Most of the succulents belong to the cactaceae family, or more commonly cacti, which groups about 3000 species and 120 genera. Cacti are xerophytic plants that live in arid environments thanks to the accumulation of water inside the succulent tissues. These plants are mainly used as ornamentals and for their ease of cultivation.
Cacti are succulents that can take different forms: there are those with a globose or flattened appearance, those colonized and can both live in large groups and as single plants. These plants are all perennial and mostly native to the countries of the New World, although there are species typical of Africa, Madagascar and Sri Lanka; however, most of them can be grown without problems even in our latitudes.
A common feature of the Cacti, often called simply Cactus, from the Greek "Kaktos", or thorny plant, is to have a root system deep enough to go in search of water in the depths of the subsoil. They are almost all devoid of leaves, at least as we are used to seeing them and photosynthesis takes place thanks to the stem and strictly at night so as not to lose water.
All the plants of this family have solitary, sessile flowers, generally with showy colors, which sprout in spring and summer and which, often, remain in bloom for a single night. The fruits are generally fleshy and of variable size, can be covered with thorns and always contain many seeds impregnated with a sugary substance.
Generally these plants are grown for ornamental purposes; many fruits of these plants are edible, the prickly pear among all; in the Andean countries the Cacti are also used for the production of light wood for the manufacture of small artifacts, while in Argentina some columnar species are also used for the construction of fences.
Cultivation
In regions where winters are too humid, it is advisable to grow cacti in greenhouses or in glazed caissons, since they can also withstand the night in a very cold environment, as long as it is dry. On the contrary, they could not survive a cold and humid atmosphere.
The compounds for the pots, preferably in synthetic material and not in terracotta, used to grow cacti must be particularly porous, so that the air can circulate and there is no stagnation of moisture.
It will therefore be necessary to add very fine sand, grit or brick shards to ensure good drainage. Cacti of the epiphytic group also require an addition of humus to the compound already contained in the pot. Leaf topsoil, peat will do well, and in any case, the soil must be well drained.
Succulents need, in the winter period, heat, but care must be taken that this is a dry heat and that a stagnant atmosphere is not formed, which could be a source of moisture.
