Soil
Along with water, light and warmth, the other vital factor to cacti is the soil. When die cactus absorbs the water in the ground it also takes in the nutritive salts dissolved in it. Cacti require no great quantities of these salts.
The dry substance of the cactus body is a small proportion of its weight, and most of that consists of organic materials (principally cellulose), which are formed by photosynthesis. The absorbed nutritive salts correspond to ash.
Even in a globular cactus weighing about 100 grams this only amounts to about 0.5 gram. It follows that heavy doses of fertilizer containing mineral salts are not growing species As cacti have relatively low osmotic values, and therefore do not develop great suction forces, they are only capable of absorbing very weak solutions of fertilizer.
If a higher concentration is given their roots even tend to lose water. Terrain whose surface is continually enriched with easily soluble sails, as occurs quite frequently in hot, dry areas, is not usually colonized by cacti.
On die other hand, land with a hard superficial crust of gypsum crystals, which are not highly soluble, is often found colonized by Most cacti prefer a slightly acid soil and do not like any substantial proportion of lime which pushes the pH value of the soil into the alkaline loose, welUdrained soil, as their roots require access to the oxygen of the air, which is only available in sufficient quantities if the soil is not densely packed.
Usually it is not the specific type of soil - clay, loam, sand, leaf mould, etc. - which is crucial to success with cacti, but rather particular characteristics of that soil, such as its pH value and its porosity.
This is evident from the fact that in culture these soil constituents can be replaced by quite different materials whose only similarity is in die physical or chemical characteristics mentioned. Even artificial soils such as styromull, Pcrlite etc., can possess these qualities. Most cacti have even been successfully cultivated by the hydroculture technique.
Nevertheless the fact remains that many species of cactus require specific types of soil. Where this is the case the section of the book dealing with that species or genus mentions the fact.
Along with water, light and warmth, the other vital factor to cacti is the soil. When die cactus absorbs the water in the ground it also takes in the nutritive salts dissolved in it. Cacti require no great quantities of these salts.
The dry substance of the cactus body is a small proportion of its weight, and most of that consists of organic materials (principally cellulose), which are formed by photosynthesis. The absorbed nutritive salts correspond to ash.
Even in a globular cactus weighing about 100 grams this only amounts to about 0.5 gram. It follows that heavy doses of fertilizer containing mineral salts are not growing species As cacti have relatively low osmotic values, and therefore do not develop great suction forces, they are only capable of absorbing very weak solutions of fertilizer.
If a higher concentration is given their roots even tend to lose water. Terrain whose surface is continually enriched with easily soluble sails, as occurs quite frequently in hot, dry areas, is not usually colonized by cacti.
On die other hand, land with a hard superficial crust of gypsum crystals, which are not highly soluble, is often found colonized by Most cacti prefer a slightly acid soil and do not like any substantial proportion of lime which pushes the pH value of the soil into the alkaline loose, welUdrained soil, as their roots require access to the oxygen of the air, which is only available in sufficient quantities if the soil is not densely packed.
Usually it is not the specific type of soil - clay, loam, sand, leaf mould, etc. - which is crucial to success with cacti, but rather particular characteristics of that soil, such as its pH value and its porosity.
This is evident from the fact that in culture these soil constituents can be replaced by quite different materials whose only similarity is in die physical or chemical characteristics mentioned. Even artificial soils such as styromull, Pcrlite etc., can possess these qualities. Most cacti have even been successfully cultivated by the hydroculture technique.
Nevertheless the fact remains that many species of cactus require specific types of soil. Where this is the case the section of the book dealing with that species or genus mentions the fact.
