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How to Organically Lower the pH in Water for Plants

How to Organically Lower the pH in Water for Plants

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To the amateur gardener, growing your plants on your property might seem easy. But, what they often overlook is that growing a garden involves far more than simply planting seeds and watering them.

Certain conditions in the soil can have a drastic impact on the way plants grow. One of those conditions is the soil’s acidity and how those plants will react to that level of acidity.

There are ways you can lower the pH level of the water, making it far more suitable for the soil and, therefore, the plants.

Before we get there, we need to learn more about pH and acidity levels and why they play a critical role in the soil we cultivate.

Why is Acidity in Plants?

Testing Soil Acidity

Acidity may sound like a bad thing, but it’s essential for a lot of life across Earth. It determines the quality, characteristics, solubility, and absorbability of things.

Enzymes, which are responsible for just about every biological process in organisms, need acidity to work properly.

Nevertheless, it has to be within the right portion. Otherwise, the smallest fluctuation can be deadly to certain enzymes.

Gardeners often describe acidic soil as sour. Plants living in overly acidic soil likely suffer from mineral deficiencies that adversely affect their growth.

Why is Acidity Important to Plants?

Acidity plays a major role in your plant’s absorption and solubility levels. It also highly influences the breakdown of organic substances, the overall structure of the soil, and the amount of micro life in the ground.

A plant’s pH level can also determine which heavy metals, food elements, pesticides, and other microorganisms growing in that medium end up flushed out of the ground.

Low acidity can mean excess calcium overriding phosphorus absorption. It can lead to pale mottling, chlorosis, and bleaching.

Overall, having a pH level that is too high or too low can be detrimental to your plants.

What Does pH Mean in Agriculture?

Checking Soil Ph

While often heard in a lab, pH is also a widely used term in agriculture. pH stands for pondus Hydrogenii or potential of hydrogen. It indicates a particular solution’s acidity or alkalinity.

These values fall between 0 and 14; a solution valued between 0 and 6.5 is acid, and 7 to 14 is alkaline.

For instance, soda and vinegar have a pH value of less than three. Sap is over an eight on the pH scale. Anything with a value of seven is considered neutral; this can be pure water at room temperature.

Tap water tends to be a little higher in pH because of the extra calcium content, making it slightly alkaline.

Many other things are mildly acidic. Plant substrates, nutrient mediums, and even our skin are all mildly acidic. These have values somewhere between 5 and 6.5 on the pH scale.

When it comes to plants, they veer towards acidic soil requirements.

For this reason, a pH value of 5.5 to 6.5 often occurs in nature. Plant experts consider that to be “neutral” for plants.

How is the pH Determined?

The buffering capacity helps determine the overall pH value of a substrate or a solution. It essentially means that there is a balance present that will continually restore itself.

For instance, let’s assume that you squeezed a drop of acid into a liter of regular tap water (which has a pH of 7). It won’t have much of an impact on the overall acidity of the water.

Meanwhile, if you put that same drop of acid into a liter of demineralized water, the pH level of the water will fall at a substantial level.

It’s because the tap water has bicarbonate in it, while the demineralized water does not. Bicarbonate is a key ingredient when buffering substances for pH values between 5.5 and 7.5. It binds itself to acid in a particular solution and releases carbon dioxide into the atmosphere.

This is the process of neutralizing the acid. Changes in the overall acidity will be minor so long as there is bicarbonate present.

Why Your Soil Has Low Buffering Capacity

Testing Soil Sample

If you see a 5.3 p.H value, it indicates that all the bicarbonate has been used up. It also means that the solution no longer has buffers to it.

That makes this pH unstable to the point that it’ll change immediately if any acid is added to it. Consequently, you can find the required acid content of your soil from the amount of bicarbonate present.

You can get the bicarbonate content level of your tap water from your water company in a measurement of milligrams per liter.

Other Factors and Their Impact on Buffering Capacity

The composition and freshness of the substrate are crucial factors in its acidity and buffering capacity. The presence of calcium, organic material, and bicarbonate can alter the overall pH level.

For instance, clay contains calcium carbonate, giving it a high pH value. It makes it more difficult to change, as opposed to acidic substances like sandy soil and peat soil.

Besides these compounds, the acidity in the soil can be greatly influenced by the plant itself. Some roots will secrete alkaline or acidic substances.

It primarily depends on the stage of development of the crop, the differences in root temperature, the food available, and the light intensity. All of these factors indicate that the plant’s pH can fluctuate constantly.

The goal is to keep the root environment at an acceptable limit as far as the pH level goes. Doing this will keep your plants growing healthy and strong.

How to Test Your Soil’s pH Level

You can measure your soil’s pH using a pH testing kit or with a few kitchen supplies. Here’s how to get started using the latter:

Get a Clean Soil Sample

Using your shovel, dig up around four to six inches into your soil. Grab a fistful of the dirt with a hand towel. Next, take out any sticks, clumps, or stones from your soil sample.

1. Add Water

After cleaning the soil, place it in a bowl and pour distilled water on it. The mixture should turn to mud.

2. Pour Vinegar

Empty about half a cup of vinegar into the muddy mixture. Make sure it’s well-incorporated. Now comes the testing part.

If you notice signs of fizz or bubbles, your soil is likely alkaline. If the reaction didn’t happen, move on to the next step.

3. Add Baking Soda

Get another clean soil sample and pour water over it until it turns into mud. Then, sprinkle and mix in half a cup of baking soda.

Observe the solution for any reaction. If it becomes fizzy, the soil is likely acidic.

