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What Is Soft Water & How to Soften Hard Water for Plants?

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All plants need water in the required amount for growth.

As an essential reactant for the process of photosynthesis and a need to transport minerals and nutrients throughout the plant body, properly watering your plants would ultimately result in proper plant growth.

Water also helps in maintaining the turgidity of plant cells.

Most of us wonder which water is best for our plants. Will these gorgeous little buddies thrive in soft water or hard water?

Primarily, soft water has beneficial effects on plants. On the other hand, hard water can be harmful to your plants. Most gardeners tend to change hard water into soft water before giving a shot of hydration to their plants.

Still, many of us don’t know what is soft water and how to soften hard water for plants.

Today in this article, we will go through this very topic. So, if you are also wondering, “What is soft water and how to soften hard water for plants?” then stay with us till the end of this debate so that you can get a satisfying answer.

Hard water comming out of tap. What Is Soft Water and How to Soften Hard Water for Plants
What Is Soft Water and How to Soften Hard Water for Plants? – Image via Silvan Schuppisser.

What Is Soft Water and How to Soften Hard Water for Plants?

First of all, let’s get an answer to “What is soft water?”

Water having a low composition of minerals in it is called soft water. Soft water has valuable properties for plants because of its low calcium and magnesium ions and higher sodium content.

Soft water feels smoother to touch than hard water, but it tastes salty because of its high sodium concentration. Soft water also makes soap to lather, and it occurs naturally in rainwater, glaciers, ponds, and lakes.

That’s also a reason that using rainwater is valuable for your plants.

If someone asks you what is soft water, simply tell them that the term is often used to describe the water created by the water-softening process.

We’ll head towards the process. But, before letting you know how to soften hard water, let us take a look at hard water.

What Is Meant by Water Hardness?

Water is the universal solvent because it dissolves many substances. As water passes through the rocks, it picks up naturally occurring minerals and metallic ions. Water containing any quantity of dissolved metals is called hard water.

Magnesium and calcium are the common elements picked up by the water. The amount of these minerals in the water sample determines the hardness of the water.

Although these minerals wouldn’t directly affect the overall health of your plant, they would leave insoluble salt deposits in the soil, making it unsuitable for plants.

Is Hard Water Suitable for Your Plants?

Most houseplants don’t really thrive in hard water. Hard water may work for some plants, but it leaves behind plenty of calcium and magnesium carbonates in them. Moreover, hard water may have some severe effects on your plants.

Hard water affects plants in various ways:

Scaly Leaves

The minerals in the hard water can make the plant leaves scaly and leave some chalky residue outside the leaves from where water is absorbed and transpired.

When scale covers the leaves, it is difficult for the plant to breathe, and also it becomes harder to get sufficient sunlight for the plant.

Suppose you see any chalky deposits on the leaves. In that case, you can remove them with a mixture of water and acidic components like lime water — also known as Clark’s method — and vinegar or acetum.

Calcium Carbonate Coats the Soil

In some areas with heavy minerals in the water, you may notice a greyish-white powder deposit on the soil. You can balance the minerals with alternate soil and fertilizers, but it is better to use filtered, distilled, or soft water.

Excess Minerals in the Soil

The amount of salt and minerals in the soil controls how much water the plant absorbs. If there are excessive minerals in the soil, the plant cannot drink the water and remains dehydrated.

The wrong balance of minerals in the soil can cause a change in the growth pattern and health of the plant. It would be best never to allow hard water to mix with your plant’s potting mix.

As hard water has a lot of poor effects on plants, it is better to convert it into soft water.

What Is Soft Water and How to Soften Hard Water for Plants?

You have already got the answer to “What is soft water?” Let’s now look at how to soften hard water for plants.

Soft water promotes the healthy growth of plants as it balances down all the minerals and ions.

Hard water has a high pH value, which means it is alkaline. If your plant shows signs of suffering, like pale yellow leaves due to hard water, it is better to use acidic fertilizer.

There are some areas with a high amount of minerals in the water. If you live in such places, you have to take simple steps to convert that hard water into soft water.

Softening of hard water can be done through natural methods or using a few chemicals and filtration methods. So, let’s look at how to soften hard water for plants.

Sea water. What Is Soft Water and How to Soften Hard Water for Plants
What Is Soft Water and How to Soften Hard Water for Plants? – Image by Stephane Hurbe.

Natural Methods

There are some natural methods of converting hard water into soft water. Some natural and reliable ways of softening hard water are:

  • Use of Volcanic Rocks: Volcanic rocks are the best natural method of water softening. As the hard water passes through the porous surface of volcanic rocks, it filters calcium and magnesium carbonates leaving behind only filtered soft water.

Pro tip: A simple way of using hard water for plants is to leave it out in the open for 24 hours before giving it to the plants. This step removes chlorine and lead from water and diminishes their harmful effects.

