The Jar Test: Soil Texture Analysis
Materials: ★☆☆ Easy to get from supermarket or hardware store
Difficulty: ★☆☆ Can be easily done by most teenagers
Safety: ★☆☆ Minimal safety procedures required
Categories: Soil and Erosion
Alternative titles: Simple Soil Composition Analysis
Summary
The jar test is a simple soil analysis technique that helps determine the proportions of sand, silt, and clay in a soil sample. By shaking soil with water and allowing the particles to settle, you can visually analyze soil texture and apply the results to gardening, farming, or permaculture practices.
Procedure
- Collect soil samples from about 6 inches below the surface, removing rocks, roots, and debris.
- Fill a clear glass jar about one-third full with soil.
- Add water to near the top of the jar, leaving some space.
- Secure the lid and shake the jar vigorously for 60 seconds.
- Place the jar on a flat surface and allow it to settle undisturbed for 1–3 days until the water clears.
- Observe the layers that form: sand settles first (minutes), silt settles next (hours), and clay remains suspended the longest (1+ day).
- Use a ruler to measure the thickness of each layer and calculate percentages of sand, silt, and clay.
- Use a soil texture triangle to classify the soil type (e.g., sandy, silty, clay, or loam).
Links
Testing Soil Texture - Mason Jar Soil Test - Growit Buildit:
The Jar Test - Decoding your Soil's Texture - Milkwood:
📄 The Jar Test: A Simple DIY Soil Texture Analysis - Building a Food Forest: https://buildingafoodforestscotland.com/2025/03/29/the-jar-test-a-simple-diy-soil-texture-analysis/
Variations
- Compare soil samples from different garden beds, fields, or natural locations.
- Use distilled water instead of filtered water for more accurate results.
- Perform the test with added organic matter to see how soil composition changes.
Safety Precautions
- Wash hands thoroughly after handling soil.
- Use clean jars to prevent contamination.
- Keep jars sealed during shaking to avoid spills.
Questions to Consider
- Why does sand settle faster than silt and clay? (Sand particles are larger and heavier.)
- How does soil texture affect plant growth? (It influences water retention, aeration, and nutrient availability.)
- Which soil type holds nutrients the best? (Clay, because it has a high surface area and cation exchange capacity.)
- Which soil type drains the fastest? (Sandy soils, due to large pore spaces between particles.)
- Why is loam often considered the best soil for gardening? (It balances drainage, aeration, and nutrient retention.)