Is Alkaline Water Good for Plants? A Green Thumb’s Answer

Last updated Nov 29, 2021

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If you own an alkaline water machine or another alkaline water filter, you’re probably wondering if it’s okay to water your houseplants or garden with alkaline water.

Since I’m a green thumb and full of alkaline water knowledge, I’m the guy to ask. I’ll tell you upfront that this isn’t a yes-no question. There are variables in play that lead to several different answers.

By the end of my guide, you’ll know for sure if alkaline water is good for your plants. From experience, I know how important soil pH is.

If the soil pH goes outside the range your plants prefer, you’ll run into nutrient lockout and eventually, dead plants.

But don’t worry, we’re not going to let you kill any of your beautiful plants because I know how heartbreaking it can be.

First, let’s start with the answer to the question.

Is alkaline water good for plants?

The answer is yes and no.

It all depends on the type of plant.

Some plants prefer alkaline “sweet” soil while others prefer acidic “sour” soil.

Most of the plants I’ve grown prefer a slightly acidic pH. I typically water my plants with water that has a pH of between 6 and 6.8.

Does this mean you can’t water your plants with alkaline water? Not necessarily.

The best way to use alkaline water is to adjust the pH of your water with acidic pH drops and measure the pH of the water with a reliable digital pH meter or pH test strips (I prefer a meter).

Once you’ve adjusted the pH of your water and confirmed that it’s in the proper range for your plant, you can go ahead and water your plant.

However, if you’re growing in organic soil or properly mixed conventional soil, the soil has a way of taking care of the pH for you.

As long as you’re not consistently watering your plants with water above pH 8 or 9, the soil will buffer the pH of your water.

Tip: The pH of your soil is more important than the pH of your water. If something in your soil is throwing off the pH or burning the plant’s roots, you’ll cause a lot more damage than watering your plant with water that’s above the optimal pH ever will.

What’s great about alkaline water from a water ionizer is it’s been filtered to remove water contaminants to undetectable levels, and all types of plants can appreciate this.

Now that you have a basic understanding of alkaline water’s effect on plants and soil, let’s check out which plants like alkaline water.

Plants That Like Alkaline Soil

There’s a long list of plants in several categories that like alkaline “sweet” soil. Let’s check out a handful of varieties in each category:


  • Lavender
  • Goldenrod
  • Foxglove
  • Daylilies
  • Salvias


  • Gingko Biloba
  • Ornamental Cherry
  • European Ash
  • Horse Chestnut


  • Virginia creeper
  • Boston ivy
  • Winter Jasmine


  • Lilac bushes
  • False Cypress
  • Yew bushes
  • Rose of Sharon bushes
  • Viburnum

While the plants above don’t mind alkaline soil or water, I want everyone to remember that your soil pH is A LOT more important than your water pH.

You can still water plants that prefer acidic soil with alkaline water as long as your soil pH is in check, and you don’t go overboard with your alkaline water pH level.

This leads us to the next section…

How to Test the pH of Your Soil the Easy Way

In this section, I’ll share a simple method that anyone can do to test the soil pH.

Water your plants and measure the pH of the water that comes out of the bottom holes in your pot or container. This will give you a better understanding of your soil pH.

If you’re watering a garden instead of a potted plant, punch several holes in the bottom of a plastic cup or use a small pot to scoop out a test sample.

I use pH test drops with a little capped test tube to hold the water sample. I also always keep a turkey baster or glass water dropper nearby to collect the sample.

As long as the water coming out of the holes (the runoff) shows a pH reading in the optimal range for your plant, you’re all set.

It’s always best to research your plant to identify the correct soil pH and the type of soil your plant prefers.

For example, you water your plant with water that has a pH of 8.5 and your runoff has a reading of 6.5. If your plant likes slightly acidic soil, you have nothing to worry about.

If you water your plant with pH 8.5 and the runoff is 8.5, then you have a problem. Sometimes growers will try to correct a soil pH problem by watering with low acidic or high alkaline water, but this is only a temporary fix.

Getting your soil pH right is much more important than the pH of your water.

The reason I like to water plants that prefer slightly acidic soil with slightly acidic water is that I like to play it extra safe and make my plants’ lives as easy and comfortable as possible.

One of the reasons I’m so fascinated with the health benefits of alkaline water in humans is that my botanical background taught me how important pH is for plants. In my opinion, it’s just as important for humans.

A second option: You can also use a soil pH meter to test the pH of your soil. However, I prefer the runoff method because it’s always given me more accurate results.

How to Use a Water Ionizer to Water Your Plants

The wonderful part about owning a water ionizer is its ability to make water with different pH levels.

For example, the Tyent UCE-11 and ACE-11 ionizers have the ability to make water between pH 1.7 to 12.0.

They also give you the option to create your own presets for any pH level you desire within that range. Awesome, right?

No matter what plants you want to water – alkaline or acidic soil-loving plants – a Tyent ionizer can get your water pH right where you want it.

