These digital pH pens are a cost effective way to read the pH of any water, for orchid culture this is important as the majority of orchids prefer a pH between 5.5-6.5. Some orchids prefer lower or higher than this so doing a little research enables you to tailor the growing conditions producing the best results, however between 5.5 - 6.5 will achieve good results for most.
pH is a standard measurement of a solutions acidity or alkalinity. A baseline, neutral pH is 7; anything rated above a 7 is alkaline, and anything below a 7 is acidic. pH can be easily measured using a pH pens/meter or testing strips.
pH of water is important for many other aspects in life and not only specific to orchids.
Other uses include
hydroponics, plants, fish keeping, ponds, swimming pools.