The Squeeze Test is a simple test for judging the quality and composition of garden soil. The test should be carried out on moist but not wet soil. If the soil to test has not received any rainfall in recent weeks, water the soil 1 night prior to the test if possible.
The Squeeze Test
Step 1
Dig a hole in the ground to a depth of approximately 100-150mm.
Collect a handful of loose soil.
Step 2
Using your hands, form the soil into a tight ball – there should be no air pockets in the ball
If your sample is largely comprised of sand then you may not be able to form a ball. Feel the texture of the soil as you form the ball – take note of whether it feels smooth, sticky or gritty
Step 3
Take the resulting ball of soil between thumb and forefingers
Step 4
Begin to slowly apply pressure to the ball of soil using your thumb and fore fingers.At this point you should start to notice a change in the ball.
If the soil is sandy – your ball will feel gritty, and may disintegrate at the slightest pressure
If the soil is clay – your ball will feel sticky and smooth, and will compress with little to no surface cracks, or loss of material.
If the soil is loam – cracks should start appearing on it’s surface, but it will hold together, loosing some material as pressure is applied.
Step 5
Continue to apply gentle pressure to the ball, and continue to observe the changes in the sample as more pressure is applied.
Step 6
Once your thumb and forefinger are close to touching through the soil, stop applying pressure, and look at the soil that remains in your hands (if any).
Step 7
Consider the texture, and the amount of change in the shape of the ball as you conducted the test.
If the ball fell apart quickly and is gritty then you have a large quantity of sand in the soil. Adding organic matter (such as compost) is advised to add humus, nutrients and water retentive capability.
If the ball squished, loosing little to no material, and is sticky and smooth in texture, then the sample is high in clay, and the soil should be remediated with organic matter and cultivation to add air and structure to the soil. Gypsum may be needed to break up the texture if the clay is particularly heavy.
If the ball lost material at a consistent rate, is dark and rich then the soil is likely loam, rich in humus and nutrients leading to optimal plant health. Adding compost or organic matter will enrich the soil further as nutrients deplete over time.