Last updated on October 23rd, 2023 at 08:50 pm
Almost everyone finds them disgusting: earthworms! Yet they help plants to thrive particularly well. All about the useful little helpers – and how best to attract them.
Earthworms are tunnel builders
“When the layman speaks of the earthworm, he usually means the eelworm or dew worm,” says Helmut Schimmel, a certified gardener and book author from Gera. This soil dweller from the tribe of annelids is a tunnel builder. Julian Heiermann of the Nature and Biodiversity Conservation Union of Europe (Nabu) explains the origin of the name earthworm by saying that the worms are mainly visible when it has rained heavily.
The earth is improved
The earthworm mixes, aerates and stabilizes the soil. “In this way, it counteracts soil erosion,” explains Schimmel. In addition, the animals improve the soil with their excretions. “They are important for soil life because they nibble on everything that lies dead in and on the soil,” adds Heiermann. But earthworms don’t just eat dead material; they pull leaves into their tunnels, allowing plant material to go directly deep into the soil and pass over as it decomposes. “Sometimes you see leaf litter deep in the soil,” Heiermann says.
Valuable plant nutrient is produced
The soil dwellers have an unusual method of getting around, explains the zoologist: “Earthworms virtually eat their way through the soil.” Since the earthworm has no teeth, it feeds on a fine, squishy mush of organic material that is decomposing and already predigested by microorganisms, explains Schimmel, the textbook author. “In the process, it also digests bacteria, fungi and minerals,” adds Heiermann. In the earthworm’s gut, mixing of organic and mineral material occurs. Its excrement is also known as the clay-humus complex, known as a valuable plant nutrient. It promotes soil fertility.
Mineral fertilizers expel the worm
The droppings are deposited down to deep soil layers, but also as small piles on the lawn. The latter sometimes annoys amateur gardeners, as they are afraid the lawn will no longer look nice. “Actually, however, this is a good sign,” explains Heiermann. This is because the earthworm’s excrement is an excellent fertilizer. Hobby gardeners have to be careful when they intervene in the composition of the soil themselves: “The earthworm doesn’t like mineral fertilizers,” explains Heiermann. If you use it, the earthworm makes itself scarce, and as a result the remaining soil life also declines.
Compost worm produces fertile soil
In addition to earthworms, there is the compost worm, also known as the manure worm or humus worm. Its reddish color is typical. “It is a type of domesticated worm that is used by humans specifically for composting,” says Schimmel, the book’s author. The worm does not build tunnels, but creates fine, crumbly soil. “This worm humus is the most fertile compost soil I know of.” Composting with these worms has one main advantage: conversion starts at low substrate temperatures, which suppresses rotting processes.
How to attract the worms
The gardener can ensure that “the little brownies, i.e. microorganisms and earthworms, get enough food” with the help of mulch and foundation as well as the cultivation of catch crops in winter and the observance of crop rotations on the bed, explains garden expert Schimmel. He recommends attracting the compost worm with its favorite foods: coffee grounds, onion waste and manure.