By Jim Crawford, Field Specialist in Agricultural Engineering, UM Extension, Atchison County

The prospect of a large corn harvest already has many producers looking for storage options. While there are many different options, the most common one is the temporary conversion of machine or hay sheds. Some of the challenges of using these for grain storage include: structural strength, floor surface, grain handling and grain management. Grain vacs have greatly reduced some of the grain handling issues of the past.

The primary challenge of storing grain in existing pole barns is the pressure that the grain exerts on the walls. One method to store grain in a building would be to only fill the building to the point that the grain does not come in contact with the walls.

Adding a four foot tall lining wall to an existing pole barn to four feet high is fairly economical and will not interfere with other uses of the building. Existing poles should be eight foot on center, at least four feet in the ground and no more than 14 feet high. Each post should be cabled to the opposite side post with a minimum 3/8 cable at truss height to prevent the roof from pulling apart. The lining wall is 5/8- or 3/4-inch plywood attached to a stud wall constructed of 2×6 sills and plates holding 2×4 studs, 2’8” on center. When filling the shed, grain should not be piled higher than the 4 foot lining wall or the bottom of the truss. Trusses are designed for the roof load and not any grain load.

Many pole barns do not have a vapor barrier under the floor or even have a concrete floor. If grain is to be stored more than three months some type of vapor barrier should be installed. A 4 to 6 mil plastic sheet can be installed on top of the floor or ground. Make sure that water does not drain into the building.

Other possibilities for temporary grain storage include the use of large bales to form a bin, the use of concrete barriers, construct a circular bin made of plywood four or eight feet deep, silos or silage bags.

Regardless of if it is stored in bins or temporary piles, management is required to keep grain in good condition. Grain should be between 30 and 40°F for winter storage. Maintaining grain temperature below 70°F reduces insect reproduction. Insects become dormant at temperatures below 50°F and are killed below 32°F. Mold growth is nearly zero at temperatures below 40°F.

Any grain stored in temporary piles should be dry and cool. Shoot for an initial moisture content of 13% to be on the safe side.

Because of differences in temperature between the grain in a bin and the outside air, air inside the bin migrates. With cold outside air, the air inside the bin moves downward along the outside wall and then upward toward the center of the bin. The air that comes up through the center of the bin will carry some moisture. As it contacts the cool grain in the center of the bin, moisture will condense and cause the grain in this area to go out of condition and crust.

Crusting will keep air from flowing through the mass of grain and making it impossible to keep the grain in condition. To prevent this problem, grain should be cooled to about 40°F in the fall and warmed to about 60°F in the spring. This will minimize migration of air through the bin.

Check grain weekly. Use a grain probe and a thermometer to check the temperature by probing below the surface of the grain in several places. Record these temperatures to monitor changes. Moving air through the grain can help in determining grain condition. If a musty odor is detected, problems may exist not detected by inspecting the grain or checking the temperature. If problems do occur, fans may need to be run to dry the grain. In some cases, grain may need to be removed from the bin.

Any time a drying or cooling front is started through the grain, make sure the fan runs long enough to move the front completely through the grain. When the temperature of the air coming through the grain is equal to the outside air, drying or cooling is complete.

For more information on these topics as well as other important information regarding proper grain storage and drying, a webpage has been created to address these topics at https://extension2.missouri.edu/programs/grain-management.