Land mixtures are characterized primarily by the presence of certain components, pH (soil acidity) and looseness.
Bonsai soil usually consists of a mixture of several components.
Different types of plants require specific soil conditions. Before you start compiling an earthen mixture, you need to understand some basic techniques.
A complete potting mix intended for bonsai must meet the following requirements: retain moisture, contain minerals, oxygen to feed the roots for at least a year. The structure of the soil should provide drainage to avoid souring and decay of thin roots.
On the other hand, the soil is designed to retain moisture so that the plant is supplied with water.
A good earthen mixture is made up of granular clay with humus, humus and coarse sand - all this is mixed in proportions corresponding to each specific type of soil that characterizes the growing conditions of a tree in natural conditions.
Clay. It is highly hygroscopic and binds various other substances. Thanks to these properties, clay softens abrupt changes in the soil that are unfavorable for the plant, for example, it absorbs excess water. Nutrients, primarily phosphates, are bound by the clay and are supplied evenly.
The main function of clay is to accumulate moisture, when there is a lot of it, and release when the mixture dries. Unfortunately, ordinary clay quickly becomes dense due to its fine, almost powdery structure; at the same time, small hollow spaces, which are very important for the respiration of the root system, disappear.
Therefore, preference is given to clay granulate in the form of spheres obtained by lightly firing the starting material. This granulate retains its granular structure for one or two years and does not lose its buffering properties when the bonsai adapts to the new conditions caused by the land change.
The Japanese (and others) use several types of special clays. The best and most versatile is Akadama (named after the area). This clay is a granular substrate, consisting of 4–6 mm particles, capable of absorbing a lot of moisture and, what is most valuable, not soaking in water, not sticking together and providing a loose, lumpy and perfectly breathable mixture. In our conditions, you can use small expanded clay. According to its characteristics, it most closely matches the clay granulate.
Instead of clay, you can take the so-called meadow soil, which has a high content of loam and a porous structure of lumps.
Sand. Just like clay, it retains water, but unlike clay, which retains water inside its granules, sand retains water between grains of sand due to the capillary effect. The sand helps to maintain the moisture content of the earth mix and stabilizes the lumpy structure. Sand is needed of two types - coarse and fine.
In the earthen mixture, it plays a double role: on the one hand, it promotes drainage, and on the other, the growth of thin roots. As a result, a tree growing in a confined space absorbs water, oxygen, nutrients better. Coarse sand with a grain size of 3–4 mm is placed on the bottom of the container with a layer of 0.6–2 cm and provides drainage. Coarser sand can quickly become clogged with small particles of clay and stop letting water through, and fine sand will simply spill out through the mesh placed on the drainage holes. The standard cell size of such a mesh is 3 mm.
The lighter the soil (that is, the more permeable it is or the more sand), the less likely the roots will rot, but the more likely the plant will dry out. Perlite sand, which is great for grafting, gradually collects on the surface in the substrate, as it is very light. As for the expanded clay, which is widely sold or rolled around on construction sites, it is almost impossible to find the required size.
Lava. Used as a granulate. Lava contains trace elements and retains air in the soil, which is of great importance for respiration and gas exchange in the root system of the tree.
Peat. Serves for loosening the earthen mixture and accumulating water. Peat is an organic substrate with a low nutrient content. It is acidic in nature (pH 4.5-5), but you can reduce its acidity to pH 6 by adding lime. The peat substrate has a very diverse structure. Coarse peat is not suitable for bonsai.
Dive ground. As a rule, dive soil consists of fine-grained peat and sand, as well as a small amount of nutrients. Other composition options are possible, for example, with the addition of humus to peat and sand.
Humus, leafy earth, etc. - a supplier of nutrients. Humus is present in sufficient quantities in the upper soil layer of gardens and vegetable gardens (used only after disinfection). If it is still not enough, you can add leaf humus to the mixture. Leaf humus and rotted needles, peat, rotten bark, as well as high-quality compost with a high humus content can be used as a humus component.
Ready-made potting soil available commercially is not suitable for bonsai as such! As a rule, such soil contains many tiny particles that disturb the “bonsai” structure of the soil. In extreme cases, it can be used as an additive to the base soil.
If it is not possible to purchase a ready-made soil mixture, you can get by with three components - coarse sand (fine gravel), clay and a humus component. The mixture - humus containing humus and sand, necessary for the normal development of all plants, is in the following proportion:
The first two mixtures have a neutral acid-base reaction, the third soil mixture is characterized by high acidity (this, among other things, is good for the development of moss, which is indispensable in many compositions). You can lower the acidity of the soil by adding calcium, which is mixed with organic fertilizer. The increased acidity is reduced with peat or rotted needles.
It is important! Conifers need good drainage. Therefore, for these plants, the following proportion of soil components is proposed: for 6 parts of leaf humus, 1 part of sand. With this combination of components, the soil becomes looser and better water permeability. To increase the looseness of the soil, humus dried in the sun must be sieved, crushing small pieces.
Recently, various plant growth regulators have become more and more popular. They are mainly used to strengthen immunity, improve survival rate during transplantation, rooting cuttings and germinating seeds.
The general name "auxins" refers to indolyl-3-acetic acid (IAA) and its derivatives, growth hormones found in plants. This acid has a second name - heteroauxin. The developing tissues of the terrestrial part of the plant - young leaves, buds, and developing seeds - contain especially many auxins.
Some synthetic compounds have properties similar to IAA in their effect on plants. For example, indolyl-3-butyric acid (IMA), which is rarely found in plants, but having auxin activity, accelerates the process of root formation. This also includes 1-naphthylacetic acid (1-NAA), its potassium salt (KANU), 2-naphthylacetic acid (2-NAA), 2, 4-dichlorophenociacetic acid (2, 4-D) and others. These substances are much more resistant to destruction and binding in plant tissues, and have a long-term effect.
Use of auxins for vegetative propagation. Cuttings of not all plants root well, and in conifers, roots sometimes do not form at all. With the use of auxin, the situation can sometimes be noticeably improved. Usually, it is not the heteroauxin itself that is used, since it rapidly degrades, but its synthetic substitutes, which were mentioned above. These compounds are more stable and non-phytotoxic. Green or lignified cuttings from 2-3-year-old shoots are soaked in solutions of auxins for 8-24 hours, dipping 1/3 - 1/2 of the length. The solution is prepared at the rate of 20–75 mg of the drug per 1 liter of water. You can use a water-alcohol solution of IMC. In this case, the lower part of the cutting is immersed in the solution for only 5 seconds. The solution is prepared in the proportion: 0.5 l of water: 0.5 l of alcohol: 2.5–5 g of IMC.
For green cuttings and herbaceous plants, a lower concentration of auxins is required. Treated cuttings are planted in the ground under a film until rooting is complete. In this case, you need to monitor the humidity of the air, soil, periodically ventilate and provide protection from the sun.
The use of auxins in transplantation. A transplant for a plant is a great stress caused by damage or breakage of the suction ends of the roots. The faster the plant can restore the root system, the better its survival rate. You can help him by using auxins. Root sections are treated with a paste of clay and peat with the addition of a stimulant. You can put the roots of the plant for a day in their solutions. It should be noted that in this case mycorrhiza is lost in conifers.
After planting, the root ball is watered with a solution of hormones at the rate of 5–10 mg per liter of water. The method of dusting before planting the root system of trees with root root, a synthetic analogue of heteroauxin, has become widespread.
Used material from the book M. P. Zgurskaya "Bonsai"