How to Test and Improve Your Soil
BY ALISON HOOVER | MARCH 11TH, 2023 | BLOG, LANDSCAPING
A great-looking lawn begins with great soil. Testing the acidity and composition of your soil is an easy process. Let’s break down why and how to test and improve your soil, as well as the soil amendments you’ll want to consider.
In this article, we’ll cover:
- Why You Need to Test and Improve Your Soil
- Where to Get Soil Test Kits
- How to Test Your Soil
- What Are Soil Amendments?
- Best Soil Amendments
- Types of Soil
- How to Improve Your Soil
- FAQ About Testing Your Soil
Why You Need to Test and Improve Your Soil
Plant growth is impacted by the pH balance of the soil. Grass and plants can’t survive in soil that’s too acidic or has too much alkaline. The pH number ranges from 1 to 14. A level below 7 is considered acidic, and above 7 is alkaline. A measurement of 7 is neutral.
Knowing the pH of soil lets you decide what to plant and where. The results of a soil test will also indicate how you can improve plant quality. This includes adding fertilizers and other amendments.
Where to Get Soil Test Kits
You can buy a soil test kit at any home improvement or lawn and garden store. Choose a kit based on what you want to learn about your soil. These kits will come with detailed instructions from the manufacturer.
At-home testing kits are accurate enough for the casual gardener and lawn enthusiast. If you’re looking for something more specific, you should consider a full nutrient analysis. Your local cooperative extension office can provide you with the soil testing kit and perform the analysis.
How to Test Your Soil
The testing process will vary slightly depending on the kit you purchase, but the general process will be the same.
- Clean the tools you will be using to collect the sample.
- Dig 5 holes about 6 inches deep each.
- Take about ½-inch slice from the side of each hole, and place the soil in a bucket.
- Mix the samples together and spread the soil on newspaper to dry out.
- Collect the needed amount from this mixture.
Pro Tip: If your sample has lots of earthworms wiggling about, this means your soil already has a strong composition of organic matter.
What Are Soil Amendments?
A soil amendment is anything added to the soil to improve nutrients, water retention, pH levels, air intake, and absorption. The goal of mixing amendments into your soil is to improve the environment for healthy root growth.
There are two categories of soil amendments:
- Organic additives are derived from something that was once alive. This includes manure, compost, and wood ash.
- Inorganic additives are either mined or man-made. Common inorganic materials include lime, vermiculite, sand, and perlite.
While mulch can be used to improve soil properties, it is not considered an amendment since it sits atop the soil.
Best Soil Amendments
There are many options for amendments depending on what your soil test indicates. Cover crops and composted manure are great options, but not always necessary for home gardeners.
Most residential soils will benefit from one of the following common amendments:
- Compost: Decayed kitchen scraps and other plant materials such as wood chips, bark, and sawdust.
- Plant material: Straw, grass clippings, peat moss, and shredded leaves.
- Topsoil: Additional soil that provides volume and is usually accompanied by lime and other amendments
Some gardens will require very specific adjustments and might require one of the following:
- Gypsum: Improves water absorption, reduces erosion, and helps garden plants absorb nutrients.
- Lime: Lime for lawns (not the sour green fruit) raises the pH level of acidic soil.
- Sulfur: Lowers the pH level of alkaline soil.
Types of Soil
There are three broad classifications of soil based on the rock particles it contains. Texture can be amended by adding organic matter such as compost or plant material.
- Clay soil consists of fine particles that are slow to absorb or drain moisture. It typically becomes baked and dry in the summer heat and waterlogged in winter.
After an initial amendment of 3 or 4 inches of compost, add an additional inch each year. You can amend the soil structure by adding fine mulch bark or straw.
- Silt soil is characterized by small particles and a floury feel. Silt holds on to moisture and nutrients fairly well.
Improve the texture by adding 1 inch of organic matter each year.
- Sandy soil has large particles that drain quickly. Sandy soil warms quickly but does not hold on to nutrients.
Three to 4 inches of compost will help water retention. Adding 2 inches of compost each fall will help you maintain a loam.
- Loam soil absorbs and drains water well, provides adequate oxygen to roots, and is rich in organic matter. Loamy soil will crumble easily and not form a ball when squeezed.
Loam is the ideal soil type for all gardening projects.
To correct the soil pH, you will need to add lime or sulfur. The amount you use depends on the current pH of your soil and the pH you’d like to reach. Most plants do best with a pH of 6 to 7.
How to Improve Your Soil
Garden soil should be about 5% organic matter. Organic matter ensures the release of nitrogen is adequate to support your lawn and plants without additional fertilizers.
When should you add soil amendments?
Add organic amendments in the fall, allowing earthworms to work it deeper into the ground by spring.
If you need to amend in the spring, do so as soon as the soil is dry enough to work with.
- Spread about 2 inches of organic matter across the vegetable garden or flower bed.
- With a rake or garden fork, thoroughly mix the organic material into the top 6 inches of soil.
- Water the area and check the moisture.
- Wait about two weeks before planting.
- Rake the soil, level it, and remove any unwanted debris before installing your plants.
Healthy soil is the first step to healthy and lower maintenance gardens.
FAQ About Testing Your Soil
What elements should I keep in mind when amending my soil?
- How often should I test the soil?
Frequent testing will help you determine if your amendments are working. Once you get the soil where you want it, you only need to test every couple of years.
- Where in my yard should I take the sample from?
Samples should come from near the plant roots. This could be a specific garden bed or a tree’s root system. To assess the soil quality in your lawn, take samples from different areas based on conditions.
- What elements should I keep in mind when amending my soil?
Phosphorus: Promotes root growth, plant maturity, and winter hardiness.
Potassium: Disease resistance, drought tolerance, and plant strength.
Calcium: Improves soil structure, aeration, and water retention.
Magnesium: Improves plant growth and chlorophyll production.
While testing the soil in your yard might not be an overwhelming task, amending it might. If you find yourself short on time, patience, or ideas, consider calling on a local lawn care professional. The pros know just what to do to keep your soil healthy and when to do it, allowing you to simply enjoy the outcome.