How to Test and Adjust Soil pH? – The DIY Guide

If you are planning to raise a garden then it’s important that you know the pH level of the soil. A working knowledge of the pH level of your garden soil will allow you choose the right plants, because plants require different levels of alkalinity to thrive. Once you know the soil pH, you can adjust it accordingly to suit your needs. There are a number of ways to test and adjust the pH of your soil – let’s go over a few of them:

Testing Soil pH

1. By using a Commercial Test Probe

  • To use a commercial test probe, dig a hole about 4 inches deep in the ground. Then remove foreign wigs and debris from the hole.
  • Next, fill the hole with clean clear water. Be sure to use distilled water and not tap or spring water. Your local pharmaceutical store should have lots of distilled water for sale. Distilled water is better than other sources of water because of it’s neutral pH.
  • Next, insert the commercial pH testing probe into the muddy-like water in the hole. Be sure that the test probe is clean and free from contaminants.
  • Take the test probe for reading. Allow the probe to sit in the muddy water for about a minute before taking it for pH reading. A pH value above 7 indicates an alkaline soil while a pH value under 7 indicates acidic soil.
  • Accurate reading is all about empirical analysis from different spots. Repeat procedure I –IV on several spots within the garden then take the average reading as the pH value of your garden soil.

2. By Using Paper Test Strips

pH reading using paper test strips is one of the oldest and most common ways of testing the pH of garden soil. Its popularity stems from the ease of using strips. Follow the outlined procedure below:

  • Purchase the test strips also known as litmus paper from any local pharmacy or laboratory. Litmus paper is cheap and harmless. You can get them for free if you know one or two persons working in a laboratory. If you can’t find one in your locality, purchase them online.
  • Take soil samples from different places in the garden and mix them up with distilled water from your local pharmacy. Mix the soil sample in a bowl until you get milk like texture.
  • Test the pH by dipping the litmus paper in the mixture for about 20 seconds. Hold the non-reading end and dip the reading end in the mixture before dipping into distilled water to clean off the dirt.
  • Compare your results with the key included in your pH test kit. Litmus paper test is color-coded so be careful when you are matching the results. Select the color that most suitably resembles the one from the litmus paper. You should see a corresponding pH to this color.

Adjusting Your Soil’s pH level

We’d like to emphasize that the right soil pH is important for the health of your plants.  Optimum pH can dramatically improve the plant's ability to absorb nutrients. The first step to adjusting your garden soil’s pH is knowing what changes to make – either to increase acidity/lower the pH or increase alkalinity/increase the pH. To do this, there are a number of compounds you can add to make lasting changes and improvements.

By now, you should know your soil type. The type of soil you have can determine the kind of changes you employ to adjust the pH.  A well-drained soil can be altered easily than compacted soils with lots of clay.

pH is defined as the level of acidity or alkalinity of the soil. A pH of 7 indicates neutrality while pH reading below 7 indicates acidity. Any reading above 7 is alkaline. For most plants and micro-organisms a pH between 6 to 7.30 is the most ideal condition. However, the type of plant you intend to grow will determine the right soil pH for it. If you are confused about this, do a little research online to find the various pH levels for garden plants.

How to increase soil pH?

Increasing soil PH improves the alkalinity of the soil.  To do this, follow one of the methods below:

Adding a liming material

If you have tested your soil and found it to be too acidic, and a liming material to reduce the acidity or increase the alkalinity of the soil. Using compounds made from limestone or limes are the best way to reduce the acidity of the soil.  Pay a visit to a local garden shop to buy these compounds. Lime comes in four variants that can be used depending on the amount of moisture in the soil:

Pulverized: Pulverized lime compounds are easier to absorb by the soil because of their finely grounded nature. However, they are harder to apply because they often clog the applicator.

Pelletized or granular lime compounds are easier to spread around the soil but not readily absorbed by the soil.

Only use hydrated lime compounds in highly acidic soils because they are a more water-soluble alternative to others.

Lastly, there are lime compounds that contain some micro-nutrients like dolomite. Dolomite is a source rich in calcium and magnesium so they ought to be used in soils deficient of these nutrients.

Using wood ashes

An inexpensive way of increasing the alkalinity of your soil is by using the ashes of burnt wood.  Ashes of burnt wood not only reduce acidity but it’s also a source of calcium, boron, phosphate and potassium.  Applying wood ash is not an immediate solution to the acidity of your soil rather it’s a gradual approach to reducing the acidity of your soil over time.  Here are two pro tips for applying wood ash:

  • Keep the wood ash from coming in direct contact with plant rooting system and germinating seeds.
  • Sandy soil is the best soil type for wood ash.

Applying the lime source

 Follow these useful tips to apply the lime source for optimum results:

  • Till the liming source two to three months before the planting season begins to allow much time for the PH to adjust.
  • Use your bare hands if you have a small garden or make use of a spreader in a large garden.
  • To work the lime effectively into the soil, make use of a rake. Lime isn’t water-soluble so working it into the soil will improve absorption.

Decreasing soil PH or increasing acidity

To decrease soil PH or increase acidity follows one of the procedures below:

Make use of organic materials/matter

Over time organic matter such as compost or manure can slowly lower soil’s pH. Be warned though, that changing soil pH with organic matter can take years – only use this technique if you have long term gardening goals.

Consider sulfur application

Adding sulfur is another way to increase the acidity of soil by lowering the pH. Applying sulfur depends on some environmental factors like temperature, bacteria, and moisture. The unpredictability of these environmental conditions means it can take up to 8 months before notable changes occur. Here are some pro tips to sulfur application:

  • Avoid the use of finely ground sulfur because it’s too fine for soil acidifying.
  • The biological reaction of Sulphur and bacteria is the underlying reason behind the increase in acidity.

Try adding Aluminum Sulfate

The chemical reaction involving aluminum instantly makes the soil more acidic. Because of the instantaneous results, many gardeners prefer to use aluminum sulfate to organic matter. However, despite the positives it’s very easy to outshot soil requirements and potentially harms the plant.

You will still have to till the sulfur, organic matter and aluminum sulfate into the soil for best results. Remember to apply organic matter multiple times if you want to see substantial results.

Brice The Botanist
 

Growing up in Ventura, California famous for it's rich gardens. Brice has spent most of his life trying to help make the world greener. Studying Botany at CSRA, he's made it a lifelong passion to greenify every home.

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