NDSU Explains Silage Moisture Needs After Corn Frost

By Scout Nelson

Recent frost has damaged many acres of corn across North Dakota, and the extent of injury depends on how cold it became, how long the temperature stayed low, and the crop’s maturity stage.

North Dakota State University (NDSU) Extension forage crops production specialist James Rogers says frost-damaged corn can still be chopped for silage, but careful moisture management is essential for quality feed.

Rogers explains that proper moisture at ensiling is key for good fermentation and preservation.

Although frost-damaged plants may quickly change color from green to gray, the internal moisture may remain too high. Harvesting corn at the milk stage immediately after frost can result in wet, sour silage and nutrient loss from excessive seepage.

The recommended whole-plant moisture for most silage structures is 62% to 68%. Corn will ensile at up to 75% moisture in a bunker or trench silo, while bag silos work best between 60% and 70%.

Moisture levels vary by growth stage. Corn at the milk stage averages 80% moisture and needs time to dry to the ideal range. Allowing this natural dry-down may slightly reduce yield but improves silage quality.

Rogers cautions that milk-stage corn can develop mold in the ears, and some molds may produce harmful mycotoxins. Samples can be tested for mycotoxin levels at the NDSU Veterinary Diagnostic Laboratory.

Corn in the dough stage typically contains around 75% moisture and may require several days of drying to reach the proper level. Corn at the dent stage usually has 70% moisture and, if frost occurs in mid- to late-dent, should be harvested as soon as possible.

Rogers adds that nitrate levels can be higher after frost, but harvesting for silage helps reduce those levels.

By monitoring plant moisture, allowing proper dry-down, and testing for mold and nitrates, producers can turn frost-damaged corn into high-quality feed while protecting livestock health.

This guidance helps farmers protect feed value and maintain strong silage fermentation even after unexpected frost events.

Photo Credit: gettyimages-dale-fornoff