It took a while for me to get used to the idea of winter wheat. I grew up in the farm country of Iowa and Illinois. We didn't farm, but most of our relatives did, and like most Midwesterners, we kept an ambitious garden, canned our tomatoes, froze our green beans, and put up a special taco sauce that would etch the inside of a Mason jar.

From the time I was six or seven, I was involved in the primal rhythm of the agricultural year--break ground in the spring, cultivate (which is to say, hoe weeds) all summer, harvest in the fall. The pattern was no different for the full-time farmers around us. The fields were bare black dirt in May, emerald green in July, tan and ripe in October.

After I finished college, the vagaries of the job market led me to southern Kansas. With the advent of center-pivot irrigation, Kansas farmers had their choice of several crops--corn, milo, sunflowers--but this was still the middle of the Wheat Belt, and dry-land wheat was still king.

Winter wheat, which was the confusing part. The fields were plowed and planted in September; they greened up like suburban lawns with the moisture of early winter, then lay under the snow until March. By May, the fields were waist high in grain, and the harvest was in July. Backwards.

In a part of the world where summer drought is a way of life, backwards isn't necessarily a bad thing. A plant that can sprout in the fall gets a running start the following spring with the moisture from snowmelt and first rains of the season. It shades out annual weeds before they get started and ripens before the worst of the insect pests and diseases have a chance to attack.

The trick, of course, is to avoid being frozen solid during the winter. Plants vary in their ability to withstand cold. Among the small grains, rye tends to be most tolerant of low temperatures; wheat tends to be most vulnerable.

The first strains of wheat that could make it through a prairie winter came to the New World with Moravian farmers from Russia who settled in Kansas, bringing with them a variety that not only survived the winter cold but needed the chill in order to set seed the following spring.

Kansas provided a fortunate combination of relatively mild winters and enough snow to insulate the young plants, protecting them from the occasional arctic front. Winter wheat quickly became an agricultural staple on the central plains.

Still, there were limits to the cold winter wheat could take. On the northern plains, where winter temperatures could drop past 50 below and the wind could scour a field of its insulating snow, farmers stuck with spring wheat and a little winter rye.

In 1919, Arthur Buller, a botany professor at the University of Manitoba, explained the difficulties facing winter wheat in southern Canada: