Cappers Farmer Blogs > Our Fair Field

It's Sedimentary, My Dear Watson

Renee-Lucie Benoit"Spring has sprung. The grass is riz. I wonder where the flowers is?"

Answer: They're everywhere!

poppies 

In the meantime I'm getting ready to plant my victory garden. First I need to see what I'm working with.

Do It Yourself Soil Sediment Test

Soil is where the garden starts. If you don't have good soil you're not going to have healthy plants. Healthy plants resist insects and disease. Plant health begins with what they're sitting in.

People used to think all you had to do was add fertilizer. Then compost became all the rage. All that is good and fine, but the best approach is to know what you have. Then you can amend according to what you actually need without guessing so you'll be gardening more accurately. Take a tip from commercial growers. They know their soil inside out.

On our new place I have decent soil to work so I'm getting with the program. When I put the fork to the soil it goes in easy and turns easy. I'm so happy after 4 years of terrible, awful, very bad, no good, heavy clay soil.

This simple, low cost test will help us get off to the right start for the rest of the garden.

What You Need:

straight-sided, flat-bottomed clear jar

something to measure with

dish soap (optional)

calculator (if you're fractionally impaired, as I am)

First, dig a soil sample from the plant root zone in the area your garden will be. Discard any plant material as best you can. Dig enough to full the jar by 1/3.

 soil in jar

If you find any worms, of course, remove them and put them back in their habitat! Yay, worms! Crumble the soil and pick out any pebbles or roots, etc.

Fill the jar to 1/3. I add a little tiny drop of dish soap. This helps get the soil particles wet and separated but this step is optional. Now fill the jar with water within an inch of the top, put the lid on tight, and give it a good shake to get all the soil wet and suspended. Keep shaking until nothing is left on the bottom or sides. Set the jar on a flat surface and watch it settle.

Sand settles first because the particles are large and therefore heavy.  The sandy layer will look coarse.  If you look close you will actually see the sand particles. The silt and clay layers do not look coarse. They will just be a color. Dark brown or light brown. Mark where the sand ends and the next layer begins.

Silt is the next layer to settle out. This will take about an hour. You will notice it is a different color. Most often it is darker. Mark where the silt layer begins and ends.

Clay is the slowest of the soil particles to settle. Heavy clay layer will settle out in a day. Finer clay might take two days. You can let the clay settle for up to a week. It all depends on your soil.

Measure the depth of each layer and the total soil depth. These measurements are used to calculate the percentage of each soil component.

layers

My jar shows 1-1/2 (1.5) inches of sand, 1/2 (.5) inch of silt, and 1/4 (.25) inch of clay, for a total of 2-1/4 (2.25) inches. Divide each particle depth by the total soil depth to get the percentages:

1.5 divided by 2.25 = .66 or 66% sand

.5 divided by 2.25 = 0.22 or 22% silt

.25 divided by 2.25 = .11 or 11% clay.

Interpreting the Test

Using a soil triangle chart, I am able to figure out what kind of soil structure I am dealing with. It gives me a foundation to work from for how to amend my soil as needed. Here what the triangle chart looks like, you can find all sorts of variations on the web.

sediment 

Here's how I use the chart. (For fun you can download an excel version from the USDA that will calculate it for you).

Find the numbers that correspond to your percentages. You're basically drawing a line from your percentage number to where the 3 percentage numbers intersect. From the clay side draw a line from left to right until the intersection. For the silt draw from right to left until intersection. For sand draw from bottom to top until intersection. My test results in sandy clay loam.

So I'll be adding compost, manures, bio-char, and old mulch to enhance the moisture holding properties.

What will you do with your soil?