It turns out, there’s a lot of difference. If you’ve watered your plants by sprinklers or watering can, you may notice that your plants are not looking as good as if they had the same amount of water from the heavens.
One reason is that tap water contains chlorine.
Almost all plants are susceptible to chlorine toxicity. This may lead to burnt leaf margins.
It also contains fluoride.
Fluoride toxicity shows symptoms of burnt, discoloured, or spotted leaves and even stressed fruit which becomes susceptible to disease. Indoor plants such as Dracaenas, Yuccas, Spider plants (Chlorophytum Comosum, Fruit trees and Pines are particularly prone to this.
Hold on, there’s also sodium.
Sodium is used as a water softener to stop calcium and magnesium turning hard and damaging pipes. Whilst all of these minerals are found in rainwater, they are at a much lower concentration and in these quantities do not do your plants any good. The high sodium, like chlorine, is toxic to plant tissue. The high Calcium and Magnesium content may also leave white sediment on your plants’ leaves.
Sodium also damages the soil structure. Rather than soil clumping together, the Sodium disperses it and creates cracks on the surface of the soil.
The Benefits of Rainwater.
Nitrogen is essentially what makes a plant stay green and healthy. Some of it comes down with the rain and is taken in by the plants by its leaves and roots.
Oxygen is more prevalent in rainwater than tap water. Without getting into too much detail (boring), this ultimately means that the soil is less likely to get waterlogged and kill your plants with root rot.
Carbon Dioxide is bad for us animals, but plants love it. Rainwater has a higher carbon dioxide content which then gets absorbed by the plants and ultimately allows the plants to create energy and release oxygen.
Rainwater also falls evenly over the garden so as to not miss a patch when watering from a can or sprinkler system that doesn’t quite reach that far corner.