Everybody knows earthworms work great on our hook when fishing. However, have you ever thought about how important earthworms or nightcrawlers are to your soil’s quality? Probably Not, but you should. According to the USDA, perhaps no other living organism in the soil is as important as an earthworm in helping to increase soil health. They are affectionately called the “original farmer”. Therefore, earthworms play a critical role in our soil quality which directly leads to better plants and a bigger harvest. The benefits of earthworms in garden soil are profound!
Quick Facts
They are obviously harmless worms but are beneficial residents in our soil.
Physical Characteristics
Earthworms don’t have lungs; they breathe through their skin. They also lack eyes, so instead use receptors in their skin to sense light and touch. They consist of a muscular hollow tube with a mouth at one end and a butt at the other. The worms range between 90 and 150 different segments, with five hearts, a circulatory system, a mucus system and a brain and nervous system. It also has lots of kidney type organs, which neutralize food. It has a gizzard, which grinds food. They are sensitive to temperature, light, vibration and moisture. The night crawler has an average life span between six to nine years and has been reported to live up to 20.
Earthworm (Leni – Pexels)
Movement
Earthworms use their segmented, cylindrical body to move forward or backwards using its muscles. It uses its ’round’ muscles squeezed together to make it long and thin, then short to fat, pushing their body along. SETA, the tiny bristles from each segment of the worm, dig into the surrounding matter to keep the worm from slipping. They excrete mucus which helps them slide along.
Earthworms burrow up to 6 and a-half feet underground. Typically, they only venture above the surface at night. Hence, that’s how they earned the nickname ‘night crawlers’.
Reproduction
Worms can begin breeding once they reach maturing from 50 – 90 days. Earthworms are hermaphrodites, meaning an individual worm has both male and female reproductive organs. They can perform both male and female functions and mate sometimes weekly. The mating process takes around 24 hours.
Species
There are close to 200 species of earthworms that live in the US. Over 50 of those are invasive. Some earthworm species were accidentally brought over on European ships as ballasts and in potted plants during the 1700 and 1800s.
Food/Eating
Earthworms eat a lot. Daily, they consume about a third of their body weight in food. Their meal of choice is soil with compost and decaying organic matter present.
Benefits
How do earthworms help the garden? What are the benefits of earthworms in garden soil. Earthworms increase soil aeration, infiltration, structure, nutrient availability, improved drainage, and plant growth.
Improved Nutrient Availability
Earthworms’ breakdown dead and decaying organic matter into rich humus soil, thereby supporting plant growth. Their digestive system concentrates the organic and mineral components in the feed they eat. That means their castings end up being richer in available nutrients then the soil around them. Earthworm castings contain nitrogen, phosphorus, potassium, and magnesium which increases soil fertility. Nitrogen in castings is readily available to plants. Earthworm casts also contain microorganisms which increase in abundance as organic matter is digested in their intestines. The cycling of nutrients from organic matter and the increase in microorganisms facilitates plant growth.
Improved Drainage
When they move through the soil eating, earthworms create channels or burrows. This loosens and aerates the soil and improved soil drainage. Soils with earthworms drain up to 10 times faster than soil without night crawlers. In raised beds, where worm populations are high, water infiltration can be up to 6 times greater than traditional gardening rows.
Improved Soil Structure
Earthworm casting combined with binding agents released by earthworms “glues” together soil particles together in water-stable aggregates. These can store moisture without dispersing. This improves soil structure and increases soil stability. Earthworm burrows also increase soil porosity increasing the amount of air and water that get into the soil. Increased porosity helps lower the density of the soil which increases root development. By density of the soil, it just means how compressed the soil is.
How to Attract and Feed Earthworms
We now know the benefits of earthworms in garden soil. We want to preserve and nurture earthworms as they are God’s original farmers. How do we do this? How do we attract them?
PH of Soil
Ensure soil PH is above 4.5. This can be adjusted by adding some lime. However, please know your PH before adding anything to the soil. Earthworms need a continuous supply of calcium which are absent in soils with a low PH.
Organic Matter/Compost
Next, Increase Organic Matter. As stated earlier, earthworms feed on soil and decomposing plant remains. Mulching, especially with leaves is a great way to attract and feed earthworms. Turn the leaf mulch into the top of your soil at the end of the season. As it decomposes, it not only helps the soil but provides nutrients for earthworms, which also helps your soil.
Eliminate Fertilizers and Fungicides
Reduce use of some Fertilizers and Fungicides. Highly acidifying fertilizers such as ammonium sulphate and some fungicides reduce earthworm numbers so avoid using if possible.
Keep Soil Moist
Keep soil moist. Worms can lose 20% of their body weight each day in mucus and castings. They need a continuous supply of moisture to live. Thus, another good reason to have leaf mold or some other mulch in the garden beds.
Adequate Draining
On the flip side of that, we also need to ensure the bed has adequate drainage. The soil does need to be aerated and not heavily laden with water. Raised beds are a great way to ensure you have adequate draining.
Soil Compaction
Reduce Soil Compaction. Another big reasons for raised bed gardens is the advantage it provides to keep the soil loose and friable, and therefore not compacted. With raised beds, there is no reason to step on the soil compacting it. Earthworms do not like to be walked on or living in compacted soil.
Reduce cultivation
Pulling out the tractor or till every season does break up the soil but also kills many of the earthworms. This is another advantage of the raised bed type of gardening. I do work in amendments to my soil about 4 to 8 inches deep. I’m sure a few earthworms are harmed but nowhere near as many as plowing or tilling.
The benefits of earthworms in garden soil are clear and easy to see. Earthworms truly are the original farmer. Do what you can to attract and not kill them such as tilling your soil.
If you like this content, you will love my Spring Garden Planning Checklist post!
Happy Gardening,
Darrell.
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