The Importance of Soil Testing, Analysis and How To Do It?

What is the importance of soil testing and how to do it? Soil is the foundation of any successful garden, and understanding its composition is key to nurturing outdoor plants. It is not a necessary practice for everyone but if you’d like to optimise your growing practice, soil testing and analysis could be very insightful and beneficial. Analysis of soil provides valuable insights into soil properties, nutrient levels, pH balance, and other factors essential for optimal plant growth. This information is particularly useful if you’re new to gardening or if you’re planning a new landscaping project.

Understanding soil type will allow you to create an environment where plants can flourish. In this blog post, we will explore the importance of soil testing, the techniques used to test soil, and how to interpret the results to maximize your gardening efforts.

What is Soil Testing and Analysis?

Soil testing is the process of analyzing a soil sample to determine its physical and chemical properties. This information is vital for understanding the soil’s fertility, nutrient content, pH level, and overall health. Upon successful analysis of your soil, you can tailor your gardening practices to provide the necessary conditions for optimised plant growth. 

Common Techniques for Testing Soil

Soil testing can be done using various techniques, most popular ones are DIY home testing kits or professional laboratory analysis. Home testing kits are affordable and provide a basic understanding of soil characteristics, they can be found in most garden centers. They typically measure pH, nutrient levels, and sometimes organic matter content. However, for more accurate and comprehensive results, professional laboratory analysis could be carried out. Laboratories employ advanced techniques to provide detailed reports on soil composition, nutrient content, and other essential parameters. Organisations like the RHS and Yara offer professional soil testing services as well as analysis interpretations and recommendations for treatment.

How Much Does It Cost and When to Test?

The cost of a soil test and analysis will largely depend on which type of test you choose and on the company you are testing with. RHS offer professional test and analysis for around £40. DIY and home testing kits cost anywhere between £8 and £30, again depending on where you buy them from and what you would like to test.

You can carry out a soil test at anytime. However, if the soil has been treated with lime, organic matter or fertiliser the test may be inconclusive or provide inaccurate results.

What Should You Analyse and What to Look for?

Soil testing provides a wealth of insights into the composition and health of your soil. Firstly, it reveals the nutrient levels present in the soil, including essential elements like nitrogen, phosphorus, and potassium. This information is crucial for developing a customized fertilization plan, ensuring that your plants receive the right nutrients in the right amounts.

In addition to nutrient levels, soil testing also determines the soil’s pH balance. pH directly affects nutrient availability, with each plant having specific pH preferences. By understanding your soil’s pH, you can make appropriate adjustments to create an optimal growing environment.

Soil testing also assesses other factors like organic matter content, soil texture, and cation exchange capacity. These details further inform your gardening decisions, such as amending the soil with organic matter or adjusting irrigation practices based on the soil’s water-holding capacity.

Each test should specify it’s purpose. Before testing it’s good practice to know what you’re looking for and why. This will help you avoid any unnecessary testing and help you manage costs. 

Testing Soil pH

It is good to know the pH of your soil before planting or if your plant foliage is starting to yellow and/or if the plant is not growing as expected. Soil pH test indicates whether the soil is acidic or alkaline. pH score of 7.0 is known as neutral. A score below 7.0 means the soil is acidic and a score above 7.0 means the soil is alkaline. You can test your soil pH using combination meters which measure moisture and pH at the same time, pH testing kits or digital pH meters.

pH 3.0 - 5.0
  • Very acidic
  • Nutrients become very difficult to retain in such soil as they become more soluble in acidic conditions. Plant nutrients such as copper, calcium, magnesium and potassium are affected most under acidic conditions.
  • Acidic soils that have a pH below 4.7 often have a low level of nutrients to the bacteria not being able to rot organic matter in these conditions.
  • Solution: Try to raise your soils pH to 5.0. You can do this by adding garden lime to your soil preferably in winter time.
pH 5.1 - 6.0
  • Acidic Soil
  • Ideal for plants such as beech, magnolia, dogwood, camellia and more.
  • Solution: If you would like to grow a variety of plants that aren’t great for acidic soil you could add lime to raise the soils pH.
pH 6.1 - 7.0
  • Fairly acidic soil
  • pH of 6.5 is most ideal for gardeners as most plants will thrive under this pH level, except lime intolerant plants such as Camellias and Rhododendrons.
  • This pH provides optimum environment for nutrients and good bacteria for your plants.
  • Solution: No action required, if plants are showing signs of deterioration or stunted growth it could be a different issue rather than pH levels.
pH 7.1 - 8.0
  • Alkaline soil
  • Reduced risk of clubroot disease
  • Could lead to lime-induced chlorosis due to the insufficiency of iron and manganese
  • Reduced phosphorus availability
  • Solution: Reduce pH if needed using acidifying agents. Look out for sulphur and iron sulphate in the acidifying products. If you have clay soil, you will most likely require a large amount of acidifying agents to reduce the pH level.

Soil Nutrient Analysis

Soil nutrient analysis is a useful indicator of whether your soil is lacking or has an imbalance. This test is recommended if you’re noticing stunted growth, poor flower and fruit production and severe yellowing or browning of your plants. During a soil nutrient test, components such as Potassium, Nitrogen and Phosphorus are usually tested. The following are indications that your plant is lacking nutrients: 

  • Yellowed plants could indicate a deficiency in Nitrogen.
  • Purple, foliage that appears ‘burnt’ or is very dark green could indicate a Phosphorous deficiency.
  • Purple dots on the bottom of the leaf, ‘burnt’ or ‘crispy’ and curled leaves could indicate a Potassium deficiency.

Chemical and Physical Analysis of The Soil

Chemical and physical analysis of the soil is important as it helps to determine your specific soil type, Cation Exchange Capacity and organic matter. Certain plants thrive in clay soil and some completely deteriorate in same conditions. Results from a chemical and physical soil test would help you select plants and trees which would thrive and prosper in your garden.

Biological Analysis of The Soil

Soil obtains it’s nutrition from organic matter and an active population of organisms that live within the soil. Biological analysis of the soil would help you determine the overall health of your soil as well as evaluate the soil’s response to the proposed treatment plan. Biological analysis can even conclude your soils fertility and it’s potential in yielding quality flowers and fruit.


In summary, soil testing is a vital practice for successful gardening. It provides critical insights into soil composition, nutrient levels, pH balance, and other key factors. Armed with this knowledge, you can make informed decisions, optimize plant growth, and create a thriving garden for years to come. There are many ways to test your soil as discussed throughout this article, but after all, our plants are the biggest tellers. 

By incorporating soil testing and plant observation into your gardening routine, you can unlock the secrets of your soil and pave the way for a flourishing garden.