Time to Get your Grain Bins Ready for Harvest

By Kristina TeBockhorst

Before the rush of harvest gets here, take some time to get your grain bins ready for a new crop. The first step in minimizing grain spoilage from insects is to start with a clean bin. Grain-feeding pests can survive on residual grain, broken kernels, fines, foreign material, and molds accumulated inside grain bins and around the bin perimeter. To reduce infestations, limit accessibility by sealing gaps and cracks, cleaning grain-handing equipment, remove all potential food sources, and in some cases applying insecticides.  

Check mechanical parts of the bin while it is empty and conduct any maintenance needed before new grain is stored. Seal any gaps or cracks along the bin to prevent insect and moisture entry. Check the roof closely around the vents or access doors, as those are common spots for leaks. Also clean out harvesting and handling equipment, like combines, trucks, wagons, and augers, to remove all dust and debris that can harbor mold and insects.

Sweep the bin walls and floor, make sure to clean the tops of doors, inside hollow pipes or ladders, and inside of augers. If possible, remove the aeration floor and clean out all accumulated food materials. Some bin designs make under the floor cleanup a bit easier with removable floor panels throughout the bin or blow-out doors that can be opened to blow out material accumulated below the floor. If fines or Indian meal moth silks are starting to plug up the space below the floor, it is time to remove the floor to vacuum or power wash.

Trim down vegetation around the bins, equipment, and storage buildings to reduce any potential refuge areas between seasons. Remove any residual grain or debris around the bin. Consider using a rodenticide around the bin’s outer perimeter.

If the aeration floor can’t be removed, fumigation is the best option to eliminate carryover insects. Strongly consider fumigation if insect activity caused issues for recent grain in storage. Follow label instructions and use extreme caution when applying fumigants or consider hiring a trained and licensed fumigation specialist. Consider an insecticide application to the clean walls and floor in the bin and around the exterior perimeter, especially if you are considering storing grain past the spring into summer months. Some insecticides could also be applied to grain as you fill the bin or as a surface application, such as insecticides for Indian meal moths. Oklahoma State University Extension officers excellent insecticide and fumigant recommendations for grain protectants and grain storage facilities.

When adding a new crop to the bin, use these three basic grain storage principals to prevent storage quantity and quality loss:

1. Store clean grain
   • Use proper combine settings to limit grain damage and reducing the collection of fines and foreign materials.
   • Clean the grain before putting it in the bin if fines are still a problem after adjusting combine settings.
   • Minimize drop height in the grain system and reduce kernel damage by using cushion boxes to minimize grain-on-grain contact.
   • If a grain spreader is not used, core the grain mass multiple times as the bin is filled to remove fines, broken kernels, and foreign materials that naturally accumulate in the center core. A level surface will also improve aeration through the grain mass.
2. Store dry grain
   • Follow grain storage moisture content (MC) recommendations, which are typically recommended as 15% for corn grain stored through the winter and 13% when stored past the spring into summer. For soybeans, MC recommendations would be 13% and 11%, respectively.
3. Store cool grain
   • Cool grain to below 40 degrees F as soon as ambient temperatures will allow in the fall. Insect development, including feeding, is reduced below 50 degrees F as insects become inactive. If grain is binned when temperatures are still warm, plan to cool the grain every time the ambient temperature is 10 degrees F lower than the grain temperature until grain is cool for winter storage.
   • Run a full cooling cycle for aeration fans. Check that the grain at the top of the bin is cool, as this is the last grain to cool when fans push air up through the grain.
   • Run aeration cycles throughout the storage period to ensure grain temperature remains cool and even throughout the grain mass. Grain under the roof and near the walls can collect solar heat as the roof and wall steel is warmed by the sun.
   • Find more information on cooling grain in the fall here.

Seal aeration fans when not in use to prevent warm or moist air and insects from entering the grain mass. Monitor grain at least every other week to check for insect activity and signs of spoilage, such as crusting, damp/warm spots, musty or sour odors, or rising CO₂ levels with a handheld CO₂ monitor.