NDSU urges growers to keep grain cool and dry during summer


“Cold or cool grain has been safely stored through the summer for many years,” notes Ken Hellevang, an Extension agricultural engineer. “Keeping the grain as cool as possible should be the goal of spring and summer grain storage.”

Allowing grain to warm to average outdoor air temperatures during the summer can lead to insect infestations and mold growth. The optimum grain temperature for insect activity is approximately 70 to 90 degrees. Reducing grain temperatures below 70 degrees will lessen insect reproduction and activity, and lowering grain temperatures below 60 degrees will greatly reduce insect activity.

Hellevang warns that using aeration could warm the grain, which may increase the moisture content of the grain slightly. Aeration fans should be covered to prevent wind and a natural chimney effect from warming the grain. Wind blowing into uncovered fans or ducts will move air through the grain in a way that is similar to operating an aeration fan.

One challenge to keeping the grain cool during the summer is that solar energy on the bin roof heats the air above the grain. Convection currents in the grain flow up along the bin wall and down into the grain near the top middle of the bin, drawing this heated air into the grain. Ventilating the space between the grain and the bin roof can reduce the amount that the grain near the top of the bin is warmed.


Cool grain in the upper portion of the bin by operating the aeration fan about every three weeks during a cool early morning. Using positive-pressure aeration to push air up through the grain enables the cool grain in the bottom of the bin to cool the air, which then cools the grain near the top of the bin.





Mold growth and insect infestations occur rapidly at summer temperatures, so stored grain should be checked every two weeks. A situation with only a few insects can turn into a major infestation in less than a month. Using insect traps or placing grain samples on white material helps you look for insects.

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