How to Test a Soil Jar

A soil jar test is a simple and inexpensive way to determine the texture of your soil. This information can be helpful for gardeners who want to improve the health and productivity of their soil.

Key Facts

  1. Gather materials: You will need a quart jar with a lid, loose soil (clod- and rock-free), Calgon or granular dishwashing detergent, and water.
  2. Prepare the soil sample: Fill the quart jar with approximately one-half cup of loose soil. Make sure the soil is free of clods and rocks.
  3. Add Calgon and water: Add one heaping tablespoon of Calgon or granular dishwashing detergent to the jar. Then, add 3½ cups of water to the jar.
  4. Shake the jar: Cap the jar tightly and shake it for five minutes. Alternatively, you can invert the jar multiple times to mix the soil, Calgon, and water.
  5. Let the jar sit: After shaking, allow the jar to sit undisturbed for at least 24 hours. This will allow the soil particles to settle and separate.
  6. Analyze the results: After 24 hours, you will notice distinct layers in the jar. The bottom layer will be sand, followed by silt, and then clay. The proportions of each layer can give you an idea of the soil texture.

It’s important to note that this method provides a rough estimation of soil texture and is not as accurate as laboratory testing. However, it can still give you a general idea of the soil composition in your garden.

Materials

  • Quart jar with a lid
  • Loose soil (clod- and rock-free)
  • Calgon or granular dishwashing detergent
  • Water
  • Ruler

Procedure

  1. Fill the quart jar with approximately one-half cup of loose soil. Make sure the soil is free of clods and rocks.
  2. Add one heaping tablespoon of Calgon or granular dishwashing detergent to the jar.
  3. Add 3½ cups of water to the jar.
  4. Cap the jar tightly and shake it for five minutes. Alternatively, you can invert the jar multiple times to mix the soil, Calgon, and water.
  5. Allow the jar to sit undisturbed for at least 24 hours. This will allow the soil particles to settle and separate.
  6. After 24 hours, you will notice distinct layers in the jar. The bottom layer will be sand, followed by silt, and then clay. The proportions of each layer can give you an idea of the soil texture.

Interpretation

The texture of your soil is determined by the relative proportions of sand, silt, and clay.

  • Sand: Sand particles are the largest and most visible. They are gritty and do not hold water well.
  • Silt: Silt particles are smaller than sand particles but larger than clay particles. They are smooth and hold water better than sand.
  • Clay: Clay particles are the smallest and least visible. They are sticky and hold water very well.

The ideal soil texture for most plants is a loam, which is a mixture of sand, silt, and clay in roughly equal proportions. Loam soils are well-drained and have good water-holding capacity.

If your soil is too sandy, it will drain too quickly and not hold enough water for plants. You can improve the water-holding capacity of sandy soil by adding organic matter, such as compost or manure.

If your soil is too silty, it will hold too much water and not drain well. You can improve the drainage of silty soil by adding sand or gravel.

If your soil is too clayey, it will be difficult to work and will not drain well. You can improve the workability and drainage of clayey soil by adding organic matter, such as compost or manure.

Conclusion

A soil jar test is a simple and inexpensive way to determine the texture of your soil. This information can be helpful for gardeners who want to improve the health and productivity of their soil.

References

FAQs

What materials do I need to conduct a soil jar test?

You will need a quart jar with a lid, loose soil (clod- and rock-free), Calgon or granular dishwashing detergent, water, and a ruler.

How do I prepare the soil sample for the test?

Fill the quart jar with approximately one-half cup of loose soil. Make sure the soil is free of clods and rocks.

How do I conduct the soil jar test?

Add one heaping tablespoon of Calgon or granular dishwashing detergent to the jar. Then, add 3½ cups of water to the jar. Cap the jar tightly and shake it for five minutes. Alternatively, you can invert the jar multiple times to mix the soil, Calgon, and water. Allow the jar to sit undisturbed for at least 24 hours.

How do I interpret the results of the soil jar test?

After 24 hours, you will notice distinct layers in the jar. The bottom layer will be sand, followed by silt, and then clay. The proportions of each layer can give you an idea of the soil texture.

What is the ideal soil texture?

The ideal soil texture for most plants is a loam, which is a mixture of sand, silt, and clay in roughly equal proportions. Loam soils are well-drained and have good water-holding capacity.

What can I do if my soil is too sandy?

If your soil is too sandy, it will drain too quickly and not hold enough water for plants. You can improve the water-holding capacity of sandy soil by adding organic matter, such as compost or manure.

What can I do if my soil is too silty?

If your soil is too silty, it will hold too much water and not drain well. You can improve the drainage of silty soil by adding sand or gravel.

What can I do if my soil is too clayey?

If your soil is too clayey, it will be difficult to work and will not drain well. You can improve the workability and drainage of clayey soil by adding organic matter, such as compost or manure.