March 9, 2022

How to Test your Garden Soil: A Comprehensive Guide

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If you want to have a successful vegetable garden, healthy soil is an important aspect of your work and a soil test should be one of your first steps. Soil health is crucial for growing healthy plants because the quality of your soil affects the availability of nutrients, water retention, and drainage. Without knowing what type of soil you have, it can be difficult to amend it in order to get the results you want. In this comprehensive guide, we will discuss all aspects of soil testing so that you can get the information you need to improve your garden.

Why test your garden soil? What will a soil test tell you?

The first reason to test is to determine the nutrient profile of your soil. You’ll learn which nutrients are present or lacking, in what quantities. This will tell you what you might need to do to amend your soil for overall plant health.

Secondly, a soil test will reveal the pH of your soil. The pH is a measure of how acidic or basic (alkaline) your soil is. Different plants have different preferences for pH, so this information is crucial in order to choose the right plants for your garden and/or amend the soil appropriately.

Finally, you will be able to determine the soil texture. Soil texture is a measure of how much sand, silt, and clay are in your soil. This information is important because it will help you to think about the physical characteristics of your soil and how they will impact your plants (think about root spread, drainage, and compaction). You can amend your soil to be more plant-friendly once you know what it needs.

How do you test your garden soil? Multiple Options…

There are a few different ways to test your soil, and you may want to use a combination of methods to get a true understanding of what you are working with.

Option 1: Using a Soil Test Kit

One option is to purchase a soil test kit from your local garden center or hardware store. You can also often request these kits from a local University Extension Office at a discounted cost or for free. These kits generally contain a collection of tests that will give you the information mentioned above – nutrient quantities, acidity, etc. They work by adding a small amount of soil to a provided container, then adding water and chemicals that will change color to indicate the presence of different nutrients. The included guide will help you interpret these results.

A soil test kit is the best means for understanding the nutrient composition of your soil, whereas many tests can be used to learn more about the density and physical characteristics of your garden soil.

The University of Vermont Agricultural & Environmental Testing Lab is an example of a service that provides professional soil testing.

testing soil drainage with water in a hole

Option 2: Testing Soil Without a Test Kit

If you don’t want to purchase a test kit, or if you want to know more than the test tells you, there are several tests you can do at home to get a general idea of your soil’s condition.

Testing by Observation

One simple “test” is to simply look at the color of your soil. Healthy soil will be dark brown or black and have an earthy smell. Soil that is sandy will be light-colored, while clay soil will be heavy and dense.

You can also do a soil test observation in a jar. For this test, you will need a quart-sized Mason jar, some soil, and water. Fill the jar with soil to within an inch of the top, then add water until it is just below the top of the soil. Stir well and let sit for 24 hours. The next day, look at how much sediment has settled on the bottom of the jar.

If most of the soil is still suspended in the water, your soil has a high sand content. If it takes longer than a day for the sediment to settle, you have clay soil. If the sediment settles within an hour or so and there is still some water above the sediment, your soil has a good mixture of sand, silt, and clay.

Testing by Feel

Another way to test your soil is to feel it between your fingers. Try this with a handful of soil from different parts of your garden. Soil that is rich in organic matter will be soft and spongy, while soil that has been depleted will be hard and crumbly.

A ribbon test is another texture-based test you can do with your fingers. Take a small handful of soil and add enough water so that it forms a ball in your hand. Then, try to make a ribbon out of the ball. If it breaks easily, your soil is sandy. If it’s hard to form a ribbon or if the ribbon is crumbly, your soil contains clay. If the ball forms a ribbon but doesn’t break easily, you have loamy soil, which is ideal for gardening.

Testing by Smell

One of the most telltale signs of a soil issue is its smell. If your soil smells sour, it may have an acidic pH that is not suitable for plants. A sweet smell could indicate that there are high levels of nitrogen in the soil, which can be harmful to plants if present in large quantities.

Testing the Ph of your Soil with Vinegar

Another way to test the pH of your soil is with vinegar. Add one tablespoon of white distilled vinegar to a quart of water and mix well. Take a sample of soil from your garden and add it to the mixture. If the soil fizzes, it has a high acidity and may not be suitable for all gardening (but it might be great for things like blueberries!). If the soil doesn’t fizz, it has a low acidity and is more suitable for gardening.

Percolation Test

A percolation test is a test that will show you how well your soil drains. This is an important factor to consider when gardening, as plants need access to both water and air. To do this test, dig a hole that is 12 inches deep and at least 18 inches wide. Fill the hole with water and let it drain for 30 minutes. Then, fill the hole with water again and let it drain for another 30 minutes.

After the second draining, measure the depth of the water in the hole. If the water has drained more than six inches in two hours, your soil drains well. If it has drained less than three inches, your soil doesn’t drain well and you may need to improve it before gardening.

Soil Compaction Test

One final test you can do at home is a soil compaction test. This is especially important if you plan on growing vegetables, as compacted soil can make it difficult for roots to grow. To do this test, take a screwdriver or other sharp object and push it into the ground. If it is difficult to push in more than six inches, your soil is compacted. You can improve the soil by adding organic matter such as compost or mulch.

Once you have the results of your soil testing, you can search for more information on amendments that will help you to address each component of your soil health (click here for information on increasing nitrogen levels, for example). Knowing what to look for is an important first step!

No matter which method you choose, taking the time to test your garden soil will help you make informed decisions about how to improve its health and support healthy plant growth. By understanding what’s in your soil and how it reacts to different conditions, you can create a thriving garden that is better able to withstand pests, diseases, and extreme weather.

Now that you know how to test your garden soil, are you ready to get started? Share your results in the comments below and let us know how your garden grows!

Happy gardening!