MINNEAPOLIS, March 21, 2012 (AP) — Mike Bergeron started sowing wheat on his farm in northwestern Minnesota on St. Patrick's Day. One week earlier, he was towing two of his daughters on a sled behind his snowmobile.

Bergeron and his business partner Jon Ross are among at least a few farmers in the Upper Midwest taking advantage of an unusually mild and dry winter to start planting spring wheat in mid-March. While there could still be a bad frost, they're taking a calculated risk that the early start will let them reap a bigger crop this summer.

"It's crazy, isn't it?" Bergeron said with a laugh on Tuesday, the official first day of spring.

Experts said that while it's rare for farmers in the Upper Midwest to plant this early, it's not crazy.

"We're still on the early side, but that's the key to having a good wheat crop — it's planting early," said Doug Holen, a University of Minnesota Extension educator based in Morris. He said he knows of wheat growers in other parts of Minnesota who also have started planting.

Wheat yields tend to be better in cooler weather partly because wheat makes more efficient use of soil moisture the earlier it gets planted. Wheat and other small grains such as barley and oats also aren't as susceptible to frost damage as corn and soybeans.

Those farmers are sitting tight because planting before mid-April doesn't normally benefit their crops, said Darrell Good, an agricultural economist at the University of Illinois. The key with corn is avoiding late frosts and getting enough warm days over the season, while soybeans have a shorter growing season there's no urgency to get them planted early, he said.

While Kansas is often the country's top wheat producing state, it grows winter wheat that's planted in the fall because its summers are too hot and dry. North Dakota, Montana and Minnesota typically are among the spring wheat leaders.

Joel Ransom, an extension agronomist at North Dakota State University in Fargo, said while he's hearing that some wheat growers there are getting anxious and might be about to start planting, he hasn't actually seen anyone doing it or spoken with anyone who will soon. While North Dakota also has had a mild, dry winter, the soil there is wetter than in Minnesota and needs to dry a bit more, he said.

The ground is also still a little too wet in Montana, said Lola Raska, executive vice president of the Montana Grain Growers Association. She said she hasn't heard of any wheat being planted there, but some farmers are likely to start sowing barley soon. "As soon as the ground is warm they'll be out there," she said.

Still, St. Patrick's Day planting is unusual. Ross' father, who's 84 and started their farm near Fisher, has planted at the end of March but never as early as March 17, Bergeron said. Bergeron himself had never planted earlier than April 7.

But the men checked with their crop insurance agent and a small-grains specialist, and persuaded skeptics at their local co-op elevator to come out and apply fertilizer last Saturday. Then the rush to plant was on. Bergeron said they have planted 450 acres of wheat and hope by Thursday to be halfway to their goal of 1,200 acres.

Eventually, they'll turn their attention to soybeans, sugar beets and sunflowers for the rest of their 3,800 acres.

A key factor in their decision to plant early was that it's been unusually dry across the Upper Midwest since late last summer. Snow cover was minimal over the winter.

Bergeron said there were only 3 to 4 inches of snow on the ground earlier this month when he was giving his daughters rides behind his snowmobile, and it all vanished quickly with the onset of record warm temperatures in the 70s.

Fearing the drought might persist into the summer, and with no freezing weather in the medium-term forecast, Bergeron and Ross decided their odds were better with an early start. Replanting if there's a freeze would cost about $12,000, but they're hoping Mother Nature rewards their risk with at least a normal yield for them, perhaps 70 bushels per acre, despite the dry weather.

"Mother Nature always has its own mind, though," Bergeron acknowledged with a laugh.