How to choose orchid potting medium? Methods and tips explained in detail

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To grow orchids well, the first issue you encounter is which potting medium to choose. To choose a good potting medium, you must understand the growth characteristics of orchids. We know that the stomata on orchid leaves are sunken and respiration is incomplete, so orchids also rely on their roots to help them breathe; orchids mostly grow in places rich in humus with loose soil; orchid growing sites mostly have dry soil and high air humidity, and orchid leaves absorb moisture from the air to make up for the shortcomings of orchid roots.

Therefore, when choosing orchid potting medium, we should pay attention to the following principles:

1. Loose and breathable. In the practice of growing orchids, we know that choosing granular potting medium and abandoning powdery sticky potting medium is precisely because it creates a loose and breathable environment for orchids, making it easier for orchid roots to breathe.

2. Moisture-retaining without waterlogging. 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 immediately when 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 to pests and diseases; the growth of orchids, like other plants, cannot do without various fertilizers. A clean potting medium containing nutrients is a necessary condition for the normal growth of orchids.

According to the growth characteristics of orchids, and especially people's long-term practical experience in orchid cultivation, the potting media available for us to choose for cultivating orchids are diverse. Judging 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. Mainly including 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.

2. Organic-type media. Mainly including tree bark, rotten wood, coconut coir, wood chips, 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, breathability, and after rotting it can provide organic fertilizer for orchids, which is good for orchid root growth; the disadvantages are that it easily breeds insects and pathogens, especially during the process of decomposition and rotting it releases heat and harmful substances, which can easily burn orchid roots.

3. Hard potting media. Mainly including pond stone, zhijinshi (orchid stone), volcanic stone, pumice, perlite, broken brick pieces and ceramsite, etc. The selection of this type of potting medium is the result of people's continuous exploration and reform in the practice of orchid cultivation. 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 chosen improperly it is unfavorable for orchid root growth.

In summary, the growth characteristics of orchids provide us with convenience in choosing orchid potting medium. 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 will be determined by whether we can provide a good environment and management. The choice of orchid potting medium is an important part of the orchid growth environment. People often say: "Choose the right potting medium, and you are halfway to success in growing orchids," so we must never treat it lightly.

Facing so many orchid potting media, how exactly should we choose? The practice of our predecessors and modern orchid cultivators 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, in China's orchid circles there are three major schools in the selection of main potting media: the traditional soil-type potting medium growing method mainly in Yunnan, Guizhou and Sichuan, the hard potting medium growing method mainly in Guangdong, Fujian and Taiwan, China, and the mixed potting medium growing method mainly in Jiangsu, Zhejiang and Shanghai.

Below, the potting medium selection and matters needing attention for these three growing methods are discussed separately.

I. Traditional soil-type potting medium growing method.

As the name implies, this growing method is to choose soil-type potting media and use traditional cultivation methods 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, sieve out the powdery material, and the soil must not be too sticky. If it is too sticky, a small amount of coarse sand, wood chips, tree bark, etc. can be mixed into the soil to improve the soil properties and soil texture.

2. Pots should be breathable, open-mouthed clay pots or sweating clay pots. 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, focus on moisture; 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 material we choose contains a large amount of humus, there is no need to add base fertilizer. Usually, topdressing can be used for fertilization. At the same time, pest control and sterilization work must also be done well to prevent pests and diseases from attacking 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. Usually, orchid pots can be raised off the ground so that the pots are in an environment ventilated on all sides, and the air humidity can be relatively lower.

II. Hard potting medium growing method.

Using various hard potting media to grow orchids is a cultivation method that has become popular in China in the past dozen years or so. Compared with the traditional soil-type potting medium growing method, the greatest advantage of this growing method is that it facilitates our daily management 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 granular in varying sizes, when choosing we can generally select large particles like broad beans and small particles like soybeans. Particles that are too large are unfavorable for orchid root growth, while particles that are too small are unfavorable for drainage. When planting, if the orchid roots are thicker, more large particles can be used; if the orchid roots are thinner, more small particles 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 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 different growth stages of orchids. Usually, a combination of topdressing and base fertilizer can be used. For base fertilizer, some slow-release granular fertilizer should be chosen; for topdressing, the principle of "dilute, light, frequent" should be followed.

4. This growing method is suitable for environments with relatively high air humidity and gentle breezes. Usually, orchids should be placed in enclosed or semi-enclosed places, such as orchid farms, orchid sheds, enclosed balconies or indoors. Some snake wood chips 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 tree bark and coconut coir into this type of potting medium to improve its defect of drying easily, and at the same time it can also provide certain nutrients to orchids.

III. Mixed potting medium growing method.

Because various potting media all 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 is to mix several potting media from soil-type, hard-type and organic-type media 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 needs to be decided according to our own environment and the pots used. We can first choose a few and try growing. Generally speaking, in an open environment or a well-ventilated semi-enclosed environment, where breathable clay pots or sweating clay pots are usually used, more soil-type and organic-type potting media can be used, and less hard-type potting medium can be used; if it is an enclosed or semi-enclosed environment with relatively high air humidity, more hard-type 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, usually less or no base fertilizer can be applied, and topdressing 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 placed in a microwave oven for high-temperature treatment 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 in water, some contain saline-alkali components, and some have too much fertilizer...... We should choose carefully. Songliwang orchid potting medium produced in Hubei can be the first choice for this type of granular soil. It can be mixed with zhijinshi (orchid stone) at 1:1. This ratio is more suitable for novice friends growing orchids.

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