How to Collect & Store Rainwater for Plants

Last Updated on April 15, 2022 by Admin

Learning how to collect and store rainwater for plants is a great way to conserve on water consumption especially during the summer.

In addition to watering the plants, you can use it for your lawn and landscaping as well.

Collecting rainwater for plants is very useful especially if your tap water is highly mineralized or has hard water. Both of which can negatively affect sensitive plants.

How do you collect and store rainwater for plants? The best way to do this is to set up rain barrels or water tanks that will collect water from the roof’s drainage and downspouts.

Make sure you filter the rainwater to remove debris and contaminants. Then secure the containers to avoid animals, insects and other objects from getting in as well.

How to Collect Rainwater for Plants & Gardening

Collecting rainwater is a good way to ensure that the water you use for your plants is safe.

Rainwater that falls from the sky is clean and it does not container minerals or chemicals.

In contrast, the water that comes from the tap has gone through some processing. In most cases, your municipality has treated the water with chemicals to make it safe for drinking.

Unfortunately, chemicals including chlorine, fluoride and a few others are not safe for plants.

While they make tap water safe for people to drink, these chemicals can cause your plants to turn yellow, brown or even deteriorate.

This is especially true with hard water or if an excess amount of minerals has been added.

Note that in most cases, there’s no problem with using tap water for your plants.

But if discoloration happens and you can’t seem to figure out what’s causing it, check your tap for water quality.

If you have a large lawn or garden, summers can be brutal as well for your water bill.

As such, using rainwater helps cut down water costs significantly especially if you can collect a good amount of water.


How to Collect Rainwater for Plants Using Rain Barrels

The most efficient way to collect rainwater for plants is to use a rain barrel. If you have a large garden or many plants, you can set up multiple rain barrels and connect them together.

This will allow you to save on water usage.

At the same time, you’ll also be able to reuse rain that falls from the sky instead of just letting wet the ground.

That said, rain barrels are not cheap.

You can expect to spend anywhere from $50 to $350 depending on the size, style, design and material used for the barrel.

I like to use plastic barrels because they’re easy to move and don’t rust or break easily.

Plastic barrels can also take a good abuse in care they tip over or something else happens.

Additionally, you can paint them to make them blend with the colors of your backyard or garden.

In addition to the rain barrel, it is also important to figure out the setup.

The best way to collect a good amount of rainwater is to take it from the roof’s downspout or drainage.

The large surface area of the roof lets it catch a lot of rain which funnels down to the pipes and downspouts.

By positioning the rain under this location, you can collect a good amount of water whenever it rains.



How to Store Rainwater for Plants & Gardening

Now that you know how to collect rainwater, it is time to store that water for plants and gardening.

Unfortunately, this part is easier said than done.

In fact, securing the rain barrels or containers to store rainwater safely is probably where you’ll take the most time when you set up your rainwater collection system.

This comes in just ahead of the collection system where you setup the drainage from the roof into the rain barrels.


Does Rainwater Go Bad for Plants?

White rainwater itself does not go bad, how you store it can make the rainwater unfit or unsafe for plants.

This is because sunlight exposure, debris, insects, animals, dust, pollution and other contaminants can easily get into the water.

As such, how you store your rainwater for plant use is just as important as how you collect the rainwater.

Unless you plan on immediately using the rainwater you just collected on your houseplants, you’ll need to know what to watch out for proper storage.



You’ve probably seen mosquitos hovering around stagnant water at some point during your life. And this is what they like to do since these bothersome insects enjoy the humidity and moisture.

What’s worse is that female mosquitos will later end up laying their eggs on the water.

This is why you can sometimes find mosquito larvae in pails or drums of water.

Any kind of hole or opening is enough for them to get in due to their size.

In addition to the eggs and larvae, mosquitos are also known for carrying viruses like dengue fever and malaria.


Dead Animals and Debris

One reason that it is very important to implement a screen filter and a cover is to prevent unwanted entry. Animals and debris can easily get into the water without these.

Thus, if you leave your tank or barrel outside without a lid or not closed completely, you may see carcasses of insects or other animals.

Leaves, droppings and other debris can also find their way in there.

Decaying matter along with maggots and other nasty things can damage your plant and its roots.


Pollution Contamination

Pollution can likewise get into the water. Here, air pollution as well as other chemicals may find their way into the barrel or tank you use to store the rainwater.

In some cases, it will make the water dirt. Other times it can change then pH level.

Yet there are times that chemicals and other contaminants can end up there.


Algae Growth

Algae cells are present in the air. And in the presence of the sun and water, it will grow and become the green layer that you see grow out of nowhere on the ground or walls.

