Soil Testing

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Written by:  Aimee Jarrels, Extension Master Gardener℠ Volunteer of Pender County

A Soil sample box and paperwork beside mums.

Soil Samples And Soil Testing For Gardens

Soil testing may sound like a complicated process with a ton of steps and technicalities to deal with. For most home gardeners, soil testing is the equivalent of laboratories, scientists, test tubes, and chemicals. While they may not be half wrong, soil sampling and testing aren’t that intimidating and are necessary at times to make the most out of your home gardens.

What is Soil Testing and Why Do We Need It?

Soil testing is an easy way to understand the profile of your soil. A detailed testing report will tell you about the soil health, fertility, and productivity as well as the nutrient deficiency, texture, drainage, and quality of the soil. These tests are inexpensive and even free from April-November and are worth the effort when it comes to growing and maintaining a small kitchen or backyard garden for fruits, vegetables, grains, or even ornamental flowers.

Most soils in are relatively fertile provided that the pH levels remain between 6 to 6.5 which is slightly acidic soil. They do not require much addition of nutrients or fertilizers to have good productivity. However, the soil quality and fertility are greatly affected by a change in pH, especially if the level rises (becomes alkaline or basic), waterlogging and poor drainage, soil structure and texture, and the method of gardening. Nutrient leaching and erosion can cause many nutrients to deteriorate like phosphorus and iron, which are essential to the growth of all plants.

Additionally, the toxin levels and incidents of pests and diseases may increase with an increase in pH as well. This in turn will require the application of a greater amount of insecticides, fertilizers, and other inorganic substances which raises the cost.

A soil test provides the means to create a healthy soil climate that will lead to the maximum fertility and productivity of the soil and the maximum potential of plant growth.

Soil Sampling And Testing Process

Soil tests require soil samples. These tests can only give accurate results when the soil sampling is done properly. In fact, chemical tests from inaccurate soil samples can be misleading and cause greater loss. So, the collection of soil from the area or garden to be tested is a prerequisite.

Soil sampling is the process of collecting an accurate representative specimen of the soil to be tested. The selected soil sample should be collected not just from a single spot of the land or any random place. Rather, it should be a mix of the complete soil spread across the area in question. The randomness and uniqueness of the land and soil impact the testing and can give deceptive results.

So, what’s the proper procedure to be followed to collect an accurate soil sample?

  1. Figure out what you want to plant where. Samples must be taken from at least 10 different places.
  2. The soil sample depth is decided by the type of crops. The depth of the sample should roughly be equal to the root zone depth of the crops. Generally, home-grown garden plants will have a root depth of 4-6 inches.
  3. Take all the soil samples with a soil probe or a shovel and mix them in a clean plastic bucket.
  4. Write the information on the outside of the box and on the paperwork. Put the box together and put the soil in it up to the red line.
  5. Do not tape boxes. There is no need to put the soil in a plastic bag first unless you are sending a nematode sample, but that is a different box.
  6. Mail the box, paperwork, and check (if between December and March) to NCDA&CS.

Soil testing is a simple way to improve not just the quality of your soil but also the quality, growth, and productivity of the plants you grow.