Since I’m an organic gardener, I love this feature because one of my gripes with pH adjuster drops is they’re not usually organic. Although, the difference is minuscule. I’m just obsessed.

With the Tyent, you can make any level of pH 100% organically since the ionization process is all-natural and adds nothing to your water.

Another advantage is a Tyent ionizer won’t raise your TDS (total dissolved solids) to an undesirable level since it uses the minerals that are already in your water.

Tyent ionizer filters are incredibly powerful and remove water contaminants to undetectable levels. The same micron rating of .01 is used in kidney dialysis machines.

Plus, there’s a setting on the machine for neutral pH purified water, which is also great for watering plants.

Alkaline Water & Plants Precautions

If you use an alkaline water filter pitcher to water your plants, you want to be more cautious than if you’re using an ionizer.

Since alkaline water filters use minerals to ionize your water and raise the pH, the TDS reading could easily become too high.

Plants don’t want to be overloaded with minerals they don’t need or can’t absorb.

Everything your plants need should be in your soil. Sometimes I like to challenge myself as an organic gardener to see if my plants can live off what’s in the soil alone without experiencing any nutrient deficiencies.

Getting back to the point, you’ll want to test the TDS of your water if you use alkaline water from a pitcher to water your plants.

Once your TDS reading gets above 400 or even 1000, this is too high for most plants.

I like to keep my TDS low when I water my plants. The only time my TDS gets high is when I water with my compost tea.

If you have hard water, it’s better to start with a pre-filtration system before running your water through an alkaline pitcher filter.

Even then, I’m not fond of the idea because I like to be in total control of what’s in my plants’ water. I’m not 100% sure if these pitchers release minerals all my plants will enjoy.

Do you see the difference between using alkaline water from an ionizer and pitcher filter now?

To summarize: water ionizers don’t add minerals to your water. They use the minerals that are already in your water to make alkaline ionized water, acidic water, and neutral pH purified water. Alkaline water filter pitchers mostly use basic filtration and add minerals to your water.

How to Adjust pH in Soil

There are several ingredients you should be able to pick up locally or order online to keep your soil pH in check.

The best way to raise the pH of acidic soil is with organic dolomite lime. Follow the instructions on the bag to ensure you don’t go overboard because a little goes a long way.

Dolomite lime mostly consists of calcium and magnesium.

A good way to buffer your soil from the get-go is by adding gypsum when you mix it.

Gypsum does a great job of buffering your soil pH and allows you to water your plants with water that’s a bit outside the optimal pH range.

Gypsum powder is great for mixing with water to correct a pH problem, while pelletized gypsum is better for mixing into your soil for a more sustained release.

If you need to raise the pH in your soil fast, hydrated lime is the most powerful option. However, I only recommend using this if you’re an experienced gardener because a pH shift can easily shock and kill a lot of plants.

It’s better to stick with gypsum and/or dolomite lime and start with a correct pH.

A good way to make soil slightly acidic for acid-loving plants is with the addition of ammonium sulfate, which is rich in nitrogen. Nitrogen gives your plants their lush green color.

Follow the instructions on the package and be sure to test your soil pH before you plant.

Tip: You may want to let your soil “cook” or sit for a few weeks after you mix it. Mix it, then moisten it (not too much), then let all the ingredients cook together. After a few weeks, measure the pH to assure it’s in the correct range.

If you don’t want to mix your own soil, be sure to buy the correct pre-mixed soil for your plants at the nursery or garden supply shop.

Most pre-mixed soils already have the right amounts of the ingredients I listed above in them.

I prefer to mix my own soil because it’s fun. I like to add my own special ingredients and use compost tea to get the beneficial goodies flowing through my soil mix.

Final Thoughts

Is alkaline water good for plants? Now you know the answer to this question. I warned you it was more complex than a simple yes or no.

If you made it this far, let’s go back over the key takeaways since there’s a lot of info to take in here:

  • The pH of your soil is more important than the pH of your water.
  • Test your soil runoff using the method I explained above to ensure your soil is within the ideal pH range for your plant.
  • A water ionizer is better than an alkaline water filter because ionizers don’t add minerals to your water that can spike your TDS.
  • A top water ionizer gives you the ability to choose your exact pH. You can make acidic water, alkaline ionized water, or neutral pH purified water for your plants with an ionizer.
  • Take advantage of soil buffering ingredients such as gypsum to make your soil more forgiving of water that’s outside the ideal pH range.
  • Don’t use water with a high pH (above 8.5 max) for any plants. There’s no reason to use water with a high pH. It won’t benefit your plants. What’s in your soil is more important.
  • Plants love purified water that still has a small number of minerals in it, just like humans. That’s why I love the idea of a water ionizer that uses powerful filters to remove water contaminants for watering my plants.
  • Last, if you use an alkaline water filter pitcher to water your plants, be sure to check the TDS because it could be too high.

Do you feel like a soil expert yet? Next time you talk to someone about soil, I bet you’ll sound like one.