Have you also wondered, “what are the benefits of rain water for plants?” Because I certainly did when I first started gardening. I have been gardening now for a while and it’s almost every day that it rains here in the UK. I thought better start collecting rainwater for my indoor and outdoor plants.
Rainwater is used as an alternative in watering plants because, aside from rainwater being free, it has many benefits.
In general, Rainwater provides more nitrates which help your plants grow bigger and become leafier and more oxygen to make them healthier. According to Charles and Rode, the average pH of rainwater is 5.6. The slight acidity of rainwater and the number of carbon-free nutrients locked in the soil is what the plants love. So whether indoor or outdoor, your plants will surely love rainwater.
Read on as we unveil why plants crave rainwater.
What are the components of rainwater?
A study by Hutchinson in 1957 showed that rainwater is a mixed electrolyte. See his book here. You have to know that when minerals dissolve in water, it produces charged ions – negative and positive. These are your electrolytes which are very important. Rainwater has major ions and minor ions.
The major constituents are the following – sodium, bicarbonate, magnesium, calcium, chloride, potassium, and sulfate. They are usually combined with nitrogenous compounds such as ammonia, nitrate, nitrite, and nitrogen.
The minor ions include iron, bromine, boron, iodine, silica, and alumina. Other components are added depending on your location such as dust particles, sand, and pollen, among others.
Water electrolytes are essential because they help plants balance their mineral concentration. In other words, electrolytes help plants boost critical processes such as photosynthesis. Photosynthesis is the one responsible for creating energy for plant growth and maintenance.
What are the benefits of rain water for plants?
Rainwater is safe. Rainwater is purely soft water. It means rainwater does not have the minerals, salts, chemicals, or pharmaceuticals that you usually find in tap water. Groundwater, like tap water, is also not beneficial for plants. Sometimes they are even harmful due to the accumulation of chemicals throughout the years. Do not worry if you mistakenly use tap water or groundwater for your plants, just flush the toxic chemicals using rainwater.
Rainwater contains vital components. Rain has an essential macronutrient for plants which is nitrate. Nitrate has nitrogen which the plants need to survive and have leafy foliage. There are other types of nitrogen sources available in the market, but plants do not readily absorb most. So, if nitrate is the most readily bio-available, then why not just collect rainwater?
Rainwater liberates other nutrients in the soil. Rainwater has thousands of carbon-containing compounds. Together with rainwater water’s pH level, these compounds unlock some micronutrients found naturally in the ground, such as magnesium, zinc, etc. These micronutrients help in plant growth and development.
Rainwater prevents chlorine toxicity. There are times that your plants look burned or scorched on the tip. It is most likely due to excess chlorine in tap water during the purification process. Remember, rainwater is free from chlorine, so it would be wiser to use this to prevent toxicity.
What is the pH level of rain water?
Rainwater has the perfect pH level for watering your plants. Rainwater is slightly acidic with a pH of 5.6, and guess what the ideal pH level of the plant is? That’s right – acidic at around pH 5.5 – 6.5. Water that is too acidic or too basic such as groundwater and tap water, is extremely harmful to plants as it may cause a buildup of salts that can burn the roots, preventing them from absorbing moisture and minerals.
Read more: 15 Best Plants for Leca and Semi-Hydroponics Growing
Can the environment make rain water too acidic?
Yes, rainwater can become too acidic due to pollution. Again, rainwater is naturally slightly acidic. However, when rain reacts with sulfur dioxide in the air, it can become too acidic, producing what we call “acid rain.” Acid rain has a pH of around 4.2, which is too acidic for most plants. This will endanger not only most plants but also other living organisms.
Do not worry because acid rain is only evident in places near power plants, factories, or basically areas where sulfur dioxide and nitrogen oxides are produced in large amounts.
Your plants would also be safe from acid rain because of the soil. Your plants’ soil can neutralize the acidity of the acid rain by flowing through it. It depends on the thickness and composition of the soil. The thicker the soil, the more it neutralizes the acidity.
What are the effects of rain water on plants?
Plants are greener. Nitrogen makes plants green, and since nitrogen is the most abundant element in the air, plants look greener after rain. The macronutrients, mostly nitrate, come down in the rainwater and are immediately absorbed by plants.
Plants are healthier. Rainwater also contains more oxygen which makes your plants healthier. The amount of oxygen also acts as a safeguard when there is excessive rain. Overwatering the plants may cause your plant’s roots to rot. However, since rainwater is highly oxygenated, it allows a continuous exchange of nutrients, preventing the roots from rotting.
Do plants grow faster on rain water?
Yes, plants grow faster and are more extensive. Although it would depend on the type of plant, as some do not allow too much growth, plants watered with rainwater are generally bigger, and they grow faster. It is because rainwater removes salts and other chemicals beyond the root zone where they usually accumulate. Again, these salts inhibit plant growth. When these salts are flushed through the soil, the development of plants is more prominent and evident.
How do you store rain water for plants?
Technically, you can store rainwater with any open container just sitting outside during a rain, but here are four methods you can try to harvest rainwater.
1. Barrel Harvest
Barrel Harvest is the easiest to do and the easiest to set up because you only need a barrel. What you have to do is to place the barrel directly below your roof pipes and just let the water drip. Now, if you do not have a barrel, you can use any container that can hold a huge volume of rainwater.
