Soilless culture of flowers is a well-known technique, while flower irrigation by pure water is not known to many people. We know that plant can not survive and grow without nutritive materials, which are not able to be absorbed or used if they are not dissolved in water. Nutrition requirements of plants vary according to different growth period. Meanwhile, the nutrition demand requirements of flowering plants and foliage plants are also different. Nutrient solution prepared using running water as solvent is influenced by other inorganic salts in water and the actual effect will be also influenced. However, if pure water is used as the solvent, interference by other ions will be greatly reduced and gardening requirements will be met to the highest extent.

Match the nutritive salts according to the nutritive material requirements of plants in different growth periods, which will not only make the plants grow better, but also can avoid waste of nutritive elements. Various salts in running water will be separated out from the surfaces of plant leaves and flowers due to water volatilization and form spots, which will affect the appearance of flowering plants and foliage plants. Soil for pot flowers accounts for a little proportion. Running water contains various salts, while the volatilized water is pure water. Therefore, soil alkalization will become worse and worse if running water is used to irrigate pot flowers, having influence on plant growth. Salt content in pure water is very low, which can help to avoid soil alkalization.

Application of pure water irrigation in gardening will improve greatly the utilization of inorganic salt and achieve the prospective best landscape effect.

 

Electric conductivity of water for gardening should be less than 100us/cm. However, most farm gardens are located in suburbs, where running water or deep well water is mostly used after simple treatment, having higher electric conductivity (even above 700us/cm), not good for the growth of pot plants. Therefore, desalinization shall be performed for water for gardening and the ratio of desalinization must be retained above 85%.

There are mainly several methods for water desalinization, such as electrodialysis, sodium filtration, ion exchange and reverse osmosis. Ratio of desalinization by electrodialysis is only about 60%, difficult to ensure the requirements of water for gardening. Ratio of desalinization by sodium filtration is around 80%, but sodium filtration removes the salts contained in water selectively, having higher removal ratio of calcium and magnesium, as high as 95%. However, the removal ratio of salts with little ionic radius such as sodium is quite low. Therefore, sodium filtration is not an ideal desalinization method on occasions with higher chloride content, such as areas having back flow of seawater and brackish water.

Ideal ratio of desalinization can be achieved by both ion exchange and reverse osmosis. The ion exchange resin shall be regenerated with acid and alkalis after saturation. So acid and alkalis waste fluid will be discharged. Besides, there are also storages of hydrochloric acid and sodium hydroxide on the spot. Improper management will bring secondary pollution, endangering planting stocks possibly.