring, and in Mammillarias they are definitely very eye-catching and pleasant.