Jumping Worms: A New Soil Threat Heading Our Way

A new invasive pest is quietly working its way north into the Pacific Northwest, and it’s not one we can ignore. “Jumping worms” (Amynthas species), now established in parts of Oregon as far north as the Washington State border, are already causing serious concern for gardeners, farmers, and natural ecosystems.

If you haven’t seen them yet, it’s likely only a matter of time.

👉 Watch the OPB feature here:https://www.opb.org/article/2026/06/12/jumping-worms-oregon-soil-invasive-species/

Image from btlt.org

What makes jumping worms so different?

At first glance, they look like any other earthworm. But unlike beneficial worms that improve soil, jumping worms do the opposite.

They live in the top layer of soil and rapidly consume leaf litter, compost, and organic matter—the very materials we rely on to build healthy garden soil. [opb.org], [extension....nstate.edu]

As they feed, they leave behind a distinctive soil texture often described as dry, loose, and similar to coffee grounds.This isn’t just a cosmetic issue—it signals a major breakdown in soil structure. [opb.org]

Why this is a problem for gardeners

Once jumping worms establish themselves, they can trigger a cascade of soil issues:

• Loss of organic matter: They strip away mulch and leaf litter that protect and feed the soil. [extension....nstate.edu]

• Poor moisture retention: Their castings repel water rather than absorb it, leaving soil dry and drought-prone. [extension....nstate.edu]

• Weakened soil structure: Soil becomes crumbly and unstable, making it harder for roots to anchor and access nutrients. [opb.org]

• Reduced plant growth: Shallow-rooted crops in particular may struggle or fail. [yahoo.com]

• Higher disease risk: Changes in soil biology can increase susceptibility to soilborne issues. [corvallisa...vocate.com]

In short, they turn fertile soil into something far less capable of supporting healthy crops.

What you can do to protect and rebuild your soil

There is currently no simple, reliable way to eradicate jumping worms once they are established. The focus needs to be on limiting their spread and adapting soil management practices.

Here are practical steps you can take:

1. Be cautious with soil and compost

• Avoid bringing in bulk soil, compost, or mulch from unknown sources

• Inspect plants and root balls carefully before planting

• Use trusted suppliers or start from seed where possible

Jumping worms often spread through contaminated soil and plant material. [uvm.edu]

2. Rebuild organic matter—carefully and consistently

Even though worms consume organic material quickly, continuing to add it is essential:

• Apply finished compost in smaller, more frequent applications

• Use well-aged materials rather than fresh mulch layers

• Consider cover crops to help protect and rebuild soil structure

3. Protect soil moisture

Because affected soil sheds water:

• Water more deeply but less frequently

• Add organic amendments that improve water retention, such as composted manure

• Consider shade cover or living mulch to reduce evaporation

4. Minimize disturbance and spread

• Clean tools, boots, and equipment between sites

• Avoid moving soil around your garden unnecessarily

• Do not share plants or compost from infested areas

5. Adapt planting strategies

• Focus on plants with deeper root systems that can better tolerate shifting soil conditions

• Monitor crops closely and be ready to amend planting areas with improved soil mixes

Final thoughts

Jumping worms are on their way from down south, and they’re likely to become part of gardening in the Pacific Northwest. While not here quite yet, it's always best to be prepared.

The key will be good soil stewardship, vigilance, and adapting how we manage organic matter and moisture.

As always, the better we understand what’s happening beneath our feet, the better we can respond above ground.