Garden Basics

Testing Your Garden Soil

Understanding your soils nutrient composition and pH will help you troubleshoot issues at the start and can have a significant impact on the overall health and success of your garden.

Soil can support a large variety and abundance of life. Many organisms live in your garden soil and, the more there are, the more nutrients are available for your plants. These organisms also provide conditions that can suppress pests and diseases.

Follow organic gardening practices to protect the living organisms in the soil.

The soil has an ecosystem all of its own, with bacteria and fungi, as well as insects. Plus a host of others all working together.

There are two main layers of soil, the topsoil and the subsoil. The topsoil contains humus, roots, animals, air, and nutrients. The subsoil is often more dense with fewer nutrients.

Earthworms Are Your Friends


Earthworms are an essential part of healthy soil. There are many different types of worms in the garden soil. Some species create deep burrows, while some others are just under the mulch layer at the surface. Their numbers vary from soil to soil according to the type of soil you have.

  • they ingest large amounts of organic material and excrete them as casts at the soil surface
  • they mix the soil and break up raw plant material
  • their movement through the soil creates passageways and increases aeration and water infiltration.

They thrive in well-aerated but moist conditions and, if you have an abundant earthworm population, these are indications that your soil is of good quality. Use organic fertilizer as some chemical fertilizers can adversely affect earthworms.

Earthworm Abundance Test

Dig out a shovelful of topsoil down to at least 6 inches (15cm) and carefully count the earthworms.

Least desirable - 0
Moderate - 5
Preferred - 10

Knowing The pH Of Garden Soil

pH Scale

Successful gardening requires healthy soil. By knowing the pH of your soil, you can determine the nutrient content and is key to helping your plants give off their best.

The acid-alkaline (sourness-sweetness) balance is known as the pH and is measured on a scale of 1 - 14, with 7 being neutral. Soil with a pH lower than 7.0 is acidic, and soil with a pH higher than 7.0 is alkaline.

The ideal neutral of 7 or close to it will allow essential elements like nitrogen, potassium, phosphorus, iron, and manganese to dissolve quickly, which helps the roots to deliver them efficiently to your plants.

Some plants prefer acidic soil, while others prefer alkaline soil, and the majority of plants prefer an optimum pH range of between 5.5 and 7.0.

Whether the soil is acidic or alkaline, adding lots of organic matter every six months to a year will help greatly. 

How To Correct The pH Of Your Soil

Alkaline Soil

Acid-forming materials can and be applied to the soil, which is too alkaline. A dusting of Flowers of Sulpher or organic material such as oak leaves, pine needles or sawdust will improve the soil.

Some alkaline loving plants are dianthus, salvia, lavender, sages, scabious, thyme, and sweetpea.

Acidic Soil

Use dolomite or lime to "sweeten" acidic soil. Do this in the fall as it takes several months to work.

Some plants that love acidic soil are azaleas, blue hydrangeas, gardenias camellias, magnolia, proteas, ericas, Mackaya Bella (forest bells), yesterday, today and tomorrow and blueberries.

If your soil is exceedingly acidic or alkaline certain nutrients may not be available to the plants and can result in deficiencies;  yellowing leaves are one indication of this.

Types Of Soil

Three main types of soil are:

Sandy Soil

  • nutrient-poor
  • water and nutrients drain through the large sand particles
  • coarse and gritty
  • low water holding capacity
  • poor in nutrients

Loamy Soil

  • contains both clay and sand particles
  • dark brown color
  • moderate water holding capacity
  • rich in plant nutrients

Heavy Clay Soil

  • very dense
  • does not drain well
  • becomes hard and cracks when dry
  • not much life and organic matter
  • plant roots have a hard time growing
  • reddish-brown color
  • very fine particles when dry
  • high water holding capacity

DIY Soil Test

Sandy soil will feel loose, very gritty and rough and is light in color. When rolled into a ball, the particles will not bind together.

Loamy soil will feel crumbly and is dark in color. When rolled into a ball, it will disintegrate.

Clay soil will feel smooth and sticky and is dark grey or red in color. When rolled into a ball, it will retain its shape.

Testing your soil with today's modern soil testers is cost-effective and easy.  Your local extension service will be willing for a small fee to give you a comprehensive report on your soil. 

Using A Soil Test At Home

Buy an inexpensive soil tester which tests for nitrogen, phosphorus, and potash (N, P and K).

You can buy a pH measuring kit or a pH soil probe to do the testing.

  • Nitrogen - gives the plant nutrition and produces leaf growth and green leaves.
  • Phosphorus - perfect for seed development and increases fruit development. It also protects the plants against disease.
  • Potash - strengthens the plant and improves the color.
    The deficiency of potash usually results in a stunted plant with a poorly developed root system.
  • pH - acidity or alkalinity. Choose the plants that will grow well in the pH of your soil or adjust the pH to suit the plants you want to grow.

Testing your soil is quick and easy. In ten minutes, you will have the results for N-P-K tests and one minute for the pH test.

Test your soil periodically throughout the growing season and especially before planting in the Spring or preparing your Fall beds.

USA Extension Office Soil Test

Most counties within the United States have an extension office through their state university.

Because there are so many extension offices throughout each state, they can provide localized information and provide expert advice to residents.

Generally, essential nutrients - like phosphorus, potassium, calcium, and magnesium as well as pH and organic matter, are tested.

In some cases, you may get both soil testing and fertilizing recommendations based on the test results you've sent them.

In cases where the university does not provide soil testing, they may recommend alternative options.

Find your local office here or here.

The key to ensuring that your plants will have a happy life is all about location. By planting in the right environment, your plants will thrive and give you endless happiness.

Testing your garden soil


An understanding of nutrients and the pH together with organic matter makes it so much easier to have a healthy, thriving garden.

Think about "growing" your soil before growing your plants.

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