With harvest wrapped up in most places, many farmers are focused on livestock chores and winter preparations. As the temperature drops, don’t forget to check on your stored grain. Although most of the South Dakota grain harvest was sufficiently dry this year, we still need to watch grain storage temperatures and conditions. I’ve listed a few tips to think about as we move into the cold season:
Cool stored grain
The key to good long-term storage is getting grain cool enough and maintaining that temperature as long as possible; this reduces moisture migration and condensation near the top of the bin. Cooling grain down as temperatures drop in the fall and early winter helps to accomplish this. Keeping grain temps cool also helps to reduce pest issues; temperatures below 60°F reduce insect reproduction and below 50°F cause insect dormancy. Extended exposure to temps below 30°F can kill insects.
Cool grain temperatures reduce mold growth and grain deterioration as well. Use fans to cool grain down to 20-30°F to store over winter. As long as grain is not stored at temps lower than 20°F, there is rarely need to run fans to ‘warm’ grain in the spring.
Grain temperature is the key to long-term storage; allowable storage time doubles (approximately) with every 10°F reduction in grain temperature. Do remember however, that allowable storage time is cumulative. For example: if 20% moisture corn were stored for 25 days at 50°F, half of the storage life has been used. If the corn is cooled to 40°F, the allowable storage time at 40°F is only 45 days. See the attached table for a comprehensive look at grain temperature and storage length.
Fall grain storage tips
• Cover bin aeration fans when not in use. Fans essentially go through the ‘chimney effect’ where wind can move wet or warm air into the fan and it travels upwards, affecting the grain inside. This is especially important for fans placed on the northwest side of bins; the fix can be as simple as a tarp and strap. When covered, be sure to put a safety lock out on the breaker box or switch, to avoid turning fans on when covered.
• Provide an inlet for air near the roof eave and outlet exhaust near the roof peak to allow warm air to exit the bin (much like the principles of an attic). Several vents at the same elevation can still allow heat to remain at the top of the bin without exhaust at the peak or roof exhaust fans.
• Grain temperature should be measured at several places along the walls (especially the south wall) of the bin, near the top surface, and within the grain. Temperature sensors are very useful for this; however, multiple readings are necessary to get an accurate picture of overall temperature.
• Be sure that your fans are large/powerful enough for your bins. To check your bin fans for size, go to the university of Minnesota ‘Fan Selection for Grain Bins’ webpage at https://bbefans.cfans.umn.edu/.