This can happen to water inside barrels especially if the sunlight can penetrate the exterior.

As such, a dark opaque container is always better than a translucent one.

Unfortunately, once algae develops in the water, you don’t want to use that water for your plants.

Algae are plants. As such, they will grow on photosynthesis just like your plants do. And if you use algae-contaminated water on your plants, it could block the absorption of water to the roots.

Algae can also cover the leaves.


Should You Dispose of Contaminated Rainwater?

My recommendation would be to throw the contaminated rainwater away safely.

While this would be a waste, it would be better than damaging your plant.

The most important rule is NEVER to use contaminated rainwater on plants you plant to consume. This includes vegetables, fruits and herbs.

This will make the plants toxic and put you and your family in danger.

Since you don’t know what the water is contaminated with, it is also not a good idea to use this kind of water on ornamental plants or grass.

Although technically you could.

The downside is that it can cause stunted growth, abnormal development, discoloration or even kill your plant.

As such, it is just not worth the extra risk.

Therefore, the best way to make sure that your collected and stored rainwater is not infected is to keep it secure.

Additionally, inspect the water before using it.

There should not be anything in the water. Also, take a whiff of the water. If there’s any kind of funky smell, don’t use it.

It should smell like normal, safe water. In short, no small.

Foul or unpleasant smells are always a warning sign not to use it on your plants. Of course, you can still use to wash the driveway or remove dirt on concrete and things like that.

Before using the rainwater, also check the water pH levels first.

Rainwater should have pH between 4.5 to 5.5.


Best Ways to Keep Rainwater Clean and Fresh for Plants

Since contaminated rainwater is no good for your plants, it is very important to put the right safeguards in place so that contaminants are kept out.

This way you maintain clean rainwater.

Clean rainwater not only is useful for your plants, it also stores much longer.


Secure Your Rain Barrel or Rainwater Collection Tank

The first step in ensuring clean rainwater for your plants is to use a secure container.

You can use a large tank or a smaller container. The size is really up to you and what your plants’ watering needs are.

Whichever you go with, make sure there’s always a lid or cover that can be sealed tightly.

This prevents animals, insects and even debris from getting into your barrel or tank.

I like to use a plastic container.

Not only are these cheaper, they are lighter to move as well if you need to transfer them. Avoid using metal containers which rust. Concrete are very heavy and can crack over time.

Also, make sure the container is opaque with a dark colored exterior.

Sunlight exposure is bad if it gets to the water. Therefore, use material that will block light from getting in the stored rainwater.


Install a Filtration System

The most efficient way to collect enough rainwater is to position your barrel, tank or container near the roof drain.

Since the roof, pipes and gutters can have all sorts of things including dust, debris, droppings, leaves and other contaminants, it is important to add a filtering system.

You can put this at the end of the downspout from the roof or at the opening of your barrel or tank.

This way, the contaminants are filtered before the water enter the tank.


Regularly Clean the Containers

A properly secured barrel, tank or container needs less cleaning. But you’ll need to do some cleaning maintenance once in a while to keep things tidy.

However, if you use bucket or containers without lids, you’ll need to clean them regularly.

This can vary from once a week to even twice a week depending on how much dirt can develop.

Just clean the buckets or containers with liquid soap or dish soap along with water.


Keep the Barrels Out of the Sun

Try to find a spot that’s shaded. Usually, downspouts are under some kind of roofing. And they are attached to the walls of homes.

This helps keep them out of the sun.

As such as possible, try to keep the barrels from the sun.

If you can’t completely keep it out of sun exposure, use a black, brown or dark blue barrel that won’t allow the sunlight to pass.

You can also paint the exterior of the barrel with dark colored paint to prevent light from getting to the water.

The downside to dark colors is they absorb heat. This can warm up the water.

Additionally, mosquitos are attracted to warm water and promote breeding among these insects. Thus, if possible, keep the barrel in a shaded location or set up something that will block out the sun and put it around the barrel.


Keep Mosquitos Away

Mosquitos are good at detecting standing bodies of water. As such, they can still find and stay around your rain barrel.

The good news is that there are ways to keep mosquitos away.

One is put mosquito repelling plants near the barrel or water collection container. Potted plants work well as you can move them around easily.

You can likewise use certain oils whose smells repel mosquitos.

Just coat the exterior of the barrel by spraying on the oil mixed in with some water.


Use Chlorine Tablets

Chlorine tablets used to aquariums also come in handy.

Here, they function similarly as to how they’re used in aquariums, to prevent algae growth.

This keeps rainwater safe to use for plants.

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