At one point, farmer Kate Hall resorted to setting up security cameras. By then she had a pretty good idea about what was decimating entire trays of her tender young microgreens – nearly $1,200 worth in one night.

But she wanted to know how the mice were getting into her recently insulated Northport grow room; if she knew their access point, maybe she could seal it. On the tapes, she could see the mice, slipping in through tiny cracks in the farm’s foundation. She filled in the cracks. But some mice still get in, settling in for midnight suppers of Graze Maine’s specialty crops like beautiful baby spinach, just germinated sunflower seeds and shiso, the last of which is a very expensive seed for her. “This is literally this apocalyptic problem that we are all facing this time of year,” Hall said.

She was not the only farmer to use the word apocalyptic. As the chilly North grinds slowly toward spring, Maine farmers are united in playing what Hall jokingly refers to as an adult board game: eradicating mice, voles and rats from greenhouses and grow rooms.

It’s a relatively new game for Dominic Pascarelli at Two Farmers Farm in Scarborough, who wrote an email in the middle of a “doozy” of a week to say that rodents had not generally been much of an issue in the past. But this year, a cost-saving measure led to something of an invasion.

“If you put hay bales around a seedling greenhouse in an attempt to save on heating costs, be prepared to set and creatively bait many mousetraps for deer mice and meadow voles,” Pascarelli said.

Those are the common pests in Maine greenhouses, according to Griffin Dill, an integrated pest management professional with the University of Maine’s Cooperative Extension, along with the white-footed mouse and an occasional chipmunk. It’s a “relatively significant issue,” Dill said. One pre-emptive measure is keeping the grass around greenhouses carefully mowed; tall grass leads to much higher rodent populations, Dill said. It provides cover for covert rodent activity. “They feel a little safer and can spend some time chewing and gnawing on the parts of the greenhouse to get inside,” Dill said.

Such pests aren’t just an annoyance, either. Rodents can cost a farmer dearly, not just in the price of seeds, but in time, perhaps the most precious commodity.

“They can wipe out 50 plants in a night, and it’s not like you can just back up time and start them over again,” said Andrew Mefferd, a farmer in Cornville who is the editor of Growing for Market Magazine and an author of books about farming.

Farmers trade tips on social media – Pascarelli has had success baiting traps with a pink Starburst (yes, the candy). They lend each other cats (which aren’t a perfect solution), and they study the ways of farmer gurus like Eliot Coleman, who doesn’t bother with bait but favors luring them into a box perfectly sized and intriguing for a vole or a mouse, furnished with a set trap.

“Eliot being Eliot, I think he builds special little wooden boxes, with doors on either side,” said Mefferd, who uses just a cardboard box. And a lot of traps are set with peanut butter.

“It seems like everything in the world likes peanut butter,” Mefferd said.

Dill agrees that peanut butter is generally a safe bet. He also recommends attaching a tiny bit of string to the mousetrap-baiting mechanism, and putting peanut butter on that.

“Because mice are surprisingly good at removing bait without setting it off,” Dill said. “This way they will work on the bait, start to chew on the string, and that will set it off.”

As for the Starburst trick?

“This is a first for me,” Dill said, “although I have heard of using sugary substances.”

Kelsey Herrington, Pascarelli’s partner at Two Farmers Farm, said they stumbled on the pink Starburst trick.

“We know a farmer in New York who said he always catches mice with bubble gum,” she said. “I went to the drug store and I could not find bubble gum, so I got Starbursts. Every so often there is like the one mouse who is undefeatable. Lately it seems like the pink Starbursts work on that mouse.”

She doesn’t use the whole candy, just a chunk of it, and softens it a little with her hands before sticking it on.

Peanut butter is often the preferred bait for mice. “It seems like everything in the world likes peanut butter,” says Andrew Mefferd. Hong Vo/Shutterstock.com

“It makes sense to an extent,” Dill said. “It is kind of chewy and it may keep them around longer. I can kind of see the rationale.”

