Keep a close eye on stored corn


If you have corn in bins from the 2009 crop, keep a close eye on its condition. You may need to sell it or dry it right away. Reports of grain spoiling in bins are increasing.

Because of the cool growing season, the wet October, and harvest delays due to dryer capacity and fuel shortages, harvest was late and challenging. Much of the corn came out of the field wetter, with lower-than-normal test weights, and with more fines and kernel damage. Grain molds were common in fields where grain moisture remained high.

“We’ve had a number of reports of on-farm and off-farm storage with poor aeration and hot spots of grain going out of condition,” says George Cummins, Iowa State University Extension crop specialist at Charles City. “We strongly recommend this stored grain be carefully monitored. Check it once a week.”

Key Points

• There is increasing concern about the storability of the 2009 corn crop.

• Lighter-than-normal test weight and wetter-than-normal corn spell trouble.

• Check bins once a week as weather starts to warm in late winter and in spring.


The storability of your corn will be a major factor in marketing plans. Market analysts are predicting a shortage of high-quality No. 2 corn by late summer.

“We are urging anyone who is storing corn from the 2009 harvest to check it and move fast on it if you find problems or if the grain moisture is very high,” says Charles Hurburgh, a grain quality expert who heads the Iowa Grain Quality Initiative at ISU.

Storage life is shortened

Last fall a lot of corn didn’t get dried down completely, and much of the crop had a lighter-than-normal test weight. That corn has roughly half the storage life of normal corn. Corn in bins that were aerated properly and monitored to stay below 30 degrees F grain temperature are generally in good condition. But corn in a number of unaerated bins and piles is deteriorating. Some have reached 75% to 100% damaged kernels.

The estimated allowable storage time, or AST, decreases rapidly at warmer grain temperatures. For 26% moisture corn, the AST for normal corn is about 90 days at 30 degrees F, 35 days at 40 degrees and only 12 days at 50 degrees. For 22% moisture corn, the AST is about 190 days at 30 degrees, 60 days at 40 degrees and only 30 days at 50 degrees. For 20% moisture corn, the AST is fairly long at 30 degrees, but is about 90 days at 40 degrees and 50 days at 50 degrees. Remember, immature, cracked and broken kernels are more prone to deterioration than good-quality corn.

When outdoor temperatures rise in late winter and in spring, the warming of grain will normally be limited to a couple feet near the bin wall and a few feet at the top of the bin. You need to monitor grain temperature in these locations to determine when to operate the aeration fan, advises Hurburgh.

Bin temperature cables help monitor grain temperature, but will only detect the temperature of the grain next to the cable. Grain has an insulation value of about R1 per inch. Grain insulates the cable from hot spots that may be occurring just a few feet from the cable.

 Source: Iowa State University

Beware of molds

Grain molds can cause severe respiratory problems and are a health hazard for workers. Always use proper protective equipment when cleaning out grain bins or handling moldy grain.

The Agrisafe Network at www.agrisafe.com or Gempler’s at www.gemplers.com will show the types of available face masks and respirators to use. Select the protective equipment recommended for handling moldy grain.


This article published in the February, 2010 edition of WALLACES FARMER.

All rights reserved. Copyright Farm Progress Cos. 2010.