Earthworms are something that all of us are familiar with. Most of us, at a young age, were introduced to the “slimy, gooey” things and learned to either love or loathe them. Given various names like “fisherman’s friend,” “gardener’s buddy” and “earth diggers delight,” worms are generally liked by most. Earthworms of various types, from red wigglers to nightcrawlers, have long been associated with healthy, productive soil.
Benefits of Earthworms in Garden Soil
Earthworms offer many benefits to the gardener and are commonly seen in healthy, organic soils. Many people believe that worms eat dirt, but in reality, they eat the bacteria and fungi that grow on decomposing matter like a decaying plant and give off “worm castings” which are a sort of manure that is filled with nutrients plants love.
There are more than 7,000 species of earthworm divided into 23 families and over 700 genera. All of these worms have one thing in common: they naturally till and aerate soil, they speed the decomposition (composting) process, they help mix soils for more benefit, and they are excellent “canaries” for monitoring a soil’s health.
What Do Earthworms Do to the Soil?
Bury and shred decaying plants. Plant and crop residue are gradually buried by worm castings deposited on the surface and as earthworms pull food from the surface into their burrows.
Mix and improve soil. As the earthworms consume organic matter and mineral particles, earthworms poop out their waste in the form of casts. Earthworms can move large amounts of soil from the lower strata to the surface and also carry organic matter down into deeper soil layers over periods of time. A big percentage of soil eventually passes through the guts of earthworms, and it is estimated that they can turn over the top six inches of soil in 10 to 20 years.
Improve water-holding capacity. By breaking apart organic matter as they crawl and eat, earthworms loosen the soil and increase the water-holding capacity.
Loosen the soil and make it porous. Earthworms enhance porosity as they move through the soil. Some species make permanent tunnels deep into the soil. These tunnels can last long after the earthworm has died, and can help with soil drainage, particularly under heavy rainfall. At the same time, the tunnels minimize surface water erosion. The horizontal burrowing of other species in the top several inches of soil increases overall drainage as they loosen the soil.
Provide channels for root growth. The tunnels made by the burrowing earthworms are lined with readily available nutrients from their castings, which makes it easier for roots to penetrate deep into the soil.
Increase the soil’s microbial diversity. Earthworms get their nutrition from microorganisms like bacteria and fungi, but there are more microorganisms are present in worm castings (worm poop) than in the organic matter that they consume. As organic matter passes through their intestines, it is fragmented and inoculated with microorganisms. Increased microbial activity facilitates the cycling of nutrients from organic matter and their conversion into forms readily taken up by plants.
Red wigglers are commonly associated with compost, as they are the most likely to appear in compost heaps and are the ones used most often for vermicomposting (composting with worms). They are faster than any other organism at the job.
Increasing Earthworms in Garden Soil
Obviously, you could purchase worms (they are sold by the pound in many garden stores) and just manually add them to the garden. This will work for the short term, but will not be very beneficial since worms are needed all season.
Encouraging worms naturally is the best way. It’s a case of “if you build it, they will come” as in the better your soil for worm habitat, the more worms that will live in it. You don’t need to add worms, just encourage them to be there and they’ll show up on their own and improve your soil structure and make it easier for your plants to grow.
First, worms love organically-rich soil with a lot of nutrients and a neutral pH level. Start by doing basic tests on your soil (if you can) or just add a lot of organic matter to it. Till it in well and then add more on top, either as growing material (cover crops like clover or buckwheat) or as mulch (clipped grass, leaves, straw, and other quality mulches work best). Occasionally add light water and poke the soil with a compost form (do not turn it).
After a few weeks, perhaps two months, dig a cubic foot of soil and examine how many worms are in it. You should notice a marked increase. By the end of the season, you should not only have a lot of worms per foot, but also have very rich, healthy soil with more organic matter thanks to the hard work of those earthworms.
Once the soil is healthy, just maintain it and the worms will stay, no matter what you’re growing in it. An added bonus is that the great soil will not only grow huge yields, but by periodically checking the worms in it, you can tell if something might be going wrong when the worms start leaving.
Believe it or not, earthworms generate literally tons of casts per acre each year, dramatically altering soil structure under the ground.
Maintaining a Healthy Environment for Earthworms in the Soil
Worms, as said earlier, love nutrient-rich, healthy soil. If you keep adding compost and mulches regularly, you’ll always have great soil. The worms will become part of its ecosystem.
Want to learn more about increasing earthworms in your garden soil?
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