In the days when water was drawn from rivers, wells, and manually-operated pumps, the rainy season was a much awaited time of the year for farmers, gardeners and households.
The installation of running water systems in both urban and rural areas have somehow minimized this excited anticipation. For farmers and gardeners however, collecting rain water in drums, buckets and through modern rain harvesting methods is an essential part of planting activity.
BENEFITS OF RAINWATER TO PLANTS
1. Rainwater is a source of nitrogen.
There are three primary minerals needed by plants to grow - Nitrogen, Phosphorous and Potassium or NPK.
If you have noted number codes written on fertilizer bottles such as 10-10-10 or 20-20-10, they represent the value of these minerals that they contain. For example, 10-10-10 means 10 Nitrogen, 10 Phosphorous and 10 Potassium.
Nitrogen is a gas that cannot be directly used by plants unless it is transformed into a usable form. Rainwater contains nitrogen in forms that plants can absorb.
In his article "Why Does Thunderstorm Rain Contain More Nitrogen than Ordinary Rain?," (BBC Science Focus Magazine), Dr. Mark Lorch explained that lightning breaks the strong bond between two atoms and enables free nitrogen atoms to combine with oxygen. The resulting compound is called nitrates which stimulate and promote the growth of plants.
2. Rain water is soft water and has less salt and treatment chemicals that are found in tap water.
Using tap water either from wells or dams that are treated with chlorine or fluoride can cause a build up of salt in the soil over time and prevent the healthy growth of the roots.
Experts recommend that tap water should be allowed to stand overnight in pails so these chemicals can evaporate before using them for plant watering.
3. Rainwater is slightly acidic which most plants love.
The pH level of water (or potential Hydrogen ions) measures its acidity or alkalinity in a range of 0 to 14. Anything above 7 is on the alkaline side and below 7 is on the acidic side while 7 is neutral.
Rainwater has a pH level of between 5 to 7.
CAUTION IN HARVESTING, STORING AND USING RAINWATER
1. Rainwater can be contaminated.
While rainwater is relatively pure, it can be contaminated with dirt and bacteria especially when it flows from roofs and gutters where animal feces, dust and decayed leaves may have accumulated.
It is best to filter rainwater coming from these sources before storing them. A clean, porous cloth or plastic net can do the work.
Schedule regular cleaning of your roof and gutters at least twice a year to clear them of dirt, dust and other bacteria-causing organisms. This will also avoid the overflow of water into your ceilings during heavy rains because of clogged gutters.
Alternatively, collecting rainwater using a clean receptacle directly from the sky is a good option.
2. Rainwater should be stored in covered containers for no more than a week.
Stagnant water in open containers can serve as breeding places for mosquitoes. With the onset of rainy season, cases of Dengue Fever in hospitals are usually on the rise.
When exposed to sunlight and warm temperature, algae (lumot) which can be harmful to plants, can grow in rainwater if it is allowed to stand for longer period.
Thus, while recycled drinking water bottles may be a good idea for storing rainwater because you can view dirt or impurities from the outside, experts recommend dark containers that do not allow sunlight to pass through them.
Rainwater stored in containers and barrels are not ideal for watering edible plants like vegetables because of possible water contamination. At best, it should be used only for ornamental plants and trees.
With the ongoing rehabilitation of tap water sources such as dams and lakes, collecting and storing rainwater augments water supply for basic household cleaning, plant watering and other emergency purposes during water service interruptions.
3. Volcanic ash can affect the quality of rainwater after an eruption.
Volcanic eruptions emit sulfur dioxide into the air which can mix with water in the atmosphere and may cause respiratory ailments, skin irritations, and eye infection.
In places where a volcano erupts, residents are advised to remove their guttering systems from their rainwater storage until the alert raised for a possible acid rainfall is lifted.
When Taal Volcano erupted in January 2020, we gathered two sacks of volcanic ash from our roof and kept them for my pot-making project. To this day, the ashes have not solidified under rain and shine conditions.
What is Acid Rain?
Acid rain occurs when the pH level of rainwater falls below 5 because of the impurities it gathers as it falls from the atmosphere.
As cited in Sciencing.com, these impurities come not only from natural causes such as a volcanic eruption or decaying vegetation but also from man-made causes such as the burning of fossil fuels.
The European Statistical System (Eurostat) defines fossil fuels as a "generic term for non-renewal energy sources such as coal, coal products, natural gas, derived gas, crude oil, petroleum products and non-renewable wasters. These fuels originate from plants and animals that existed in the geological past (such as millions of years ago). Fossil fuels can also be made by industrial processes from other fossil fuels (for example in the oil refinery, crude oil is transformed into motor gasoline)."
IS IT STILL SAFE TO USE RAINWATER?
Back in the 1960's when we were growing up and environmental pollution was almost never heard about, bathing in the rain was fun and frolic that every child did not miss. We stood under the downspouts with our mouths open for a taste of soft water, swam in grassy canals by the roadside, waded in knee-deep floodwaters which overflowed from the rice paddies on the road to school and rushed to the sea to meet the first smack of jellyfishes that come out of the ocean at the onset of the rainy season.
Nowadays, there are "first flush" diverters being used by households to filter rain water of impurities like bird droppings, animal feces, dust and dirt that accumulate on the roof and gutters before the first flow of rain goes to the storage or catchment system.
For as long as the necessary precautions are observed, rainwater is safe to use for growing plants and other domestic uses, though not as drinking water unless extremely unavoidable with utmost caution and care.
It is also very important to be aware and conscious of environmental pollutants, to undertake in our own small way preventive measures at home and to participate in community efforts that are geared towards reducing acid rain and maintaining rain equality ideal for use by people, plants and animals.
It is said that life is not about waiting for the storm to pass. It is about learning to dance in the rain.
Water your indoor plants with filtered rainwater. Get your cuttings rooted in less than a month by soaking them in rainwater replaced every other day. The rainy days are also a great time to marcot expensive plants that are difficult to grow using cuttings.
Enjoy the rain while it lasts and let your plants get the benefits!
You can reach me at greencraftivist@gmail.com for any questions or inquiries.
Apple Bleza-Morales
About the Author:
Apple (or Maybelle in the corporate setting) is an HR Professional who is passionately immersed in home and community gardening as well as related arts and crafts. She completed post baccalaureate studies in Human Resources and Organization Development at De La Salle College of Saint Benilde and holds a Master's Degree in Industrial Relations from the University of the Philippines with focus in Human Resources Development.
Photos by: Maybelle B. Morales
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