Vital element for the plant, which draws their raw materials from it for their subsistence, the soil takes on an increased importance for any container culture. It is necessary to achieve that, in a restricted volume, the roots can quickly hang on, feed, drink without drowning and also breathe.
The ideal land, various essential components
Gardeners use the term “earth” to refer to the cultivable part of the soil, where various mineral components mix: sand, clay, limestone and organic elements designated under the generic term ” humus “. The earth is a complex and unstable structure, subject to permanent aggression from bad weather, climates and micro-organisms.
In a pot, the external environment does not intervene on the behavior and the quality of the soil, it is necessary to define its composition. The compactness must be sufficient to support the whole plant, with well hooked roots. The water retention capacity is essential for fertility, the roots drawing their nourishment in the form of diluted mineral salts.
However, the earth must not turn into a quagmire, aeration being necessary for the oxygenation of the roots.
Our advice: Professionals produce plants in pots under controlled conditions of humidity, fertilization and watering. They use substrates based on blond peat, a flexible, porous, light material, but difficult to master for an amateur. So repot any plant immediately after purchase.
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In its ideal theoretical composition, good garden soil consists of 60% sand, 25% clay, 10% limestone and 5% humus. When it comes close to this formula, it is called “freehold”. Be careful, the term “topsoil”, which is used wrongly and through, often corresponds to salvage or backfill land, of very poor agronomic quality.
Garden soil is not used pure in pots, because it has a structure that is too heterogeneous, too compact and, above all, tends to settle down as watering progresses. Garden soil is used in mixtures for large plants (palm trees, citrus fruits, ficus, philos, yuccas, dracaenas), in a proportion of 20 to 50%.
One should rather say “the potting soil”, because, in its first sense, this term indicates the product of the decomposition of a simple organic matter.
So there are potting soils of leaves, manure, bark, peat, etc. If we refer to the definition of Petit Larousse, the soil is: ” soil mixed with decomposed animal or vegetable matter “, That is to say what gardeners today designate under the term” compost “considered as an amendment and not a growing medium. Compost is defined as a ” fermented mixture of organic and mineral residues, lime and earth that turns into potting soil “.
The only nuance is therefore found in the degree of decomposition of organic matter … In practice, the soil is a mixture of different mineral and organic components, in which plants grow. It is referred to by the generic term of “growing medium”, which means that the soil can be used pure for the cultivation of potted plants and above all plays a role of anchoring element for the roots. This is what differentiates it from amendments (manure compost or lime for example), which can be used in the composition of potting soil, but are too rich or too poorly balanced to be used pure as growing media.
The term “substrate” denotes a mixture of different types of soil, minerals and potting soil, specifically adapted to the cultivation of one type of plant or of a group of plants.
The “ready-to-use” products offered in bags are more and more specialized, in order to make your job easier, while guaranteeing you success.
- The green plant soil is the basic blend, often offered at promotional prices. Its quality is not always excellent. Heavy formulas that form lumps will be lightened with sand. Products that are too soft and peaty will be reinforced with garden soil.
- The cacti soil is intended for: succulents, cacti, sansevière, beaucarnéa, yucca. It is often a mixture of sand and various peats, also containing pozzolana, which acts as an aerator for the chippings.
- Bonsai soil must contain clay soil to provide good structure. It is lightened by peat, composted bark and pozzolana. Add 10% sand to it.
- Citrus soil also suitable for olive trees, palm trees, bougainvillea and Mediterranean woody plants (Solanum, Hibiscus). Rich and compact, it combines clay soil, sand, peat, bark.
- Orchid soil must not contain soil. A good product is made up of fine elements: bark, synthetic moss, polystyrene beads, sphagnum, fern roots.
- The potting soil with water reserve incorporates clay balls in a flexible and porous mixture, where the peat must not exceed 50%.
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