I gotta have more worms!

Hands holding worms in dirt.
Photo credit: EESC slide collection
Q:

Where can I find information on adding worms to soil that has none? Thanks.

- Multnomah County, OR
A:

it’s useful to know that it would be extremely unlikely for soil to be void of worms. More likely the population is low enough that you don’t see any. Various factors affect worms, and whether or not they are numerous. For instance, worms don’t survive if soil is dry or flooded. The preferred moisture content is the same as is suitable for garden plants.

One method is to create a particularly suitable site so that the existing worms will feed and multiply. To accomplish that, mix in 4 inches of compost into the soil each season you plant. (Split the compost addition into two stages: Mix in 2 inches, then mix in 2 inches more.)

You can also inoculate your soil with a “starter” population of worms. As is stated in the final line of this resource “…dig a large spade-full of soil from an area with visible worm numbers and bury this soil in the area where worms are needed.”

Whatever method you use to increase the number of worms in your soil, know that you must continue to add organic compost to the soil each season to sustain the worm population.      

Note from Gail Langellotto, Statewide Master Gardener Coordinator:

Worms are not naturally in Central Oregon/high desert soils. Gardeners in those areas need to purchase and care for their worms as if they were pets (feeding, watering, providing bedding). 

Jean R. Natter
Master Gardener Diagnostician
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