Tips for Using Lime in Orchid Cultivation and Management

Yesterday I talked about using the alkaline leachate from carbonized "plant ash" to neutralize the acidity in the growing medium, thereby achieving a targeted preventive effect. Today I will talk about "lime" inorchidcultivationmanagement techniques, hoping to give orchid enthusiasts a dual option during the hot and humid plum rain season. We know that "lime" has made indispensable contributions to the prevention and control of crop diseases, such as: "lime" and "sulfur" being neutralized and boiled into the well-known "lime-sulfur mixture" (lime-sulfur mixture is widely used in forest and fruit treecultivation, and every agricultural technology station has prepared solutions for sale), and mixed with "copper sulfate" to make the famous "Bordeaux mixture" (first the two solids need to be dissolved in water into liquids before being mixed in a specific procedure). The above two preparations have professional instructions for their production and use, so I will skip them here and not introduce them further. But one point to note as an aside is that "Bordeaux mixture" has already been applied inorchidcultivationwith practical examples, and according to feedback the results are remarkable. What is referred to here is for large-scale cultivation, while small-scale cultivation does not need this, because "Bordeaux mixture" must be used immediately after mixing, and moreover the requirements during the preparation process are very strict. Therefore, for small-scaleorchidenthusiasts it is not applicable, so there is no need to discuss it in detail. In addition, "lime" mixed into a thin paste also has great significance for the protection of trees in winter. Powdered "lime" also has a noteworthy contribution in large-scale sterilization (what is referred to here is environmental sterilization), such as: it was widely used in the environmental sterilization of the H5 avian influenza virus this spring. As is well known, "lime" belongs to strongly alkaline media, and has the advantages of being able to quickly suppress and kill fungi that prefer to survive in acidic environments, with few side effects and little residue, which is also the main factor for its widespread use in crop prevention. What people do not realize is that "lime" in the sterilization process must not be used carelessly either. Below I will discuss the scientific application of "lime" in orchid cultivation and management. I. About the Selection of "Lime" First we must select high-quality "lime". Selecting high-quality "lime" should start from the following two aspects: 1. Visual inspection: Through visual inspection, we see that large pieces with a pure white or slightly yellowish appearance and without weathering are high-quality "lime lumps". 2. Feel: This point is very important in selecting high-quality "lime lumps". The lighter the "lime lump" feels in the hand, the better (compared with other "lime lumps" of the same size). The lighter ones have been fully burned and have high purity. On the contrary, the heavier ones are due to incomplete burning during the combustion process, resulting in higher impurity content, and are not desirable. II. About the Production and Use of "Lime" Clear Liquid 1. First, the high-quality "lime lumps" should be soaked or drenched with water to turn them into powder, then take pure "lime powder" and dilute it with water at a ratio of 1:10 to make an aqueous solution (the "lime powder" that has just been drenched and dissolved with water must not be taken hastily; for safety's sake, wait until it has naturally cooled before taking it). After soaking for about 12 hours and fully decomposing, the clear liquid can be carefully taken out. Note that when taking the clear liquid, a layer of "crystalline substance" like thin ice will solidify on the surface of the clear liquid. This "crystalline substance" like thin ice is a high-purity alkaline substance crystallized, and should be considered undesirable. Furthermore, this "crystalline substance" is not easy to dissolve in the subsequent water dilution, and once it enters the leaf core of tender tissue it will cause phytotoxicity, and it easily clogs spray nozzles, so discard it. 2. Take "lime" clear stock solution and dilute it with water at a ratio of 1:2000 to make an aqueous preparation. During the hot and humid plum rain season, adopt a "ground and air combined operation": first irrigate to let the medium in the entire pot be penetrated, then spray the entire orchid room and orchid site so that the preparation fully covers them, in order to suppress or kill fungi that prefer to survive in acidic environments over a large area. In this way, using it twice at intervals during the hot and humid plum rain season will effectively control the occurrence of "stem rot,soft rotdisease, and southern blight". Note: Large orchid farms generally spread powdered "lime" on the ground to seal off and kill pathogenic fungi on the ground surface, but this operation is highly polluting, with "flying dust" during operation, and it easily pollutes orchid leaves and causes damage to them, so it is not desirable. Note: 1. The "lime" clear liquid aqueous solvent is purely alkaline, so it cannot be mixed with any acidic pesticides or chemical fertilizers or organic fertilizers. Note: 2. The "lime" clear liquid aqueous solvent has high alkali purity; when diluting with water, be sure to ensure it is above 2000 times. Slightly more water is fine; please do not arbitrarily reduce the amount of water used for dilution. Note: 3. This preparation is only effective against fungi that prefer to survive in acidic environments; the principle is "prevention first". The above is for reference only. Interested orchid enthusiasts may wish to practice it again (personal experience is also a delightful thing). Solemn statement: This "lime" leachate aqueous preparation is not a panacea, and it should not be relied upon for long-term use. Please alternate medications in cultivation and management to reduce the drug resistance of fungi and the possibility of the growing medium becoming alkaline. (Wan Yunkun)