Rainwater can be a better option for your garden. It has fewer harmful minerals, contains more Nitrogen than tap water, and is naturally acidic which plants love.
This doesn’t necessarily mean tap water is bad for your garden. Tap water in most cases will work just fine, it’s simply that rainwater has a number of properties that make it a better option if it’s available to you. Here are the three main reasons that rainwater are a better option for a lush and productive garden.
Rainwater helps create an acidic pH in your soil
The pH of soil is a critical factor to manage when gardening and in most cases, plants prefer a pH that’s slightly acidic. The ideal pH for most plants falls within the range of 5.5 and 7. This is largely because the bacteria that releases Nitrogen from organic matter operates best in this range and Nitrogen is a critical nutrient for most plants.
Fortunately, rainwater is slightly acidic with an average pH of about 5.7 meaning it is perfect for your garden. Tap water tends to be treated and, more often than not, will be more base (the opposite end of the pH scale) with a pH around 6.5 to 8. When the pH of the soil for your plants is too high, it can prevent your plants from absorbing certain nutrients.
Tapwater has unnecessary minerals
Tapwater is great for drinking but may not be as good for plants. In order for your tap water to be drinkable, it needs to be treated so that harmful elements can be removed. Unfortunately, for your garden these may not be helpful.
The most common elements in tap water are Calcium and Magnesium, things that are commonly found in hard water. If you’ve ever had or seen white scaling on faucets or soap scum in your tub, that is a side effect of hard water. Ultimately, excess levels of Calcium and Magnesium don’t mean you’re garden will struggle but it will mean that you may have to change the soil more often or manage the pH.
Other elements are only issues in fringe cases. Chlorine, which is commonly used in treating municipal water, isn’t shown to have a significant effect on a plant’s ability to grow. Fluoride is also a common ingredient in municipal water districts and only has a negative effect on certain plants that are sensitive to it.
Rainwater contains nitrogen
Most importantly though is the fact that rainwater carries more Nitrogen with it, one of the most critical nutrients to a plants health. Over three-fourths of the Earth’s atmosphere is Nitrogen and rainwater absorbs some of that as it collects and falls. Additionally, it falls in a form that’s easy for your garden to absorb: liquid.
The amount of Nitrogen that rainwater absorbs can increase though. Believe it or not, a thunderstorm can make a huge difference. The energy produced by lightning helps break the bonds of the atoms in Nitrogen gas enabling more of the free atoms to bond with the Oxygen in the atmosphere.
In the end, rainwater holds a few advantages of tap water that will mean your garden will be greener and your yield will be greater. If you aren’t already collecting rainwater, you should consider a catchment barrel at least to water your plants. Otherwise, tap water will be fine.