An early frost in some areas has producers wondering what to do with immature frost-damaged soybeans.

“Soybeans killed at growth stages of full seed development and beginning maturity should be left out in the field to dry and harvested along with mature soybeans,” advises Ken Hellevang, retired North Dakota State University Extension agricultural engineer.

Hellevang explains that weather conditions during the field drying period after plants are frozen impact the color of the harvested soybeans. Soybeans at a maturity stage of R6 are expected to continue to change from green to yellow when exposed to sunlight while drying in the field to the desired harvest moisture content. The beans are expected to develop a golden yellow tone approaching that of mature soybean (R8), and the extracted oil is expected to change from green to a golden color as the chlorophyll dissipates with exposure to sunlight.

However, R6 soybeans that are field-dried during a period lacking in sunlight will likely exhibit a green tone to the golden color. Despite the bean’s yellow/green tone observed after field drying, little green color is expected in the extracted oil from the seeds.

Frozen soybeans may dry differently in the field than soybeans that were not frozen, so there may be different moisture contents within a field.

“Soybeans can trick grain moisture meters,” says Hellevang. “The outside of a soybean may be drier than the inside, resulting in an inaccurate moisture test.”

Hellevang recommends putting a sample of soybeans in a sealed bag for several hours at room temperature to allow the moisture to balance out and provide a more accurate reading.

Shatter losses have been shown to increase significantly when seed moisture falls below 11% and when mature beans undergo multiple wetting and drying cycles, so determining when to harvest may be more challenging with frozen soybeans.

Soybean moisture variation may lead to storage losses. Operating an aeration fan will help move moisture from wet beans to drier beans. Air going past wet beans picks up moisture, and that moisture will transfer to drier beans as the air goes past them. Moisture movement will be minimal without aeration airflow.

If there is a variation in harvest and storage moisture contents, Hellevang suggests initially running the fan longer than is required to cool the grain to even out the moisture content. The moisture will not be all the same, but it should become more uniform.

For more NDSU Extension information about soybeans, visit ndsu.ag/frostsoybeans.

NDSU Agriculture Communication – Sept. 23, 2025

Source: Kenneth Hellevang, 701-261-9869, kenneth.hellevang@ndsu.edu

Editor: Dominic Erickson, 701-231-5546, dominic.erickson@ndsu.edu