How To Make Tap Water Safe For Plants

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Growing plants is a great way to relax and get in touch with Mother Nature without leaving your home. Oddly enough, there are several cold wars (and some quite heated debates) among plant enthusiasts. One of the most infamous of these is the question of using tap water.

Tap water can kill some plants and directly or indirectly harm others, although these effects often go unnoticed. Here’s everything you need to know about tap water, the ongoing debate, and how to make tap water safe for plants.

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How to Make Tap Water Safe for Plants

Tap water contains numerous substances that can harm your plant in various ways.

Purifying the water before use is strongly urged.

The Great Tap Water Debate

There are a couple of perspectives regarding the use of tap water.

Pro-tap enthusiasts claim that the water doesn’t harm plants, often pointing to their plants as examples.

This group rarely acknowledges potential harm to plants and tends to have the most extensive presence in online plant guides.

Some more moderate opinions note that the water can hurt some plants with long, thin leaves and that chlorine or fluoride can harm many plants.

They also acknowledge the risk of mineral buildup but state that some components of tap water can be healthy for plants.

The third group in the debate state that tap water is just plain wrong and should not be used.

They reference natural alternatives and effects that the other groups rarely mention, such as stunted growth.

Oddly enough, very few anti-tap users don’t usually include basic instructions for making tap water safe in the event the grower doesn’t have a safe water supply.

What’s In Tap Water?

Tap water is not pure, and many mineral and chemical additives can vary from one municipality to another.

The most apparent additive is chlorine (and a similar product, chloride).

Chlorine is a toxic chemical that’s added to kill microbial life, reducing the risk of contracting diseases from drinking water.

While chlorine can harm humans and pets in quantity, plants are often far more sensitive and can suffer chemical burns or other problems when exposed to chlorine and chloride.

Another toxic substance is fluoride.

Many municipalities began adding fluoride, thinking it would help prevent tooth decay, but this effort proved futile.

Additionally, it has since been determined that fluoride can be highly toxic to humans in quantity,

Plants have a higher sensitivity, and fluoride can seriously damage many plants.

Many municipalities inject chemical cleaners and those listed above to sanitize the water further.

These chemicals, especially more sensitive ones, can harm plants and are usually added to soften hard water.

Finally, we have the mineral content. Calcium, magnesium, nitrates, and phosphorus can be healthy for plants in moderation.

However, other minerals, such as iron, are just plain bad for plants.

It should also be noted that too much calcium can clog roots and prevent the plant from being able to absorb water and nutrients.

Making Tap Water Safe

One of the biggest arguments pro-tap guides give for using tap water is that people can’t always get access to healthier sources.

Gathering and storing rainwater is free and easy, but there are admittedly times (such as droughts) where this isn’t an option, and you don’t have the time or funds to buy some distilled water.

The good news is that you can make tap water safe for your plants (and healthier for you) with some preparation.

Here are two easy ways to purify tap water at home.

Distilling Method

Sometimes referred to as the boiling method, this is one of the oldest methods for purifying water and one of the cheapest.

Fill a kettle or stock pot with water and set it to a boil.

When the kettle goes off, pour it into another container, preferably without opening the spout.

Using a stock pot, let it come to a roiling boil before pouring the water out.

In either case, calcium from limescale and other minerals will stick to the sides of the pot and can be rinsed out once the boiling water is removed.

You can add the water back on and bring it to a boil more than once if you have hard water.

This isn’t as efficient as distilling, which involves two lidded containers with a connecting tube.

As the water in one container boils, the steam passes through the tube and condenses into the other, effectively removing ALL mineral content.

However, boiling the water will still remove any water chlorine, fluoride, chemicals, and excess minerals.

Please ensure the distilled water is left to cool overnight and is at room temperature before using it to water your plants.

Also, remember that distilling your water requires the use of the stove, so there is some negligible cost involved.

However, you can kill two birds with one stone if you’re making rice, boiling potatoes or other vegetables as long as you don’t add salt. More on rice water for plants.

This water will still have the chemicals and excess minerals removed but will be infused with nutrients from the vegetables, which can be beneficial to most plants (warning: carnivorous plants can be harmed by this infused water, so never use vegetable water on a Venus flytrap or pitcher plant).

Sit And Filter Method

Chances are you have a home filter or have thought about getting one.

Brita and other companies make great filters that can attach directly to the tap.

However, a Zero Filter pitcher is one of the best when dealing with minerals.

These pitchers come with a digital tester and can effectively filter out all minerals for a month of regular use before the filter needs to be changed.

Not only does this make them suitable for plants, but it can also make water safer for babies and pets.

The sit and filter method is a two-step technique that requires up to a day (but a minimal effort on your part).

The first phase is to fill a container with tap water and let it sit out.

Depending on the quality of your water, you can let it sit for as little as 8 hours but may need to leave it to sit for up to 24 hours.

This allows the chlorine gas to escape and removes fluoride, which will evaporate.

Next, pour this water into your filter pitcher and let the pitcher do its job.

This step removes most or all of the minerals, depending on your filter.

Once both steps are completed, you’ll have something similar to distilled water.

Bonus Tip: Emulating Rainwater For Better pH

One last point about tap water is that it’s often alkaline due to its calcium content.

As most plants need a pH level between 5.5 and 7.0, alkaline water can be harmful.

You can solve this by adding a couple of teaspoons of mild vinegar (apple cider vinegar is usually milder than white vinegar) or hydrogen peroxide to your purified tap water once per month.

This amount is small enough that it won’t harm the plants (don’t get vinegar on their leaves), and it can help maintain the acidity (and, in the case of the peroxide, it has the same ionization benefits as rain water).

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