Dill recommends bait of apples for voles and oats and seed for mice. And of course, peanut butter.

PASS ON THE PEANUT BUTTER

The mice who visit Kate Hall’s Graze Farm, will pass on the peanut butter. They also ignore the broccoli and kale. They’d rather have her edible flowers, like borage, or herbs like shiso, also known as red perilla. A pea shoot seed planted just five or six days ago? Delectable.

“And then it is like, wow, it is gone. They just wait until it is at that sweet spot,” Hall said.

Hall plants 2,000 seeds at a time. This is serious. “Right now is crunch time because we are seven weeks into our seedlings.” She plants extra seeds. And she struggles to find something as alluring to the mice as a tray full of borage.

“The people at the hardware store are like, ‘You can’t catch it with peanut butter? What is wrong with you?’ ”

She’s put out traps, but the victory of killing a mouse is marred by the visual. “You have these beautiful greens growing and you see a dead mouse very close to them? You can’t sell it. That is disgusting.”

One farmer who favors the Snap-E mousetraps declined to comment for precisely this reason, fearing it would be negative advertising. But it’s no one’s fault. The enticement of a greenhouse in early spring is obvious to Christa Bahner of Bahner Farm in Belmont. “In March, it is like everything is frozen,” Bahner said. “And there is a warm room full of food.”

In mid-March she shared a photo of 10 traps on Instagram, lined up neatly, with the caption “setting up to do battle in the seedling greenhouse tonight.” Her fellow farmers immediately responded with laments about how bad a year it is for rodents (rats are plaguing some houses). Hall, just down the road from Bahner Farm, took some comfort from that. Misery does love company.

“I don’t ever want that for anybody,” Hall said. “But in a situation this absurd, it almost brings me comfort.”

TWO CATS IN THE HOUSE

The most obvious solution would seem to be cats. At Bahner Farm, they added a second cat. Princess Leia, a small female, was doing yeoman’s work already, but Curtis, a barn cat from the Coastal Human Society in Brunswick, has picked up the pace.

“That pretty much took care of it,” Bahner said. They still put out traps – the cats prowl the outside of the greenhouse only, “picking thing off as they come in and out of the field.” Mowing the area outside the greenhouse in true spring also limits the comfort level of mice trying to sneak in and out of the greenhouse. She also takes measures throughout the season like trellising sweet peppers (another mouse favorite) to keep them out of mouse eye level.

Why not just bring the cats into the greenhouse? Well, they’re diggers.

And sun worshippers, not to be trusted with seedlings.

“We try to keep them out of our propagation area,” said Mefferd. “Because they like to walk across our flats and sometimes lie down on them because they’re warm.”

Hall has considered borrowing cats from a farm close by. “But I really don’t need one more thing to take care of.”

BRING IN THE GUAVA

Once she stopped trying to kill the mice, Hall shifted her strategies. She tried moving some trays of shiso to an upstairs bedroom (helpful). She’s transitioning to metal shelving, which apparently the mice are less interested in crawling up. Duct tape on the legs of shelving helped a bit. She’s tried a byzantine homegrown non-lethal trick involving a rolling pin, a bucket with tasty grain at the bottom and a ramp.

“I have literally tried it all,” Hall said. “It’s like a mind game.”

The bucket trick means disposing of the (live) mice elsewhere, a few blocks away, but she recognizes that has a built-in problem. “They might make their way back.”

So Hall is trying a new method. She called up Greener Grounds Landscaping, an earth-friendly lawn and garden care business in Owl’s Head, run by Evan Frace. They’ll be coming five times in the season to spray around the perimeter of her house, with some mixture of apparently unappealing-to-rodents scents and flavors that include guava and peppermint. She’s hopeful. But well aware there is one thing that she can’t change.

“Unfortunately, the root of the problem is what we do,” Hall said.

Mary Pols can be contacted at 791-6456 or at:

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