REGIONAL— Ask an old-time gardener in the North Country and you’ll usually hear advice against planting the sensitive plants, like tomatoes and squash, too early.

“June 10 seems to be the cutoff date,” said Gary Rantala, a longtime horticulturalist who lives in Embarrass.

And as temperatures dropped into the upper-20s and low-30s early Wednesday morning, June 8, that bit of folk wisdom held true for the second year in a row across much of northern St. Louis County. That’s when frost hit much of the area, with hard freezes reported in some locations. Open or low-lying areas, like Embarrass and Brimson, reported an overnight low of 28 degrees, while the Hibbing airport checked in at 29 degrees. Many areas saw temperatures at or below the freezing mark.

“It definitely wasn’t a surprise,” said Rantala. “It seems like it happens every few years.” The National Weather Service had issued a frost advisory for Wednesday morning, but the weather office hadn’t predicted a hard freeze.

Over in Greaney, near the Littlefork River, temperatures also dipped below freezing. “We had 29 degrees,” said Leah Rogne, who noted that she and her husband Fred Schumacher had taken protective measures in their garden, covering sensitive plants with blankets, tarps, and ice cream buckets. “The garden is fine,” she said, despite the cold.

Rantala said he and his wife Sharon saw frost at their house as well, but they weren’t positive about the overnight low. He notes that they live at the top of a hill, which does help to drain the cold temperatures away. “That makes a big difference,” he said.

Even so, he took no chances, moving sensitive plants— which these days he grows mostly in containers— inside.

Jack LaMar, the new owner of the Early Frost Farms and Greenhouse in Embarrass, had noticed the frost advisory and had been warning customers who came in on Tuesday. But he forgot to cover his own garden, and took losses as a result. “The cucumbers were very wilty. It was a killing frost for sure.”

While many garden plants, such as broccoli, cabbage, carrots, and peas are quite frost hardy, others can be damaged even as temperatures approach freezing. “With any of the melon crops, anything below 40 degrees will stunt them for a few hours or even days,” said Rantala. Other common garden plants, like tomatoes or eggplant, are sensitive to cold as well. Rantala said there’s a rule of thumb that can help gardeners predict which plants are sensitive, and which can tolerate a little frost. “If you eat part of the plant itself [such as leaves, heads, or roots], those are considered cool weather plants. If what you eat comes from a flower, that’s considered a warm weather plant. About the only exception would be peas.”

With gardening increasingly popular these days, many gardeners in the North Country are turning to more advanced methods of not only protecting plants from late frosts, but also increasing the amount of heat available to plants. Farmers refer to the need for heat as “growing degree days,” and for many crops, it takes a certain number to bring plants or their fruits to maturity. Methods such as greenhouses, hoop houses, row covers, or water teepees, can all help to raise temperatures around plants, even on typically cool June days here in the North Country, and increase growth rates and speed ripening of plants.

Janna Goerdt, who operates Fat Chicken Farm in Pike Township, has taken many of those methods to heart. While the weather so far this spring has left her with little growing in her outdoor beds, underneath her big hoop house, or “high tunnel,” it’s full-on summer and she’s made her first deliveries this week to customers of her Community Supported Agriculture, or CSA, operation. She’s also planning to have more early season produce, like lettuce, herbs, and a variety of other salad greens for sale when the Tower Farmers Market kicks off its summer season this Friday, June 10, from 4-6 p.m.