Worms are lowly creatures that are either welcomed or hated in the garden.
According to an article in the Canadian Geographic Magazine, worms native to Canada, with the exception of the West Coast, disappeared with the last ice age.
Worms as we know them either wiggled their way north from areas that were not touched by glaciers or were imported by settlers in soil.
Worms have been long recognized for the good they do in the soil: aerate, cultivate and fertilize.
They move through the soil, taking in soil at one end and expelling it at the other. In doing so, they create open tunnels or burrows that loosen the soil, which in turn speeds up root growth.
Tunnels increase the amount of air within the soil and enable moisture to move through the soil, increasing soil’s ability to hold moisture.
The most noticeable tunnels are the ones that breach the surface of the soil, leaving their castings on top to form lumps.
Continued breaching of the soil surface by worms will result in the ground becoming rough and bumpy.
The large worms that inhabit Central Alberta, known locally as “dew worms,” are disliked by anyone trying to achieve a smooth lawn.
Darwin, who spent over 40 years studying worms, found them to be nature’s cultivators.
He estimated that it would take worms 10 to 20 years to turn the top six inches (15 cm) of soil if it wasn’t disturbed.
The length of time varies due the soil composition of the soil, as well as the number of worms present.
Today, the concept is used in no till gardening. To be successful, the soil must contain enough organic matter to attract worms.
Worms devour dead material, plant or animal, turning it into nutrient-rich castings that are in turn used by the plants grow.
A worm can eat enough material to produce its weight in castings every 24 hours.
These sightless creatures pull dead organic material into their tunnels, enriching the layers below the surface.
Worm castings contain many mirco-organisms that free nitrogen, making it available for the plant roots. Worm castings are harvested and sold as organic fertilizer.
Worms are hermaphrodites, containing both male and female genital, but they can’t reproduce on their own.
They come to the surface to mate and take the cocoon back below the surface. The new batch of worms hatch and the cycle continues. Worms reproduce rapidly, gradually spreading into the surrounding areas.
Exterminating worms, regardless of the variety, is impractical and not logical as they do improve the soil.
Minimizing the piles of casting left on the lawn surface is an option and can be completed in three easy steps. Start by sweeping the lawn with a power brush.
This will dislodge any loose castings. Next go over the lawn with a heavy roller, which should flatten any remaining lumps. The final step is to aerate the lawn by removing plugs of soil to reduce the soil compaction that took place when the lawn was rolled.
There are chemical available to kill worms. The worm must be on the surface of the soil when the chemical is applied for it to be effective.
Once sprayed, the worms die and need to be removed before they are consumed by birds. Birds that eat the dead or dying worms are also poisoned.
Gathering dew worms for fishing bait is big business in southern Ontario.
The worms are picked off the ground at night with the use of head lamps, packaged, stored and sold throughout Canada and the United States.
Linda Tomlinson is a horticulturalist who lives near Rocky Mountain House. She can be reached at www.igardencanada.com or your_garden@hotmail.com.