4 Methods to Organically Lower the pH in Water for Plants

Fortunately, you can implement multiple methods to organically lower your plant’s pH. From adding sulfur compounds to using rainwater, these components will increase your plant’s acidity.

Peat Moss

Peat moss rates slightly acidic on the pH scale. The organic matter has a pH of around 6.0. Aside from that, it’s also excellent at water retention.

You can integrate it into your plant’s water by shoveling it into a nylon stocking. Next, submerge it in your water jug for a few hours, or for stronger results, overnight.


Rainwater is naturally acidic because of its excessive exposure to carbon dioxide in its surrounding atmosphere.

Subsequently, if you live in a region prone to heavy rainfall, collect a few cups and mix them with your plant’s water.


Mixing sulfur and water creates sulfuric acid, an ideal pH-lowering compound. You can get your hands on sulfur from a gardening store selling it in pellet or powder form.

Commercial Organic Acids

If you’re looking for the easiest route, we recommend purchasing a commercial packet of organic acids. They can come in various forms, such as acetic, phosphoric, or citric acids.

These products are notoriously potent. For this reason, you want to use a careful hand when adding them to your plant’s water. Be sure to also put on protective gear when handling the acidic powder since it can irritate your skin.

Changing the Water to Keep the pH Balanced for Your Plants

Pouring Liquid Fertilizer

Some additives can make the water you use on your plants more acidic or alkaline in nature. Generally speaking, plants will thrive with a pH of 5.5 to 6.5.

Anything below 5.5 puts your soil under the acidic category, while anything above is alkaline. If the pH of the water you’re using is off somewhere, there are ways to fix the problem. That way, your plants can grow at an improved rate. Here’s how you can maintain that pH balance.

1. Add Fertilizers

The first step is to add any fertilizers or nutrients. If you’re growing your plants hydroponically, wait about an hour before moving on to the next step. For those growing in soil, 24 hours will do.

2. Test Soil

The next step is to test the growing medium. You can do this by taking a pH test, using a test strip or an electronic test kit, and following the instructions that come with it.

When you get the reading, compare it to the ideal pH type for the specific plant you’re growing. It’ll determine if you need to lower or raise the pH of the soil.

3. Fill a Jug with Water

Filling A Water Jug

Get a gallon jug and fill it with clean water. Depending on the type of substance you’re using to make the pH adjustment, water requirements may differ.

You can then proceed with either route:

If pH Is Low

To raise your pH level, you need to add components like wood ash, lime, or a specifically formulated solution.

If pH Is High

If you want to lower the pH, you will need phosphoric acid, sulfur, or a pH-lowering solution. The directions might call for a solid material or materials to add to a liquid solution.

In this case, you need to give those materials time to soak in the water. Usually, a few hours is enough to allow it to steep, making it ready for mixing.

4. Add the Solution to Your Soil

After your concoction has been mixed, it’s time to water your plants with that solution. If your plants are growing in a solid like perlite, make sure to water the plants the same way you would water your plants with regular water.

On the other hand, If you’re growing your plants hydroponically, you’ll want to add your pH solution to your hydroponic solution.

5. Re-Test Soil

After you watered your plants, you’ll want to retest the soil’s pH levels. It’s to determine whether another treatment is necessary. For hydroponics, this means waiting about a half hour to test the pH again.

If you’re growing in soil or another type of solid, you’ll have to wait 24 hours before testing the pH level again.

How to Know If the pH Is Too Low

Several factors can help you determine whether the pH level in your soil is on the acidic end.

Nutrients Dissolve Too Quickly

Excessive dissolving causes an excess of aluminum, iron, and manganese. With excessive rinsing comes potassium, phosphorus, molybdenum, and magnesium deficiencies.

Poor Soil Condition

If your soil seems like it is generally poor or inhibited, that is likely a sign that it’s too acidic for the general health of your plants.

You’ll notice signs like wilting grass blades, yellow spots, and excessive weed growth.

Environmental Factors

Environmental factors like heavy rainfall and dry spells can heavily impact your soil’s pH. Rain and droughts increase acidity.

Rainfall, in particular, triggers a leaching process, where the excess water rinses the soil of its calcium and magnesium, making way for excessive aluminum and iron compounds. 

Subsequently, the overly acidic elements can stunt your plant’s growth.

How to Know If the pH Is Too High

Having a pH level that’s much too high can be just as dangerous for your plants, stifling their ability to grow properly. Like a pH level that is too low, some signs can indicate that your pH level is too high.

Reduced Nutrient Absorption

If the nutrients you add face difficulties with dissolving, this can lead to iron, calcium, and phosphate compounds precipitating.

You may also see a decrease in absorption for compounds like phosphate, iron, and manganese in particular. That reduced absorption rate can also apply to other elements like boron, copper, and zinc.

Poor Appearance

With nutrient deficiencies, your overly alkaline plant can exhibit signs like:

  • Interveinal Leaf Chlorosis: It comes from an iron deficiency and results in a yellow tint on the region surrounding the leaves’ green veins.
  • Leaf Necrosis: Due to poor soil and abiotic stress, your leaves’ tips will appear brown.
  • Brown Spotting: High soil pH can increase molybdenum production. Too much of the compound can become poisonous and turn your leaves brown.

Final Thoughts

How can you organically lower the pH in water for plants? Well, you can incorporate various techniques to balance your plant’s pH.

Some of them include adding rainwater, peat moss, or sulfur. At the same time, you want to ensure that you’ve added the right amounts by testing your pH level consistently to avoid overly decreasing your pH.

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Sunday 22nd of May 2022

Check out the snippet on Wikipedia about the origin of pH meaning, search the page for "pondus Hydrogenii".

Nice site! <3