Jane's Garden 3/2/14: Moles actually a benefit to gardens

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Critters control insects, naturally aerate soil

Recently a reader emailed to ask how to remove pesky moles from the garden. Their telltale raised mounds, which indicate feeding tunnels, were creating quite a mess in her yard.

The Eastern Mole, Scalopus aquaticus, is found throughout Florida except in the Keys. It is an insect-eating mammal in the Insectivora class, which includes shrews and hedgehogs. The class has four families, with 442 species globally. Star-nosed moles are found in northeastern Florida in the wetlands around the Okefenokee Swamp.

Moles are part of the natural environment and are beneficial in the garden, because they eat about 60 percent of their weight each day in insects and earthworms. They loosen and aerate the soil while searching for food.

The feeding tunnels just under the surface are dug in early evenings and mornings when the moles leave their deeper living chambers to forage. After they eat the insects, they burrow further in search of more, so they rarely reuse the same feeding tunnels for long. An Eastern Mole can dig about 18 feet an hour, and up to 150 feet in a single day.

Eastern Moles are about 5.5 inches long with a short, 1 to 1 1/2 inch tail. Their velvety, dark gray fur stands straight up, enabling them to burrow forwards and backwards. It does not gather dirt as the cute little animal forages. They prefer sandy, well-drained soil and shun stony or rocky areas. The soil must be able to maintain the deeper living chambers without caving in.

Surface feeding tunnels will collapse in a heavy rain or if stomped or driven on. While annoying, these tunnels do no lasting damage. Moles occasionally displace bulbs and could damage grass roots while searching for insects, and unearthed plants could dry out and die.

I have many resident moles in my yard. They are attracted to the earthworms in the humus-rich amended soil I have created to grow a fire-break lawn encircling my home, fruit trees, veggies and ornamental flowering plants. The back half of the yard is largely original sandhill scrub with indigenous vegetation. I find just as many feeding tunnels there as in the amended areas. Moles are beneficial carnivores, while the alien nine-banded armadillo and feral pigs can devastate a garden overnight.

Moles are solitary creatures that breed once a year in January or February locally. Nest chambers are 12 to 20 feet below ground, 4 to 6 inches in diameter and lined with dry grass and leaves. After about 45 days’ gestation, 2 to 5 live babies are born. The mother nurses them for about 4 to 5 weeks until the young are able to forage on their own. Moles are prey food for foxes, snakes, skunks, hawks, owls and free-ranging cats and dogs. Terriers in particular like to hunt them. Any cornered wildlife tries to defend itself and could bite attackers. Cats and dogs are so big and quick, the mole doesn’t have much chance to bite them.

There are traps sold in farm stores that may kill one mole at a time. The vacated territory will soon be claimed by another mole. Chemical control of insect pests would require repeated applications of poisons to your garden that eventually flush into the aquifer for everyone to drink. Soil drenches of emulsified repellants last longer in amended loam and clay soils, but rains wash these castor and ricinus oils away, so they must be reapplied often.

Mole tunnels are seen on roadsides where traffic vibration does not bother them. While there has been no scientific study on the solar-powered sonic vibrators sold in hardware stores for about $20, I have found them useful in my garden. Make a 10-foot-deep, 1.5-inch-diameter hole with a piece of pipe in full sun and angled slightly toward the south. Insert the battery tube with the plastic solar panel at soil level. It makes a high-pitched sound that travels well through the soil but is barely audible to humans. The resident moles will have their daytime sleep disturbed and initially tunnel to the source to investigate. After a few days, they leave the immediate area to sleep and forage further from the annoying sound. The plastic lens breaks down after a year of sun exposure, and can be renewed with car headlight cleaner.

Jane Weber is a professional gardener and consultant. Semi-retired, she grows thousands of native plants. Visitors are welcome to her Dunnellon, Marion County, garden. For an appointment, call 352-249-6899 or contact JWeber12385@gmail.com.