Steve @ Celtic Farm
Flower Farmer | Master Gardener | Earth Scientist
Earthworm Test for Soil Health
Thought I'd share a portion of a piece I am writing on 4 DIY soil tests you can do to determine the health of your soil.The presence of earthworms in your garden soil is a strong indicator of its health and fertility. The earthworm test is a simple yet effective way to assess the biological activity and overall quality of your soil. Here’s how it works and what the results mean.
How to Conduct the Earthworm Test
- Timing and Conditions Ensure the soil temperature is at least 55 degrees Fahrenheit and is moderately moist. These conditions are ideal for earthworm activity.
- Digging the Soil Carefully dig a hole about one foot deep and one foot across. It’s best to do this gently to minimize harm to any earthworms present.
- Counting Earthworms As you remove the soil, sift through it and count the number of earthworms you find. After counting, replace the soil in the hole.
Now that we have our worm count, we can apply that to general standards and understand the health of our soil.
- High Earthworm Count– If you find 10 or more earthworms in the soil sample, it’s a strong indication of healthy, fertile soil. Earthworms are beneficial for the soil as they aerate it while moving through, improve its drainage, and enhance nutrient availability by breaking down organic matter.
- Low Earthworm Count– Fewer than 10 earthworms might suggest that your soil lacks sufficient organic matter or has issues with acidity or alkalinity. It could also indicate compacted or poorly aerated soil, which is not conducive to earthworm activity.
How do earthworms help the soil?Gardener Tip: Earthworms, commonly found in gardens and soil, are soil-dwellers that burrow deeply and help aerate and mix the soil layers, thus enhancing soil structure and nutrient distribution. On the other hand, vermi-composting worms, like red wigglers, are surface-dwellers and thrive in decomposing organic matter rather than soil. They are used in vermi-composting systems to break down kitchen scraps and organic waste into nutrient-rich compost, known as worm castings. Unlike earthworms, vermi-composting worms prefer a controlled environment and are ideal for indoor or small-scale composting.
Earthworms are often called ‘nature’s tillers’. Their movement through the soil creates channels that improve aeration and water infiltration. They feed on organic matter, breaking it down into more accessible forms for plants, thereby enriching the soil. Their castings (excretions) are also rich in nutrients, acting as a natural fertilizer. A thriving earthworm population is a good sign of organic matter richness and a balanced soil ecosystem, which is fundamental for healthy plant growth.
The earthworm test provides a straightforward way to gauge the biological health of your soil. A garden with a healthy earthworm population is likely to have well-aerated, nutrient-rich soil, which is a key component in supporting vigorous plant growth and a successful garden.