Most gardeners want a slightly acidic pH because it makes nutrients more available to plants and is better for overall soil health. Here, rainwater could be your friend (pH 5,. Tap water is more alkaline (between 6 and 8 pH), depending on where the drinking water originates. Drinking rainwater has not been shown to be more beneficial to health than drinking other sources of clean drinking water.
Water is water, right? Is everything practically the same? Surprisingly, that's not the case. Water that falls in the form of rain is very different from that coming out of the tap in your house. It has not collected any minerals or salt from the soil and has not been treated with chemicals. While useful for many things, rainwater isn't as pure as you might think, so you can't assume it's safe to drink.
Rain can carry different types of pollutants into the water you collect (for example, bird droppings on the roof could end up in the barrel or water tank). Rainwater can carry bacteria, parasites, viruses and chemicals that could make you sick, and it has been linked to disease outbreaks. A number of factors can affect the safety of rainwater, including how often it rains in your geographic area, levels of air pollution, and the methods and tools used to collect, treat, analyze and store water (. Rain contains few salts, minerals, treatment chemicals, or pharmaceuticals that are often found in municipal tap water.
When rainwater is used as a source of supplemental water, homeowners should ensure that rainwater cannot enter pipes that contain drinking water. When you irrigate with tap water, either well water or municipal water, salts and chemicals can build up in the soil of indoor plants. You can choose to have a whole-house system installed, or you can choose a countertop water filter or an under-sink water filter, which can provide you with the clean drinking water you need. You get the benefits of treatments performed by the water company, which improve the safety of water that originally fell as rain and is found naturally.
If you collect rainwater from your gutter or from a rain barrel, through the roof, the water can contain traces of contaminants from your roof, especially if you have composite shingles, as well as contaminants from bird droppings and other creatures, such as squirrels, that may spend time on your roof. No matter what type of water you use to water your indoor plants, make sure it's at room temperature to avoid stressing your plants' root systems. So what water is best for your plants? The things that fall from the sky or the water that comes out of the tap? The best way to get tap water that is free from the effects of chlorine and additives and minerals is to use a water filtration system. Long-term irrigation with water that has higher levels of chloride (and, to a lesser extent, fluoride) can also prevent the plant from absorbing available nitrate.
Consider adding a grate to the water inlet or emptying the rain barrel at least every 10 days to prevent mosquitoes from using the rain barrel as a breeding ground. Accumulated rainfall is usually naturally slightly acidic, so it can help remove buildup of accumulated substances from alkaline tap water deposits in potting soil.
