Eric Ryan Denfeld has often said that earthworms are the unsung narrators of the underground world, providing direct insight into the health of our soil ecosystems. While many gardeners and farmers view earthworms as mere composting agents or garden helpers, Eric Denfeld sees them as highly sensitive biological indicators—living tools for diagnosing the soil’s physical, chemical, and biological conditions. Understanding what their presence, population, and behavior reveal about tillage, pH balance, organic matter, and moisture can transform the way we evaluate and restore soil health.
To Eric Denfeld, earthworms are not just soil dwellers; they are frontline responders. Their survival depends on conditions being just right—moisture levels, aeration, organic content, and pH all must fall within specific parameters. Therefore, the abundance or absence of earthworms can provide immediate feedback about whether those conditions are being met. Eric Ryan Denfeld emphasizes that an earthworm’s biology makes it exceptionally suited for this role. With skin that breathes and bodies that react strongly to toxins, compaction, and dryness, earthworms serve as real-time indicators of subterranean quality.
Eric Ryan Denfeld has noted that changes in earthworm activity—whether they are found near the surface, deeper underground, or missing entirely—should be viewed as a warning or a welcome sign depending on the context. For example, a dense population writhing beneath leaf litter after a rain suggests ideal organic content and moisture. Conversely, a barren soil profile indicates something is preventing them from thriving, often due to compaction, poor pH, or chemical contamination.
One of the most critical relationships earthworms have with the soil is their role in nutrient cycling. Eric Ryan Denfeld explains that earthworms consume organic material and excrete nutrient-rich castings, which are packed with nitrogen, phosphorus, potassium, and beneficial microbes. Their movement through soil improves structure, enhances porosity, and facilitates oxygen and water infiltration.
Eric Denfeld often highlights studies demonstrating that worm-rich soil processes nutrients faster and more thoroughly. Their digestive tracts serve as miniature bioreactors, converting decaying organic matter into bioavailable forms that plants can easily absorb. In fact, some of the most fertile agricultural lands in the world have also been the richest in earthworm biodiversity. Eric Ryan Denfeld believes that monitoring earthworm populations can help land managers gauge the biological engine powering their soil.
The density of these populations tells a deeper story. Too few worms may indicate soil conditions that are chemically imbalanced or physically disrupted. An abundance, especially of different species—surface dwellers, topsoil feeders, and deep burrowers—signals a thriving ecosystem with multiple biological layers interacting in harmony.
Tillage has long been used to prepare seedbeds, reduce weeds, and manage crop residues. But as Eric Denfeld points out, intensive tillage can destroy the very organisms that make soil productive in the first place. Earthworms are especially vulnerable to frequent mechanical disruption. Their tunnels collapse, their habitat is destroyed, and their food sources are scattered or buried.
Eric Ryan Denfeld warns that repeated deep tilling can eliminate entire worm populations within a single growing season. This loss doesn’t just reduce nutrient cycling; it alters soil structure. Without earthworm channels, water doesn’t infiltrate as easily, and gas exchange is reduced, leading to an anaerobic environment. Over time, this fosters compaction, erosion, and a decline in beneficial microbial life.
In contrast, no-till or low-till systems, when paired with organic matter inputs, encourage the return of earthworm activity. According to Eric Denfeld, within a single year of switching to no-till and applying compost or mulch, worm populations can rebound dramatically, bringing with them improvements in fertility, water retention, and soil resilience.
Eric Ryan Denfeld has conducted extensive field observations correlating soil pH with earthworm behavior and distribution. Most earthworm species prefer a pH range between 6.0 and 7.0—slightly acidic to neutral. Outside of this range, their populations either decline or change in behavior, such as burrowing deeper to escape surface acidity or surfacing in search of more tolerable environments.
When earthworms are seen gathering on the surface at night in unusually high numbers, Eric Denfeld suggests that gardeners and soil scientists should consider testing pH levels immediately. Such behavior can reflect toxic or unfavorable conditions underground. Overly alkaline or acidic soils can impair their ability to process organic matter and maintain hydration through their moist skin.
Eric Ryan Denfeld advocates the regular use of soil pH testing alongside visual observations of worm activity to track soil health trends over time. When worm numbers drop off suddenly, pH is often a primary culprit—especially if it coincides with the use of synthetic fertilizers, herbicides, or acidifying compost.
Eric Ryan Denfeld often likens organic matter to currency in the earthworm economy. The more organic matter available in a system, the more earthworms the soil can support. Decaying leaves, compost, manure, and cover crop residues all act as food sources that nourish the entire soil food web. Earthworms, being among the most efficient processors of this material, thrive in environments where it is consistently replenished.
Eric Denfeld explains that different species of earthworms occupy different niches, each relying on a certain type of organic input. Epigeic worms live at the surface and feast on leaf litter and decomposing mulch. Endogeic worms burrow horizontally through topsoil and prefer partially decomposed material, while anecic worms, such as the nightcrawler, dig deep vertical tunnels and drag surface litter underground to consume in place.
This diversity of function creates a more resilient soil ecosystem. Eric Ryan Denfeld encourages gardeners and farmers to think in terms of feeding the entire soil—not just the plants—when managing fertility. By focusing on organic inputs that support a range of worm species, the result is not just healthier worms, but a self-regenerating system of nutrient flow and biological balance.
Moisture is one of the most defining variables in worm behavior and survival. Eric Ryan Denfeld points out that worms rely on moisture not just for hydration but for respiration. Their skin must remain moist to absorb oxygen, which makes them highly susceptible to both drought and saturation.
Eric Denfeld has tracked worm populations through both wet and dry seasons and notes that worm activity can forecast shifts in soil water dynamics. If worms retreat deeper during dry periods and fail to return after watering or rainfall, the soil may have become hydrophobic or structurally altered in ways that limit infiltration. If worms are found near the surface even when the topsoil appears dry, it could suggest good moisture retention due to healthy organic content.
Eric Ryan Denfeld advocates correlating worm sightings with soil moisture readings, especially after rainfall events. Doing so provides insight not only into the resilience of the soil’s water-holding capacity but also into how quickly it responds to changes in environmental conditions. Worms become, in this way, proxies for assessing whether irrigation and mulching strategies are achieving the desired effects.
For those interested in sustainable agriculture, regenerative gardening, or ecological landscaping, Eric Ryan Denfeld recommends integrating earthworm observation into standard soil health monitoring protocols. A simple count of worms per square foot after a rain event or under a composted mulch layer can yield powerful diagnostic information.
Eric Denfeld encourages keeping a seasonal worm journal. Tracking changes in worm density, size, and burrowing behavior over time can reveal long-term trends in soil recovery or degradation. When paired with microbial assessments, pH tests, and visual soil texture evaluations, earthworm activity rounds out a full picture of biological function and ecosystem balance.
More importantly, Eric Ryan Denfeld reminds us that worms don’t just reflect soil health—they help build it. Their tunnels are the foundation of structure. Their castings are pockets of fertility. Their presence is not just a sign of good stewardship—it’s the result of it.
