The Melocactus are cacti originating in Central and South America; about thirty species belong to the genus, with a globose stem, characterized by areolas with large arched spines and a particular formation placed on the apex of plants, called cephalium, similar to a turban of thin greyish, rosy or reddish hairs; the name Melocactus it derives from the cephalium, which looks like an apple placed on plants. The cephalia does not characterize young plants, as it takes a few years to form; the Melocactus they have a very slow development, and it is often possible to find specimens grafted onto cactaceae with faster development, such as the trichocereus. They produce colorful flowers, which bloom from mullet, followed by small red fruits.
The Melocactus are plants of difficult cultivation, suitable for experts in cultivation of cacti, and not recommended for beginners. They do not produce basal shoots, therefore all the specimens that we find in the nursery are produced from seed, and they have some years of life; for this reason, in addition to being difficult to grow, the melocactus is also expensive, which is another reason to leave these plants in the hands of experienced growers.
The Melocactus, as we said, are quite difficult to cultivate, as they need high temperatures throughout the year, low humidity and high brightness. In summer they do not like the full sun, especially if placed outdoors, so we will find a place in half 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 cultivated in a temperate greenhouse or at home, but always in a very bright place, even in full sun, which being low on the horizon will not burn the epidermis of the trunks .
Watering must be parked, to be provided only when the ground is well dry; during the winter months we will water only sporadically, with small amounts of water, while in the summer we can water about one fly a week, avoiding to supply water if it has rained, or if the soil is still wet. We always avoid to wet the cephalium, which is otherwise affected by mold and fungus.
The melocactus have a fairly broad and deep root system (compared to that of other cacti), which is why they are generally not cultivated in common cacti, which are decidedly very small; instead they settle in large bowls, so that the roots can find all the space they need. The substratum must be very porous, consisting of universal soil, mixed with pumice stone, lapillus or pozzolan, or with any material useful to simulate a rocky and very permeable soil; if cultivated in unsuitable soil, the melocactus tend to get sick easily, within a short time. The fertilizations are supplied only during 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 amounts of nitrogen, which are harmful to cacti.
Melocactus: Propagate the melocactus
These plants, unlike other cacti, do not clump and do not produce the so-called "children" at the base, even after several years of cultivation; however, the fruits always contain a certain number of small fertile seeds. Before using them, free them of the pulp and let them dry in the sun for a few days, then sprinkle them with some fungicide, so that they do not produce mold or fungus once they are placed in the seed pot.
We prepare a good seeding soil, consisting of river sand washed and peat in equal parts; let us place it in a seeding tray and water it well. It is important to wet this type of soil in advance, because it tends to take some time before rehydrating, especially if we use dry peat; furthermore, by wetting it first, we will not risk moving the seeds once they have settled down.
When the soil is well moist, place it in an under-pot, and spread the seeds, making sure to distance them well; we cover with a thin layer of vermiculite: it is an inert material, light and clear, which allows us to keep the seeds in place and to always retain a little moisture on the surface of the soil, without raising the sunlight to the seeds, which promotes germination. We place the tray in a plastic bag, which we will seal tightly, so that it works like a greenhouse, keeping the heat and humidity close to the seeds. The sowing tray should be placed in a warm and bright place, but without direct sunlight. During the following days we watch over, making sure that the soil is always moist: if it looks dry, open the bag and put a little water in the saucer.
once the plants are whined, we remove the plastic bag, taking care to keep the tray in an area that is not subject to strong winds. The young seedlings will have to be watered only when the ground is dry, and they prefer bright and warm motorcycle positions, just like the adult specimens.