Water Quality and Plant Growth in Hydroponics
If there are issues with water quality, a thorough water analysis may frequently identify the source of some difficulties, such as salinity or excessive levels of trace elements, however numerous additional factors may also be at play. It can be difficult to determine if a water quality issue is responsible for plant growth problems and symptoms that might be occurring Many diseases and errors with nutrient management or incorrect environmental conditions produce symptoms similar to common water quality problems and detecting issues such as chemical or microbial contamination is more complex.
Water testing and laboratory analysis for plant pathogens and other microbial contamination can be carried out and are essential for those producing salad greens, lettuce, micro greens and sprouts to ensure water is of acceptable quality that meets food safety standards. For other water quality issues, the simplest method to determine if water quality is the cause of growth problems is to run a seedling trial and grow sensitive seedlings such as lettuce using RO or distilled water as a control or comparison.
Keeping all other growth factors such as nutrients, light and temperature the same between the two sets of seedlings in a solution culture system can give an accurate test of water quality. Comparing growth of the seedlings between the two samples, including appearance of the root systems, can reveal any problems. Water quality issues often show as stunted roots which do not expand downwards, short, brown roots, yellowing of new leaves, stunted foliage growth, sunken brown spots on the foliage, leaf burn and even seedling death.