Tuesday, June 28, 2011

Who-dun-it: Case of the Toppling Potato Plant

Who-dun-it?
Photo: Susan Levi-Goerlich




Susan Levi-Goerlich wasn’t a happy gardener. Something was eating her snap peas about three inches above the ground—and then chard leaves began to go missing.

Hmm, she thought, mice. Then—both on the same day—a beet and a potato plant fell over. Susan, who gardens at the West Side Community Garden of the Columbia Gardeners, Inc., checked the potato plant that had fallen over and discovered that the young potatoes had been eaten underground.

Voles, also known as meadow or field mice, she concluded. They’re cute, stocky, short-tailed mice-like creatures that have a sweet tooth—especially for sweet potatoes—and, as Susan found out, for potatoes and other root vegetables and some above-ground veggies too.


Voles love potatoes
Photo: Susan Levi-Goerlich
“I pulled up all four varieties of my potatoes, including Yukon Gold and Red Pontiac varieties,” she said. “The voles had eaten all the largest potatoes, and they seemed to favor my expensive French fingerlings.”

Susan confirmed her suspicion about voles by emailing a query and a photograph of damaged potatoes to the University of Maryland Extension’s Home and Garden Information Center, which recommended baited snap traps as a remedy.

Susan put out some humane traps—live traps—because she doesn’t want to endanger birds that might be attracted to baited snap traps.

“I’ve already caught two voles,” Susan explained when I met her at her plot early Monday morning. “One expired in the trap before I found it. The other I took for a long ride in the country and released it in a meadow far from any house, farm, or garden.”

Susan likes the larger traps because she thinks voles are more likely to enter them. She showed me how she baits them with a peanut-butter and rolled oats mix and then set them into her garden near her beets.

Susan baits a trap
That was Monday morning at 7:30. Just before 10:00 she emailed me: “Caught 2 more right after you left! Youngsters. And saw two more right near or in my compost bin. I’ve got to get more traps.”

Susan probably has a grand battle on her hands. If she’s caught four voles in her plot and seen more, how many more live in the many plots at West Side Community Garden, which the voles probably call West Side Five-Star Restaurant, with plenty of hiding places and a couple of acres of soft gardening soil in which to burrow.

Baited humane traps? Snap traps? Where are all the hawks, foxes, and blacksnakes when you really need them to eat voles for lunch?

For small areas, some gardeners give up on traps and surround vole-vulnerable crops with hardware cloth sunk six-inches into the ground. At their demonstration garden at the Agricultural Farm History Park in Derwood, Montgomery County Master Gardeners show how it’s done by digging a trench around a sweet potato bed and installing a barrier of 24-inch hardware cloth.

Traps near Susan's beets
Erica Smith, vegetable garden leader, explained how the Master Gardeners build the barrier: “Basically the hardware cloth is shaped into an oval (because that's easiest; could be another shape) and set into a trench dug about six inches below outside soil level. Inside, the soil is piled up about 8 inches or more before the plants are set in. The fence is 2 feet high altogether so extends 1 1/2 feet above ground and 6 to 10 inches above the planting level. It does a great job keeping out the voles and other critters. Sometimes the plants do grow through it underground and those sweet potatoes get chewed on.”

To access a blog posting about the demo garden that includes a photo of the trench around a sweet potato bed, CLICK HERE. To see a posting that includes a photo of the completed barrier, CLICK HERE. To access information about the demonstration garden, including hours and a map, CLICK HERE.

To learn more about voles and what they look like, CLICK HERE to access the University of Maryland Extension’s Fact Sheet 654, “Reducing Vole Damage to Plants in Landscapes, Orchards, and Nurseries.”

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