What are the methods for selecting orchid potting media?

To groworchidswell, the first issue you will encounter is what kind of potting medium to choose. To choose a good potting medium, you must understand theorchid'sgrowth characteristics. We know that the stomata on orchid leaves are sunken, so respiration is incomplete, and the plant must also rely on its roots to help it breathe;orchidsmostly grow in places rich in humus with loose soil; orchid growing sites usually have dry soil and high air humidity, and orchid leaves absorb moisture from the air to make up for the shortcomings of the orchid roots. Therefore, when choosingorchid-growingpotting media, we should pay attention to the following principles: 1. Loose and breathable. Inorchid-growingpractice, we know that the reason for choosing granular potting media and discarding powdery ones is to create a loose, breathable environment for the orchids, making it easier for the orchid roots to breathe. 2. Moisture-retaining without becoming waterlogged. An orchid is a plant and needs moisture; but orchid roots are fleshy roots and cannot tolerate waterlogging. A good potting medium allows water to flow through as soon as it is watered, never accumulates water, and can still remain moist for a relatively long time. 3. Clean and containing nutrients. Wild orchids have strong resistance, but after transplanting their resistance weakens, and they are more susceptible topests and diseases; theorchid'sgrowth, like that of other plants, cannot be separated from various fertilizers. A clean potting medium containing nutrients is a necessary condition for the normal growth of orchids. According to theorchid'sgrowth characteristics, and especially people's long-term practical experience in orchid cultivation, thecultivationoforchidsallows us to choose from a wide variety of potting media. From the potting media widely used by people and sold on the market, they can be roughly divided into the following three major categories: 1. Soil-type media. These mainly include mountain soil, pond mud, bamboo root soil, peat soil, and various humus soils, etc. This type of potting medium is the main material of traditional growing methods. Its advantages are moisture retention, nutrient content, easy availability, and low price; its disadvantages are that it easily compacts and accumulates water, is not easy to dry after thorough watering, and contains pathogens and easily breeds insects. (The Sichuan Xiantu currently sold on the market and some artificially made granular soil are no longer soil-type media in the traditional sense; this will be discussed later.) 2. Organic-type media. These mainly include bark, rotten wood, coconut coir, wood shavings, sugarcane bagasse, peanut shells, snake wood, palm fiber, and moss-type plants, etc. The main advantages of this type of potting medium are moisture retention and breathability, and after rotting it can provide organic fertilizer for orchids, which is beneficial for orchid root growth; the disadvantages are that it easily breeds insects and pathogens, and especially during the process of decomposition and rotting it releases heat and harmful substances, which can easily burn orchid roots. 3. Hard potting media. These mainly include pond foundation stone, zhijinshi, volcanic stone, pumice, perlite, crushed brick pieces, and ceramsite, etc. The selection of this type of potting medium is the result of people's continuous exploration and reform in orchid-growing practice. Its advantages are that it is granular and not easily broken down, clean and does not breed insects, has good breathability and does not compact, and does not accumulate water; the disadvantages are that it dries easily, contains no nutrients, and if the particle size is not chosen properly it is unfavorable for orchid root growth. In summary, the growth characteristics of orchids provide us with convenience in choosingorchid-growingpotting media. However, orchids are living things, and they will live for a long time in the small environment we choose for them; whether they grow well or poorly will be determined by whether we can provide a good environment and management. The choice of orchid-growing potting medium is an important part of the orchid's growing environment. People often say: "Choose the right potting medium, and you are halfway to successful orchid growing," so we must never take it lightly. Faced with so many orchid potting media, how exactly should we choose? The practice of our predecessors and modern orchid growers has proven that as long as it conforms to the growth characteristics of orchids, any kind of potting medium can grow orchids well; the key is that different potting media are suitable for different environments, different pots, and different management. At present, there are three major schools in China's orchid community regarding the selection of main potting media: the traditional soil-type growing method centered on Yunnan, Guizhou, Sichuan, and other places; the hard potting medium growing method centered on Guangdong, Fujian, Taiwan, China, and other places; and the mixed-type potting medium growing method centered on Jiangsu, Zhejiang, Shanghai, and other places. Below, the potting medium selection and matters needing attention for these three growing methods are discussed separately. 1. Traditional soil-type potting medium growing method. As the name implies, this growing method uses soil-type potting media and adopts traditionalcultivationmethods to grow orchids. We have already analyzed the advantages and disadvantages of this type of potting medium above, so when choosing this type of potting medium to grow orchids, we should pay attention to the following matters: 1. Use granular material as much as possible, sift out the powdery part, and the soil must not be too sticky; if it is too sticky, a small amount of coarse sand, wood shavings, bark, etc. can be mixed into the soil to improve its properties and texture. ? 2. For pots, choose unglazed clay pots or sweating clay pots with good breathability and an open mouth; a drainage layer must be placed at the bottom of the pot to prevent soil from clogging the drainage holes and causing water accumulation. 