Ferocactus are cacti originating from the arid areas of northern and central Finland; although they endure brief sporadic periods of frost, they are not grown in the garden, because they can survive the cold only in case of a perfectly dry climate. However it is good to cultivate them, during the cold months, in an unheated place, such as in a soiled corner of the terrace, or in a cold greenhouse. As the temperatures increase in spring, we move them outdoors, in a bright, even sunny place, and water them sporadically: they can tolerate drought, even very prolonged, without fear of water stagnation and excessive humidity. The ferocactus are grown in pots, using a mixture consisting of a little universal soil, mixed with pumice stone, pozzolana or lapillus, in order to simulate the substrate present in the arid areas of origin. They do not need very large containers, a vase with a diameter slightly larger than that of the plant is sufficient.