Melocactus are cacti originating in Central and South America; about thirty species belong to the genus, with a globular stem, characterized by areolas with large arched spines and a particular formation placed on the apex of the plants, called cephalic, similar to a turban of thin grayish, pink or reddish hairs; the name Melocactus derives from the cephalic, which looks like an apple placed on plants. Cephalium does not characterize young plants, as it takes a few years to form; the Melocactus they have very slow development, and it often happens to find specimens grafted on more rapidly developing cacti, such as trichocereus. They produce colorful flowers, which bloom from the mullet, followed by small red fruits.
Melocactus are difficult to grow plants, suitable for cacti cultivation experts, and not recommended for beginners. They do not produce basal suckers, therefore all the specimens that we find in the nursery are produced from seed, and have a few years of life; for this reason, in addition to being difficult to grow, melocactus is also expensive, an additional reason to leave these plants in the hands of expert growers.
The Melocactus, as we said, are quite difficult to grow, as they need high temperatures all year round, low humidity and high brightness. In summer they do not like full sun, especially if placed outdoors, so we will find a place in partial shade, very bright but characterized by a few hours of direct sunlight, and possibly it will be the coolest hours of the day. In winter they need temperatures above 10-12 ° C, therefore they are grown in a tempered greenhouse or at home, but always in a very bright place, even in full sun, which being low on the horizon will not risk burning the epidermis of the stems .
The watering must be parked, to be provided only when the soil is dry; during the winter months we will water only sporadically, with small quantities of water, while in the summer we can water about once a week, avoiding to supply water if it has rained, or if the soil is still damp. We always avoid wetting the cephalium, which otherwise is affected by mold and fungi.
Melocactus have a fairly wide and deep root system (compared to that of other cacti), for this reason they are generally not grown in common pots for cacti, which are decidedly very small; instead, they are planted in large bowls, so that the roots can find all the space they need. The substrate must be very porous, consisting of universal soil, mixed with pumice, lapillus or pozzolan stone, or with any material useful to simulate a rocky and very permeable soil; if grown in unsuitable soil, melocactus tend to get sick easily, in a short time. The fertilizations are provided only in the vegetative period, from April to September, about once a month; we always use a fertilizer for succulent plants, avoiding other types of fertilizers, which contain excessive quantities of nitrogen, harmful to the cacti.