Unfavorable irrigation water or improper fertilization often turn the normally acidic plant material into alkaline. This is expressed in moss- and blue algae formation; the plants get yellow leaves despite the best care. One can counteract this condition, if in the growing season weekly or fortnightly with a phosphate solution 1:1000 is poured. Has the level of alkalinity already risen too high?, transplanting is absolutely necessary. The root ball should be washed out thoroughly beforehand with lukewarm water, use it to flush out as many harmful substances as possible.
Pond-, Bach- or river water must be checked for pH and hardness prior to use. The basic requirement is security, that it does not contain chemical contaminants from industrial plants. Based on what was said at the beginning, there is a certain probability that the surface water will have favorable degrees of hardness, where the subsoil consists of water-impermeable or water-insoluble rocks. The source is also in such areas- and well water soft, u.U. almost like rainwater.
If only water with too high a degree of hardness is available, it must be softened chemically. Detailed instructions cannot be given here, since the commercially available devices as well as the properties of the ion exchangers are different. However, the principle is the same. Fine granulated synthetic resins, the so-called ion exchangers, bind with the passage of hard water or its mineral salts. exchange them, so that an end product is created, whose purity comes close to that of distilled water. After a certain amount of water to be desalinated has passed through, the ion exchangers have to be regenerated, what is done by appropriate chemicals. The workload is relatively low, the costs as well. Exclusive and permanent use of such deionized water is not advisable, because there is a lack of nutrients. They are to be added to the water in the form of inorganic fertilizer according to the guidelines given in the "Nutrition" section before it is used. The type of plants is decisive, their age and state of development, the location and the season. The use of ionized water offers an advantage in this respect, because due to its purity, the type and amount of nutrients added can be precisely tailored to the needs of the plants.
The temperature of the pouring- or. Splashing water is of some importance. An old gardening rule says, that the water should be about the same temperature as the air. One should roughly act on it. Small differences do not matter. Big temperature differences, as they can arise when spraying heavily sunlit plants with cold water, are detrimental to them. Any damage that occurs may be. not at all directly visible or only after a long time.
1 Laelia pumila var. excellent; 2 Dendrobium devonianum; 3 Cattleya citrina; 4 C. bowringiana