3. In daily management, "dry growing" should be the main approach, that is, when watering we must grasp the principle of "do not water until dry, mainly keep moist; better a little dry than too wet." However, we must also pay attention to preventing the phenomenon of drying from the bottom of the pot upward, that is, watering must be thorough. 4. Because the soil medium we choose contains a large amount of humus, there is no need to add base fertilizer; ordinarily we can choose to fertilize by top dressing, and at the same time we must do a good job of insecticide and sterilization to preventpests and diseasesfrom attacking the orchids. 5. The place where orchids are placed should be a well-ventilated site, such as an open or semi-enclosed place like a courtyard or balcony; ordinarily the orchid pots can be raised off the ground so that the pots are in an environment with ventilation on all sides, and the air humidity can be relatively lower. 2. Hard potting medium growing method. Using various hard potting media to grow orchids is acultivationmethod that has become popular in China in the past ten-plus years. Compared with the traditional soil-type potting medium growing method, the greatest advantage of this growing method is that it makes our daily management more convenient and speeds up the growth rate of orchids. But it also has very obvious defects. Therefore, when we choose this type of potting medium to grow orchids, we must not ignore the following matters: 1. Because this type of potting medium itself is usually in the form of granules of varying sizes, when selecting it we can generally choose large grains like broad beans and small grains like soybeans. If the granules are too large, it is unfavorable for orchid root growth; if too small, it is unfavorable for drainage. When planting, if the orchid roots are thicker, more large grains can be used; if the orchid roots are thinner, more small grains can be used. 2. In daily management, the "wet growing" method can be used to cultivate orchids, that is, always keep the potting medium moist. However, we should still follow the principle of using different watering methods according to differences in pot material and differences in the strength of the orchid seedlings, and must never overwater. 3. This type of potting medium itself contains no nutrients, and artificial fertilization is needed to ensure the normal growth of orchids. We should pay attention to applying different fertilizers according to the different growth stages of orchids; ordinarily we can use a combination of top dressing and base fertilizer, and for base fertilizer we should choose some slow-release granular fertilizers; top dressing should follow the principle of "dilute, light, and frequent." 4. This growing method is suitable for environments with relatively high air humidity and gentle breezes; ordinarily orchids should be placed in enclosed or semi-enclosed places, such as orchid nurseries, orchid sheds, enclosed balconies, or indoors. Some snake wood shavings or sphagnum moss, etc. can be placed on the pot surface to keep the surface granules moist. 5. When using it, we can mix a small amount of organic potting media such as bark and coconut coir into this type of potting medium to improve its shortcoming of drying easily, and at the same time it can also provide certain nutrients to the orchids. 3. Mixed potting medium growing method. Because all kinds of potting media have their own defects, using a single potting medium to grow orchids not only requires certain environments and conditions, but also brings inconvenience to our management. The emergence and use of the mixed potting medium growing method can be said to be a great progress in the history of orchid cultivation. This growing method mixes several kinds of potting media from soil-type, hard, and organic types to prepare a new potting medium for growing orchids. Its greatest advantage is that during the preparation process we can increase or decrease the various potting media according to our own environment, pots, and management methods to meet the needs of orchid growth. Likewise, when using this type of potting medium we need to pay attention to the following matters: 1. Which several potting media we choose and in what proportions during preparation must be decided according to our own environment and the pots used; we can first choose a few to test. Generally speaking, in an open environment or a well-ventilated semi-enclosed environment, where unglazed clay pots or sweating clay pots with good breathability are ordinarily used, more soil-type and organic-type potting media can be used, and less hard potting medium can be used; if it is an enclosed or semi-enclosed environment with relatively high air humidity, more hard potting medium and organic-type potting media can be used, and less soil-type potting medium can be used. 2. Because this type of potting medium contains certain nutrients, ordinarily less or no base fertilizer can be applied, and top dressing should be the main method, following the principle of "light fertilizer applied frequently." 3. The soil-type and organic-type potting media we choose when preparing this type of potting medium may contain pathogens and pests, so before preparation we must use chemicals or high temperature to sterilize and kill insects. At the same time, organic-type potting media easily produce heat and harmful substances during the process of rotting and decomposition, so before use they can be soaked in water and then treated at high temperature in a microwave oven to solve this problem. 4. When preparing this type of potting medium, we often use some artificially made granular soil. This type of granular soil indeed has many advantages, but it also has many problems. For example, some use adhesives harmful to orchids, some cannot withstand soaking, some contain saline-alkali components, and some have too much fertilizer...... We should choose cautiously. After use, the "Hewang" brand Xiantu produced in Sichuan can serve as the first choice for this type of granular soil, except that before use it needs to be soaked for more than 24 hours.