Ask the Doctor: Guiding Crops through Spring’s Changes

Yes, customers should warm their stored grain to 60–70 °F during summer, maintaining a temperature approximately 10–15 °F below ambient conditions. For example, if the average ambient temperature is 80 °F, grain should be held at 65–70 °F. This temperature differential helps prevent condensation. Grain temperatures above 70 °F promote insect activity; therefore, 70 °F should be considered the upper limit whenever possible.

If a customer receives a hotspot alert, this indicates a true hot spot caused by heat from mold damage. They typically develop when relative humidity exceeds 65% and grain temperatures rise above 60 °F.

As grain temperature increases, allowable safe storage moisture decreases, meaning relative humidity within the grain rises above 65%—an environment that promotes mold growth.

For example, safe storage moisture content for current corn hybrids is approximately 14% at 40 °F and 13% at 70 °F. If corn is stored at a market-approved moisture content of 15% and warms to 70 °F during summer, the conditions can lead to mold-related hotspots. When temperature increases at the same time as condensation, it accelerates mold development, which is a true hotspot.

For soybeans, when the temperature increases with a grain moisture content of 11-12%, the risk of mold growth is accelerated, which also leads to caking. Normally, this happens during the soybean hydration process.

Wheat and barley are typically harvested when ambient temperatures range from 70–80 °F. To preserve grain quality, temperatures should be reduced to below 70 °F using cooler nighttime air. Proper aeration during this period helps remove accumulated moisture and maintains uniform temperature throughout the grain mass.