Corn Loading into truck

Editor’s note: The following was written by Kristina TeBockhorst and Shawn Shouse, Iowa State University Extension agricultural engineering specialists, for the university’s Integrated Crop Management blog.


Many farmers put grain in the bin wetter than normal last fall and were somewhat rescued by the cold weather.

In the coming weeks as spring starts to bring warmer temperatures, grain held through the winter at a high moisture content should be dried or marketed as soon as possible to prevent quality loss and mold growth.

Monitor grain condition and act fast if hot spots, a musty/moldy smell or elevated CO2 levels (above 600 ppm and rising) are observed.

Grain held this winter at a very high moisture content (above 20%) may have already used its safe allowable storage life. For this grain, it may not be advised to attempt to store it any longer after drying it this spring. Be sure to account for a shorter allowable storage time with low test weight and low-quality grain.

Wet grain should be dried as soon as spring temperatures start to warm. Conditions become suitable for natural air/low-temperature bin drying when average daily temperatures are above 40 degrees.

The air dewpoint temperature gives a good indication of whether air has much capacity to dry. A 20-degree difference between the air temperature and the air dewpoint temperature indicates good conditions for drying.

Do not warm grain that is already dry if you intend to keep storing it. Instead, run aeration cycles in cool weather to maintain grain temperature below 40 degrees. A large drying fan can cool a bin in about 15 hours, while an aeration fan will take close to a week to cool a bin.

If grain temperature is well below freezing, such as 20 degrees, gradually warming it to just above freezing may prevent excessive condensation and frozen chunks this spring or summer.

With the potential for poor quality grain in the bin, it is especially important to use good grain safety practices. Poor quality grain can cause problems such as surface crusting, hollow spots in the grain mass, grain that won’t flow when unloading and sidewall buildup in the bin. Do not enter a bin if any of these occur, and instead attempt to work on the grain from above by poking and prodding it.

If you have good-quality grain and you must enter a bin, have an observer with you, use a life harness, and lockout/tagout grain equipment to keep it off.