  • Boiling hard water is the quickest method used for water softening. Boiling also removes many harmful additives from water.

Now, I don’t need to explain how to boil water. 😅

Chemical Methods

The chemical method is the most inexpensive way of softening hard water. Some of the most common chemicals used in water softening are borax, slaked lime, sodium carbonate, etc.

  • Washing soda or sodium carbonate can soften the water with temporary or permanent hardness. Sodium carbonate dissolved in water releases carbonate ions which react with the dissolved calcium and magnesium ions, removing calcium and magnesium carbonates from the water and making it soft.
  • Vinegar has acidic nature and is highly beneficial in water softening. You have to add one tablespoon of vinegar to every three cups of water to remove temporary hardness.

But using these chemical methods proves to be harmful to plants. Thus, these methods are not recommended for softening hard water for plants.

Filtration Methods

Some filters easily convert hard water into soft water without any effort. Some common ones are:

  • Filter pitchers are the best choice for softening hard water because they remove all the contaminations and many bacteria and viruses from the water.
  • A reverse osmosis system is also a filtration method that removes filtrates and impurities from the water by running water through carbon filters to reduce the presence of salts and minerals.
YouTube: AllAboutWaterFilters.

Effects of Using Soft Water in Plants

Besides all the benefits, soft water can also have some harmful effects on plants.

  • Soft water is not ideal for plant watering. It is not good to use soft water in your garden in some specific cases because of the high sodium concentration.
  • Soft water is slightly acidic also, so it is better to know if your plant like an acidic environment or not.
  • Soft water can cause some plants to deteriorate or even die. It can also affect the soil and make it difficult for your plant to get enough moisture.

How to Reduce the Effects of Soft Water?

Rainwater is best for your lawn that’s why providing soft water from rain proves to be very beneficial. If you have distilled water or collected rainwater, you can mix it with soft water to better grow your plants. The dilution reduces salt concentration in water.

Rain drop falling on hand. What Is Soft Water and How to Soften Hard Water for Plants.
What Is Soft Water and How to Soften Hard Water for Plants? – Image via Fabiano Rodrigues.

You must avoid using soft water in your garden during the dry period because it builds up sodium levels in the soil and causes the plants to die of thirst.

Also, if your garden and pots are well-drained, there should be less sodium build-up. Therefore, always use the best potting mix for your plant type.

  • Do not use any chemical softener method for your garden. It has remains of additives that also affect your plant growth.

It will help you if you use these simple tips for watering your plants:

  • Use a water barrel to collect rainwater for watering your plants.
  • Use bottled water for your indoor plants.
  • Do not use excessive softened water on indoor or outdoor plants.

How to Treat Soil Affected by Soft Water?

If your soil is affected by using too much soft water, you must do some work to neutralize the level of salts in the ground. There are some standard methods you can use to nullify the effects of salt.


Leaching is the most common method to reduce salts in the soil. You can also use it to treat soil affected with hard water as well.

  • In this method, you have to pour a large quantity of water into the soil. It is better to use water with less salt concentration for this purpose.
  • Leaching will draw out excess minerals from the soil and wash them away. But it may also draw the required nutrients from the soil. Therefore, the best method to fix up the soil is still re-potting your plant in a proper soil mix.

Limiting Transpiration

Decreasing evaporation from the plant surface can also help you reduce salt concentration in the soil. You can reduce the effect of evaporation by adding a mulch or residue to the ground.

By reducing the evaporation process, the water level in the soil remains sufficient to dilute the salts present in the soft water.

Pro tip: On the other hand, watering more frequently can also help dilute the soil’s salt concentration. But you have to be careful not to overwater your plant. Overwatering means waterlogging combined with poorly-draining soil, leading to root rot. Therefore, along with a suitable potting mix, it is always best to use a pot with many drainage holes at the bottom.

You can browse through this article to learn all about root rot and how to treat it.

Chemical treatment

Gypsum is the most common element used for the chemical treatment of the ground. It is not commonly used for potted plants but is frequently used for treating bad lawns due to mineral imbalance.

Gypsum has calcium in soluble form so adding gypsum is like adding calcium to the ground. After calcium treatment, sodium leaches out of the soil with other soluble salts.


This article covers the entire detail of “What is soft water and how to soften hard water for plants?” We also went through the definition of hard water and its effects on plants.

On that note, let’s conclude the talk here.

From the whole discussion, we know that rainwater is the best option for watering plants. But as rainwater is not available at all times, we prefer soft water instead of hard water because of its low mineral content.

You must use a water softening process if you live in an area with a hard water supply.

While softening hard water, make sure that you use the best method of softening for your plants. Try to use natural methods because these are very effective and safe to use with plants.

Do not use excess soft water or hard water as they both effects plants shortly, but soft water is much more preferable to plants than hard water.

Please do share this article with your friends or family if they also want to know what is soft water and how to soften hard water.


Moiz Atiq.