by Nicole Luhr - Extension Educator
May is a busy month on Nebraska farms. Planters are rolling, weeds are emerging, and attention is turning to the growing season. But while you’re focused on the field, it’s important not to forget what’s still in the bin.
As temperatures warm across Nebraska, stored grain requires closer management than ever. Grain that made it safely through winter can deteriorate quickly in the spring if it’s not monitored.
Let’s start with moisture. For corn stored into late spring or early summer, moisture should be 13 to 14 percent or lower. Corn stored above that level is at greater risk as bins warm. For soybeans, moisture should be 11 to 12 percent for continued storage. Soybeans are especially sensitive to quality loss once temperatures rise.
Now let’s talk about temperature. Over winter, grain was likely cooled to 30 to 35 degrees Fahrenheit. As we move into May, outside air temperatures climb, and warming grain creates moisture movement inside the bin. That can lead to condensation, crusting, and spoilage—often near the top or along bin walls.
Grain should be kept as cool as possible for as long as possible. In early May, aeration can still be used during cool nighttime or early morning hours to hold grain temperatures below 40 to 45 degrees. Once nighttime temperatures stay warm, fan use should stop to avoid warming the grain.
During May, bin checks should increase to every one to two weeks. Look for surface crusting, wet spots, insects, or changes in odor. Musty or sour smells can be an early warning sign of spoilage.
Insects are a major concern this time of year. Stored grain insects become active once grain temperatures climb above 50 degrees. If populations go unchecked in May, they can explode by summer. Early detection keeps management options affordable and effective.
Also pay attention to roof leaks, vents, and seals. May storms can introduce moisture that quickly damages grain. Make sure fans, roofs, and access covers are in good condition.
And remember—safety always comes first. Never enter a grain bin alone, and never walk on crusted or bridged grain.
Conditions that cause spoilage also create extremely dangerous situations inside the bin. Many inspections can be done safely from outside using proper tools.