2. Fix Roof Harvest
The Fix Roof Harvest method is almost the same as the Barrel Harvest. The only difference is that roof piping, using an extension pipe, is directly connected to a huge tank, bigger than the one in the Barrel Harvest. Fix Roof Harvest is more suitable for places where rain does not occur regularly.
3. Underground Harvest Tank
In this method, rainwater is collected using underground tanks. The underground Harvest Tank method is permanent and uses a massive tank. Same with the first two methods, just connect the roof pipes to the underground tanks and let nature takes its course. Underground Harvest Tanks are more suitable in places with little rainfall.
4. Recharge Pits
Here, you are not actually storing water in a barrel. Instead, you are improving the groundwater levels. What you need to do is to dig a pit near your garden and put pebbles in it. The depth of the pit depends on you – the deeper the pit, the more water it holds. The pebbles allow fast movement of water. Then, from your roof pipe, extend it to the point where it drops water into the pit.
How to increase the shelf-life of rain water?
Typically, you can only store rainwater for a week because it tends to become contaminated. You can indefinitely prolong the shelf-life of your stored rainwater by avoiding animal and insect contact and keeping it out of too much light. You may consider the following.
- Use a proper barrel or tank. The size of the barrel would depend on your needs, but you have to make sure that it is properly covered, it is tightly sealed, and it is made up of ideal materials. You must avoid metal tanks because they rust. You can use plastic barrels because they are durable and blocks out light, ensuring no algae growth.
- Use filter. Since most rainwater is collected from your roof, there might be some contaminants present such as leaves, bugs, dust, etc. Do not forget to regularly clean and de-clog the filter.
- Clean the containers regularly. If your barrel does not have a lid, make sure that you clean it often. Ensure that there is no algae growing and mosquito breeding inside. You can use dishwashing liquid. Just make sure that you rinse it well.
When does rain water become bad for plants?
One problem that usually occurs with stored rainwater is algae growth. The presence of algae will make the harvested rainwater unusable for your plants.
Algae thrive in warm temperatures. That is why you must not expose your barrel to too much sunlight.
Effect on plants: If you use rainwater with algae for watering, the soil of your plant may develop layers of algae which will prevent water go to the roots. In other words, algae growth deprives your plants of the nutrients they need and also decreases the soil’s oxygen levels.
Another problem is contamination from air pollution, which we have already established. When rain reacts with sulfur dioxide and nitrogen dioxide in polluted cities, it may cause acid rain.
Effect on plants: Plants thrive at pH 5.6, and acid rain has a pH of around 4.6. Since the acid rainwater is too acidic, the exchange of nutrients between the roots and the soil is affected, negatively affecting plants’ growth.
Contamination from animals may also occur. When your barrel is loose, animals such as frogs may enter, die, and contaminate the water. The dead body in the tank attracts flies and produces larvae.
Effect on plants: Aside from making your garden smell awful, you are also transferring larvae to your soil which may interfere with your plants’ root system.
Lastly, your barrel might be a mosquito breeding centre. If your rainwater storage tanks have small openings, it will allow female mosquitos to enter and lay eggs.
Effect on plants: Yes, they may not be harmful to plants, but they sure are detrimental to humans, to you! Mosquitos may carry diseases like dengue fever and malaria. You also must remember that plants can serve as an ideal breeding ground for mosquitos.
Should I throw away contaminated stored rain water?
Using contaminated rainwater on vegetables can cause them to be harmful to consume. You may water ornamental plants with contaminated rainwater, but this may result in irregular growth or death of the plant.
How to check if rainwater is still okay?
- Check for the unpleasant smell. If it smells awful like a rotten egg, dispose of it. A change of odour is a sign of bacterial contamination.
- Test the pH level. If your stored rainwater is contaminated by acid rain, it will have a pH level of around 4.3, which is not suitable for plant growth. The pH needs to be around pH 5.0 – 5.6.
Is rain water better than tap water?
Rainwater is better than tap water. Actually, rain water is the best for your plants. Like what we discussed earlier, rainwater contains more oxygen which helps plants grow healthier. It also has a lot of benefits compared to tap water.
Rain also pours uniformly, so no plant is left out. Also, rainwater will wash off deposits and dirt covering the leaves, making photosynthesis more efficient and your garden look more beautiful.
What is the alternative to rain water for plants?
While there is no better water for your plants than rainwater, you can use bottled spring water as an alternative. Even though it is impractical due to its cost, bottled spring water does not have those harmful chemicals found in tap water. It will definitely help your plants grow greener and healthier. It is basically the same as rainwater minus some nutrients naturally found in the environment. Plus, rainwater is free, and bottled spring water is not.
What about distilled water for plants?
Distilled water will not harm your plants. It will keep your plants alive, but your plants won’t really grow as quickly or as healthy as plants watered with rainwater or bottled spring water. And please do not also add salt, sugar, or other nutrients to your distilled water. Remember that anything with sugar and salt is harmful to your plants.
I hope that helped you to understand the benefits of rain water for happy plants! So you better start collecting it too!
ABOUT THE AUTHOR:
Zany Plant World
Succulent and Houseplant blogJoin me in exploring the beautiful and colourful world of succulents and houseplants, one plant at a time! Zany Plant World blog aims to help newbies and fellow plant enthusiasts grow healthy and happy succulents and houseplants at home. Turning your house into an urban jungle oasis that can give you the zen vibes that we all need in this crazy and busy life.