Myth Debunked! Scorpions & Wood Chips

Shedding the “Black”Light on Wood Chip Mulch: Are Scorpions an Issue?
A Scientific Study Investigates.

Conclusion: Scorpions are NOT “Attracted” to Wood Chips!

The 2019-2020 freshman students of Sky Islands High School in Tucson and their enthusiastic teacher Allie Silber conducted a study to get to the bottom of a question hovering around in the landscape: “Are scorpions attracted to wood chip mulch?”

Mulch is extremely beneficial to soil and plant health. It reduces water loss, insulates the soil from extreme temperatures (summer soils are 10-30F cooler beneath mulch!), controls erosion, reduces weeds, promotes beneficial microbes, and produces a beautiful aesthetic appearance.
Plus, organic/wood mulch is a renewable, recycled product.

Rock mulch or DG, on the other hand, provides only erosion control (and none of the other benefits). Also, it is a mined/nonrenewable material.

Despite the proven benefits of wood chips, some homeowners are leery of using wood/organic mulch for fear of attracting scorpions. The study conducted by the students (under the oversight of Field Studies teacher Allie Silber and industry expert Emily Rockey) proved that scorpions are not simply attracted to wood chips, but instead seek the cover and protection of covered, narrow spaces (like those the wood shingles provided). Blacklights were used to locate the scorpions, which glow under the special light.

The poster presented at the 2019 SER (Society for Ecological Restoration) Conference held at the University of Arizona. The students did a fantastic job interpreting their findings.

Each terrarium was divided into 4 treatments: Control (dirt), Wood Chips, Rock, Wood Shingles.

Four identical terrariums, below, were created with each of the 4 treatments, plus 2 live bark scorpions within each. Scorpions’ locations were recorded each week for six weeks to determine preferred terrain/medium.

Sky Islands High School prepared a flyer in 2019 sharing the results of their findings (below).

We’d like to thank the following people for their help and support on this project: