Selecting and Applying Succulent Growing Media
Core introduction to the text: content about succulent plants, selection and application of succulent growing media. The editor will provide a detailed explanation.
Growing media refers to the medium for the growth of potted flower roots, mainly to fix the plants and provide nutrients. This medium is not only soil, but also various soilless cultivation media of organic and inorganic types, such as bark, peat, vermiculite, ceramsite, and lanite, as well as alternative materials like coal cinder, rock wool, polyester foam particles, and rotten cotton. This also includes hydroponics and air cultivation.
In theory, any material that can maintain its physical structure without easy change during the process of water and root growth, without producing drastic chemical changes, and can absorb and slowly release water and nutrients with moderate particle size can be used as cultivation media.
However, this is just a theory. In most cases, plants can only grow in media suitable for themselves. The so-called "suitable" includes many factors, the most important of which is the pH value, soil salinity content (EC), medium composition, organic matter content, decomposition degree, particle size, etc. In addition, a single medium is not suitable for cultivating plants because it cannot provide comprehensive nutrients, or the content of a certain component is too concentrated.
Here, we need to promote a concept - the root-friendly nature of the medium. The root-friendly nature of the medium should actually be called the selectivity of the roots for the medium. Simply put, the stronger the root-friendly nature of an object, the more the root hairs of the plant like to climb on it. This characteristic is determined by the chemical properties, physical form, and particle size of the planting material. Generally, media with smaller particles, lower hardness, looser texture, and slightly acidic nature have stronger root-friendly nature. Root-friendly nature is very important, indicating that the various properties of the medium are very suitable for plants. The root hairs can grow and absorb water and nutrients on it for a long time. Of course, it doesn't mean that there are no root hairs attached to other planting materials with poor root-friendly nature because the selection of planting materials by plant roots is not pre-ordained, but corrected afterwards. Therefore, root hairs will also attempt to grow on planting materials with poor root-friendly nature, but their lifespan will be short, which will invisibly increase the consumption of plants and waste energy. Over time, the growth gap of plants will be significant. When we repot plants, we often see that some plants have clean roots, with both thick and thin roots being smooth. While other plants have dirty roots, covered with planting materials from top to bottom. If you observe carefully, you will find that the latter's root hairs are more developed, and the upper part is often healthier. The planting materials used for these two pots of plants are often not the same, which illustrates the existence of the root-friendly nature of the medium.
Theory is not elaborated much here. Let's talk about practical matters.
1. Introduction to various cultivation media:
(1) Akadama soil
For home succulent cultivation, the best option is to imitate the soil of the original habitat. The company where Lao Jiang used to work had a project department in the southern part of Africa. Therefore, Lao Jiang once asked local colleagues to help study the wild soil. Generally speaking, the local soil in Africa is sandy, with sand and gravel accounting for about 80% of the content. There is a thin layer of humus covering the soil surface in some tree-shaded and grassy areas. The soil moisture content is extremely low, and no moisture is found even when digging 1 meter deep in vast areas. However, in areas covered by shrubs, slight moisture can be seen below 30 centimeters. From this analysis, the soil composition of the original habitat is equivalent to coarse sand + decomposed leaves + gravel. Such soil is not difficult for most succulent plant enthusiasts to obtain, and enthusiasts in Europe and the United States are indeed using such media to cultivate succulent plants with good results. However, for home cultivation, such soil is too heavy, and it is not very suitable for enthusiasts who cultivate a large number of plants on balconies or flower stands. Moreover, it is relatively rough and does not meet the preferences of most students (most students who like succulent plants have a phobia of dirt, don't they).
Therefore, the petite bourgeoisie represented by the Japanese people have developed cultivation soil mainly composed of Akadama and Rumiko volcanic ash, which not only meets the needs of most enthusiasts in China but also contributes to the economy of the island country. The materials represented by these two types of soil are quite conventional, and their components theoretically meet the maximum requirements of plants for media. The history of using Akadama soil in Japan can be traced back to 20 years ago when "Cherry Blossom Mako" was popular. In one episode, Mako's grandfather was sifting Akadama soil, which can be considered an early form of product placement.
In addition to succulent plants, the Japanese also extensively use Akadama in the cultivation of other plants. They have developed products suitable for different purposes based on different origins. Lao Jiang is not helping to advertise Akadama soil. Japan is a gardening powerhouse, but its land area is small, and resources are scarce. Making full use of its volcanic conditions is a necessary measure. Of course, there are ways for the poor to cultivate flowers. They dig volcanic ash from the foot of Mount Fuji and collect rotten leaves from crooked trees in their backyard, mix them together, and use them for planting. Surprisingly, the results are quite good. Therefore, this limited resource has been continuously developed, researched, and systematized, forming a very sound industrial chain. Large-scale and corporate things naturally have enough competitiveness, so the Xian soil from Sichuan and peat from Northeast China have been surpassed... Of course, I am not superstitious about Japanese goods, but I believe in the system. Things under the system are generally more stable than those produced by small workshops.
