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  • Writer's pictureKassi K.

What is Soil Testing and Why is it Important?

Updated: May 16

Soil testing may be considered to be an extra step in gardening and landscaping that is excessive and not always a necessity, and while plants in your gardens and landscapes may not die if a soil test is not conducted, they may suffer unnecessarily. This is because it is impossible to tell what nutrients are in your soil, the acidity of your soil, or other factors that contribute to the health and productivity of your plants just by looking at your soil. Gardening and landscaping is a science, and maintaining soil that is conducive to your plants is the first and most important step to growing a productive garden and keeping the plants in your landscaping healthy and beautiful.

man inspecting the soil

What Is Soil Testing?

Soil testing involves taking a sample of soil and sending it into a lab where that soil sample will be tested to determine the soil pH (how acidic or alkaline the soil is). Soil tests also determine the levels of a number of nutrients that are essential for the healthy growth of your plants such as phosphorus, potassium, calcium, magnesium, sodium, sulfur, manganese, copper, and zinc.

Benefits Of Soil Testing

There are many benefits of testing your soil before planting. Here are a few benefits and a brief description.

pH scale diagram

Aids In Plant Selection

Some plants prefer more acidic or more alkaline soils. A plant requiring acidic soils planted in soil with a high pH will not perform well.

Aids In Soil Preparation

Colorado soil is very rarely ready to be planted in with no preparation or amending due to the clay-heavy nature of Colorado soil. Knowing the exact makeup of your soil will help you know in which way your soil needs to be prepared.

Helps Determine Which Fertilizer to Use

Knowing which essential nutrients your soil has a lot of or is lacking is key to fertilizing your plants properly and effectively. Certain fertilizers are higher in certain nutrients and lower in others, and ideally, a soil test will help you determine which fertilizer to use based on which nutrients are lacking in your soil.

Can Prevent Overfertilization

If your soil is already rich in many nutrients and does not need to be fertilized, a soil test will reveal this. Overfertilizing your plants can lead to damaged roots (excess fertilizer can burn roots) or can stimulate excessive growth, compromising the health of the plant and increasing its susceptibility to disease.

Reduces Pollution

If fertilizers are applied to your soil in excess and therefore not used up by your plants, these fertilizers can runoff into surface waters during storms or leach into the groundwater, causing the pollution of our water supply.

Contributes To Healthier, More Productive Plants

Properly amending and fertilizing your soil help to avoid unnecessary pruning of excessive growth and will overall contribute to healthier, more productive plants.

How To Test Soil

spade digging into garden soil

To test your soil, you will need to collect samples of your soil. Collecting this sample is simple and easy, though it does require more than simply digging up one spot in your yard. Here are step-by-step instructions on how to test soil. If you would like an even more comprehensive guide on how to test your soil, find detailed soil sampling instructions here.

Tools You Will Need

1. A shovel or trowel

2. A clean bucket

3. Plastic bags

4. Permanent marker

Collect Your Soil Sample

You will want to collect "10 to 15 samples from the soil surface (0 inches) to a depth of 6 inches or 8 inches to form a representative composite sample," according to the Colorado State University Department of Soil and Crop Sciences. Take samples from different areas around your yard or the area where you intend to plant and place each sample in your clean bucket. Mix all your samples together thoroughly then add approximately two cups/one pound of the soil into a plastic bag. Label the bag with a permanent marker being sure to include your name, sample depth increment, and location (such as backyard, front yard, garden, etc.).

Fill Out A Submittal Form

Next, you will want to fill out the appropriate submittal form. You can obtain these forms from the CSU County Extension Offices or you can get them online!

Ship Your Sample Off to the Lab

Place your soil sample and submittal form in a sturdy box or envelope and simply mail it to the address in the submittal form.

How To Improve Your Soil

Read And Interpret the Soil Test Results

How to improve your soil will depend on the results of your soil test. Once you receive the results of your test, refer to this document on Interpreting a Soil Test Report. This will help you to understand the results of the test and make decisions on how to move forward based on your planting plans.

Purchase The Appropriate Soil Additives

Based on the outcome of your soil test, you will then want to visit your local garden center to purchase fertilizers, soil amendments, composts, and whatever else you have learned that your soil needs from the soil test results.

Apply Amendments To Your Soil

Once you have acquired the necessary products, follow the application instructions on the packaging or use the soil test results as your guide for application. Once your soil has been amended, it will be ready for planting!

Learn More About How To Test Soil

If you would like to learn more about how to test soil, the benefits of soil testing, how to conduct soil tests, and more, there are tons of resources on Colorado State University's College of Agricultural Sciences website. If you have any specific questions for us, please also feel free to reach out! You can fill out a form or give us a call any time. We look forward to hearing from you!


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