Soil Texture Test: Sand, Silt, or Clay

A common mantra in native gardening is “right plant, right place.” This saying sprouts from the idea that gardeners and landscapers can avoid common pitfalls by ensuring that they choose plants that fit both the needs and conditions of the planting site:

• How big is your gardening space?
• What is the sun exposure throughout the day?
• What is your hardiness zone?
• How do you want to use the space?

And finally,

• What type of soil does your garden have?

You can get an in-depth soil test from your local university extension, but there are also some basic at-home tests you can perform. We will show you how to use common household items to determine the soil texture you’re working with in order to choose the “right plants” for the “right place” in your garden.

The Jar Test

This will test for soil texture and give you a pretty good idea of the percentage of sand, silt, and clay in your soil. Here’s what you will need:

• A clear, straight-sided jar with a lid (mason jars are a good option)
• A trowel
• A large tray/container if you’re sampling a large area
• A ruler
• A timing device (watch, phone, egg timer, etc.)

If the gardening space you want to test spans a wide area, you have two options. First, for a general overview of the type of soil in your garden, you can gather soil from multiple areas, mix them, and draw your soil sample from the mixture. Your second option is to do individual tests for separate garden beds or areas. It’s entirely up to you!

Step 1: Gather your soil

Using your trowel, dig down to root level (approximately 6 inches). Remove enough soil to fill between 1/3 and ½ of your jar. Remove any large impediments (rocks, roots, leaves, worms, etc.). Fill the jar about 80% with water, giving the soil time to soak up the water.

Step 2: Shake!

Put the lid on your jar and shake thoroughly for 3 minutes.

Step 3: Sit and measure

Set your jar down and set your timer for 1 minute. After 1 minute, use your ruler to measure the sediment at the bottom of the jar. This is the amount of sand in your soil. Set your timer for 4 minutes. After 4 minutes, use your ruler to measure the sediment that has settled on top of the sand layer. This is the amount of silt in your soil. Wait 48 hours. After 48 hours, measure the final layer. This is the amount of clay in your soil. After each step it is also a good idea to mark your jar with tape or a marker as the layers settle.

Example

Nursery Entrance Irrigation Pond At Direct Native Plants we took soil samples from two different locations: to the left of the nursery entrance and in front of our irrigation pond. As you can see in the photos, both areas are primarily sandy. The entrance is 62% sand/30% silt/8% clay, and the irrigation pond is 77% sand, 15% silt, and 8% clay. As a result, we will be choosing plants that are known to perform well in sandy soil.

There is a Native Plant for That!

A good soil mixture is approximately 20% clay, 40% silt, and 40% sand. If your sample is outside of these parameters, there is a native plant for that! Plants that are native to your region tend to be your best option for meeting the conditions that already exist in your garden. Natives are adapted to local conditions, and if you choose the right plants, there is less need to amend your soil.

Native Plants That Can Tolerate Sandy Soil

Sandy soils drain quickly and tend to be drier than clay or loamy soils.

• Witchhazel
• Black Chokeberry
• Northern Bayberry
• Serviceberry
• Northern White Cedar
• Red Columbine
• Wild Ginger
• Smooth Aster
• Purple Coneflower
• Ox-Eye Sunflower
• Wild Bergamot

Native Plants That Can Tolerate Clay Soil

Clay soils do not drain quickly and tend to stay wet longer that sandy or loamy soils.

• Black Chokeberry
• Wild Ginger
• Purple Coneflower
• Witchhazel
• Wild Bergamot
• Spotted Joe Pye Weed
• Sweet Pepperbush
• Winterberry
• Buttonbush

Please note, the suggestions above are not extensive; they are simply meant to be a starting point. Looking for a more comprehensive list of plants by soil type? Check out your local university extension for native plant lists and resources. If you’re in the Maryland area, here is the University of Maryland’s list of native plants categorized by soil condition. The US Fish and Wildlife Service’s Native Plants for Wildlife habitat and Conservation Landscaping is also a useful source. Want to stay up-to-date with all of our Native News? Sign up for our email newsletter!