The biggest advantage of Akadama soil is its low fertility, slight acidity, breathability, and water retention. These four aspects almost meet the physiological needs of most plants. For the physiological characteristics of succulent plants, it is almost a perfect match. Generally, beginner players can cultivate succulent plants well without much guidance when using Akadama soil, so it can be called a "foolproof soil." Its characteristics greatly lower the threshold for succulent plant cultivation. Additionally, the price is moderate, so Akadama soil can also be said to be an important factor promoting the rapid development of succulent plants in China.
It is important to note that not all Akadama soil is suitable for succulent plant cultivation. Different origins have different functions. For succulent plants, the "Longquan" brand sold in China is the most suitable. Many students like to use "Nibenxian," which emphasizes solidity and resistance to pulverization. Its texture is high-temperature sintered heavy clay with poor breathability. Once it becomes pulverized, the soil structure in the pot will be greatly damaged. Moreover, due to its hardness, its root-friendly nature is also poor. It is勉强 suitable for growing orchids, flowering plants, and pine plants, but not very suitable for succulent plants. The texture of "Longquan" is sandy soil, although its granulosity is poor and it is prone to cracking, its texture determines that even if it is completely crushed, it is sandy loam. Its basic functions will not be completely lost. Moreover, "Longquan" is not like "Nibenxian," which is sintered soil. Therefore, its organic matter content is relatively higher, and the soil composition is close to that of the original habitat soil. (Don't ask why Lao Jiang knows so much. At that time, I didn't mind being ridiculed by asking many experts what Akadama they used. So, the experts I asked can testify that this conclusion is not fabricated by Lao Jiang).
Of course, other materials are not useless either. On the contrary, many materials, although not comprehensive in function, have characteristics that greatly surpass those of the conventional Akadama soil. For example:
(2) Peat
Peat is formed by the accumulation of decomposed plant residues of shrubs and mosses over thousands of years. Lowland peat, derived from swamp plants, has high water content, severe decomposition, and high humus content, but with high EC value and low pH value. Northeast black peat is a representative of this type. Highland peat, derived from mosses and lichens in plateau and local plain areas, has low decomposition due to long-term dry environment and frequent exposure to sunlight and rain, resulting in low humus content but also low EC value and slightly acidic pH value, represented by imported FFD peat. For plants, low decomposition, high humus content, low EC value, and slightly acidic pH value are the best choices. Therefore, these two types of peat have their own advantages in terms of characteristics. However, in general, highland peat is more beneficial for cultivating succulent plants.
We usually use peat as a medium to provide organic matter in the soil mixture. Adding it to the soil mixture can also loosen the soil texture, strengthen the soil's buffering capacity for fertilizer and water, and create a microenvironment suitable for the growth of plant root hairs, which has a significant effect on the rooting and rejuvenation of seedlings and weak seedlings.
(3) Lanite
Lanite is generally considered to be a product of volcanic ash, such as pumice, foot scrubbing stones, and other high-temperature foamed ores. However, there are also artificial alternatives, such as Tangji Lanite and Nishiko stones. Since their properties are similar, they are not described separately here. This article collectively refers to them as Lanite.
Lanite is harder than soil and has weaker water retention capacity after absorbing water, so it can be considered a water-repellent material. Its internal pores can temporarily store water, but since they cannot reach the level of capillary action, the water evaporates quickly. However, its pores can reduce soil density and achieve the effect of loosening the soil. The pH value of natural volcanic ash Lanite should be acidic, but artificial alternatives tested by Lao Jiang are slightly alkaline, so they should be treated differently when used.
Since Lanite has a lower water saturation level compared to soil, adding Lanite to the soil mixture can reduce the overall water saturation level of the potting soil, relatively increasing the oxygen content in the soil. This is not the "breathability" we usually think of, as stones cannot breathe. The so-called breathability is just an indirect effect.
Lanite is fertilizer-free, and the EC value varies greatly depending on the origin or source. It is generally believed that artificial alternatives have a slightly higher EC value, so natural materials should be chosen first in practice.
(4) Bark
There are two common types of bark that can be used as gardening materials: pine bark (the lumps on the outside of pine bark) and decomposed bark from deciduous trees. Pine bark is expensive and has very low decomposition, so it is generally used as gardening cover material and is not suitable for use as cultivation medium. Decomposed bark from deciduous trees is mostly produced from natural decomposed accumulation layers in hilly areas of the central plains. The suitable decomposition degree is 3-5 years. Compared to peat, its structure is more stable and less prone to compression deformation, leading to soil compaction. Additionally, bark has better ability to slowly release organic matter, making it a very good material.
The only drawback of bark is that it is prone to contain impurities. Since it is mostly harvested naturally, it inevitably contains insect eggs, weed seeds, and other organic matter that has not been completely decomposed. This can easily lead to excessive biomass in the pot after planting, commonly known as the breeding of pests and fungi. Therefore, bark needs to be screened, sun-dried, or heat-treated before use, which is a major limitation in home environments.
(5) Vermiculite
Vermiculite is the high-temperature expanded product of mica rock. Compared to the original ore, it is like the difference between popcorn and rice. Vermiculite has a very low density and large internal voids, commonly used as insulation materials in industry. In horticulture, it is used to loosen the soil, facilitate rapid water penetration, water