woman with watering can in a greenhouse lowering soil ph with vinegar solution

How To Lower pH In Soil With Vinegar

Soil pH affects plants’ ability to grow by making certain nutrients available or unavailable. This makes it in the best interest of gardeners to test their soil pH and modify it if necessary. If you’re curious about how to lower the pH of the soil with vinegar, read along to learn why you might want to do this and how. You just might uncover the reason why your garden hasn’t been thriving.

Changing your soil’s pH is a continual effort that requires time, patience, and specialized amendments. If you want to acidify your soil, you can pull it off using household vinegar that you might already have in your kitchen.

Why would I need to lower the pH in my soil?

The soil’s pH affects the ability of the plants in the soil to uptake certain nutrients. In general, plants enjoy a neutral pH of around 7 but certain plants have evolved to thrive in more extreme soils.

So essentially you have two reasons why you would want to lower the pH in your soil. The first is because the soil is too alkaline and it is negatively affecting your plant growth. When soil is too alkaline (high pH) certain essential minerals like iron and manganese aren’t available to the plant. You would then lower the pH of your soil to bring it towards a neutral pH.

The second reason you might need to lower the pH in the soil is that you want to grow specific plants that call for slightly acidic soil. If you want to make a special garden bed to grow roses and raspberries, lower your soil’s pH to make it slightly acidic.

How do I know what pH my soil is

There are several ways to know what pH your soil is depending on what you have on hand and how precise you need to be.

The most exact reading will come from a soil pH meter. It kind of looks like a thermometer. But don’t get confused, instead of telling you the temperature, it will give you the pH including the decimal. For example, it’ll be able to differentiate between a pH of 5.4 and 5.5.

You could also use litmus paper to test the pH rounded to the nearest whole number, but I wouldn’t recommend it. Amending your soil pH will require precise readings so you can make an informed decision on how much solution to apply.  A difference of a few decimal points will make a huge difference in the growth of your plants.

Purchase these pH test kits from any garden centre or most hardware stores. They aren’t too expensive and are well worth the investment if you plan on checking the soil pH periodically.

Is a lower pH more acidic

The pH scale ranges from 0 to 14 and measures how acidic or basic a solution is. It might be a bit counterintuitive, but lower pH is more acidic while a higher pH is more basic, or alkaline.

A neutral pH is 7, which means that everything below that (starting at 6.9) is acidic and everything that reads 7.1 or above is alkaline. How far away the number goes from 7 affects the degree of acidity or basicness. For example, a solution with a pH of 6.8 is slightly acidic while a solution of 3 or 4 is extremely acidic.

How to lower pH in soil with vinegar

You can lower your soil’s pH by diluting vinegar in water and using the solution to water around your plants.  Remember that it’s better to under-apply the amendment than to overdo it. Soils that have a pH below 6.0 become much too acidic for anything (including roses and raspberries) to grow.

First, you need to measure the pH of your soil by taking samples from around your growing area to find an average. You can use litmus paper or a test kit like we reviewed above. This reading will give you an idea of the ‘base’ pH of your soil and how much you need to modify it.

What type of vinegar to use

Then you need to decide whether you’ll be using household vinegar (which has a 5% concentration of acetic acid) or agricultural vinegar (20% acetic acid). This means you’ll need much more household vinegar than agricultural vinegar, but you won’t run the risk of over-acidifying your soil.

household vinegar sitting on a table
Household vinegar is usually 5% concentration.

Once you’ve got your vinegar on hand, dilute about 5 tablespoons of vinegar in plain tap water. Depending on where you like, the tap water might be alkaline and will affect the pH reading. Keep adding a bit of vinegar until the water has a pH of about 2.7.

Apply diluted vinegar solution

Use your diluted vinegar solution in a watering can or inject it into your irrigation system, then water your plants normally with this water. Depending on your garden’s size, you’ll need to calculate the amount of vinegar solution needed to water the soil.

Check soil pH periodically

Once every three to four weeks, check the pH of your soil and repeat the vinegar solution application if necessary. This treatment is only temporary and will need to be repeated periodically to keep the soil acidic. Based on the pH reading, determine how acidic the vinegar solution should be.

When applying the diluted vinegar solution, take caution not to water the plants directly or apply it to recently transplanted plants. Weak root systems will be far more sensitive to acidity.

What pH should I aim for

Your target pH depends entirely on what you want to grow, but in general, it should be neutral. When soils get overly alkaline or acidic, essential nutrients like nitrogen and iron aren’t available to plants anymore. Although they are present in the soil, the plants can’t uptake them and will quickly die.

Some plants, however, actually enjoy acidic soils and would benefit from a soil pH of 4.5 to 6.5. Blueberries and roses, for example, actually do better in acidic soil but at different intensities. While roses benefit from slightly acidic soil of about 6 to 6.5 blueberries will enjoy a pH between 4.5 and 5.5.

How often should I check my soils pH

Amending the pH of your soil isn’t an exact science. You can’t just apply a pH modifier and expect it to work overnight and stay stable. If you just want to monitor your soil’s pH, test it every month to understand how fertilizing and water cycled affect your soil’s pH.

If you are in the process of changing your pH, test the soil every few weeks to monitor the progress. Also, make sure to test right before you apply more amendments so you know the soil’s baseline.


Lowering the pH of your soil with vinegar is a great way to get introduced to soil pH. Unlike other pH amendments, vinegar is completely safe for humans, is easily available in any supermarket, and it’s much harder to over-apply.

If you’re hoping to make your soil slightly acidic or make an alkaline soil more neutral, try using vinegar instead of heavier amendments. You’ll get the feel for testing your soil’s pH and can turn the whole science project to do with the kids.