Rainwater is generally an excellent source of irrigation for plants. Plants are not only watered when it actually rains, but rainwater can be collected in buckets and barrels for later use. In fact, commercial rain collection containers have a spigot and hose attached for easy watering. Collecting rainwater and watering your plants with it is a good idea all year long, but stored rain water is especially invaluable during times of drought and water restrictions.
Most rainwater is clean and gives plants water free from chemical additives, such as chlorine or salt, found in tap water. And because it's free to collect rainwater, plants are more likely to be watered more often than in homes where city water can be costly or restricted.
Clean rainwater seeps into the soil and washes salt--which is not healthy for plants--deep into the ground away from the roots. As an added bonus, plants are then able to absorb more water, which reduces their overall need for irrigation.
Raises Soil Acidity
Acid rain has a pH level below 5.6 often caused by air pollutants but also by natural sources such as volcanoes. More acidic soil can slow down plant growth and damage foliage. To find out if acid rain is an issue in your geographic region, conduct a search on the Environmental Protection Agency's website. Then talk to your local county extension office to remedy the acidic soil with fertilizer.