Practical tips on water for growing and cultivating plants

Becauseorchidsrequire a nutrient concentration of only 1/4 to 1/6 that of most fast-growing plants, it is very necessary to understand the composition of the water used for watering orchids. Although fresh, pollution-free rainwater is best, it may be hard to obtain. The examination of a water source can be divided into two parts: 1. Total salt content 2. Analysis of the content of various salts Salt content: A relatively accurate and practical method for determining the salt content in water is to measure the water's electrical conductivity (EC). Pure water is almost non-conductive, but most salts dissolved in water are conductive, and the conductivity or electrical conductivity of water is directly related to the concentration of salts in the water. The unit for measuring conductivity can be MHOM (the reciprocal of the resistance unit ohm) or expressed as siemens (S). Fororchidwater, the conductivity you measure is very small, amounting to a few millionths of a siemens, called microsiemens, represented by the symbol μS; 50 means 50μS, and 100 means 100μS. The instrument used to measure conductivity is called a conductivity meter. Instruments usually used to measure the conductivity of liquids fall into two categories: one type reads in MHOM (μS); the other type reads total dissolved salts (TDS). TDS is calibrated by a coefficient and reflects content in parts per million (PPM). But TDS obscures the fact that different salts have different conductivity (for example, urea dissolved in water is almost non-conductive). In horticulture, the conductivity unit - siemens - is mostly used, but urban water source analysis reports mostly use TDS to express analysis results. The two readings can be easily converted, roughly 1000μS is equivalent to 666TDS. The choice of conductivity meter can be based on the type of plant you are growing. Fororchids, a reading range of 1-1999μS with temperature compensation is relatively ideal, because conductivity is affected by temperature. Because orchids require a lower nutrient concentration, it is very important to use water with low salt content. The table below gives the assessment of water quality fororchidgrowing: Water conductivity Assessment ====================== Below 50μS Very good 50-100μS Good 100-200μS Acceptable Above 200μS Poor Analysis of the content of various salts: The content of various salts in water is just as important to us as the total salt content. In developed countries, some orchid or other plant associations provide their members with analysis results of the content of various salts in local water sources. The unit of the data provided is PPM, that is, the number of milligrams of a certain salt contained per liter of water. Water in many regions is relatively hard, meaning it has a relatively high salt content, and most of it contains relatively high levels of calcium and magnesium carbonates. For example, most areas of northern China with little rain. Excessive calcium and magnesium will poison orchids. It is not hard to understand that using water with low salt content enables us to better control the balanced nutrition oforchids. By the way, a reminder to our orchid-growing friends in the north: adding organic acids (oxalic acid, citric acid, etc.) to the water to neutralize the alkalinity of hard water carries a certain risk! It is true that these organic acids can indeed lower the water's conductivity at the same time, but conductivity cannot reflect the content of all salts, such as the urea mentioned earlier. Adding other salts to water that is already too salty seems inappropriate, and I hope everyone will act prudently. As I am shallow in learning and knowledge, please criticize and correct any improprieties in this article, fellow orchid growers. Beijing Du Xiao