I see that some plant water recommendations state that rainwater should be used. I was just wondering why that is?
Some plants are sensitive to tapwater's chemical additives, such as fluoride and chlorine. Dissolved chlorine reacts with soil elements to create chloride compounds which damages the cells and leaves browning tips. It's toxic to plants in high enough concentrations. Rainwater carries macronutrients and lacks the chlorine so it's often the better choice for more delicate species. It's worth noting that the pH is often slightly more acidic and "softer" when compared to tapwater which is generally more neutral.
Hello Lau. Thanks for the explanation. So could there also be the possiblity of rainwater adding too many nutrients?
Hi, yes its possible that the composition of the water can have excess nutrients. Also if you dont regularly clean out the guttering and water butts etc. you can get algae and detritus, so some maintenance maybe required.