Corn Silage Dry-Down: Week of September 21, 2026

Corn silage moisture content continues to be critical to harvesting a high-quality and high-yielding forage crop. Extension educators across Pennsylvania are working with cooperating farms to harvest, chop, dry, and track the moisture content of corn silage fields around the state. Table 1 includes crop progression for the week of September 21st, with the following definitions:

• Accumulated Growing Degree Days (GDD): A measure of the accumulated growing degree days counted at this location since planting. Calculated using 86/50-degree cutoffs.
• Dry-Down Rate: The rate at which a particular hybrid is losing moisture each day, as compared to the previous moisture check. Rates will average about 0.5% moisture loss per day, ranging between 0.0 and 1.0% in extreme weather.

Be cautious of localized differences in planting date, hybrid maturity, and weather conditions. Not all hybrids will progress through dry-down the same, and not all hybrids retain the same appearance at a certain moisture content. Be aware of expected weather in the coming weeks; if cooler weather trends continue into September, crop maturation may slow considerably. Table 2 highlights the target crop moisture levels for an efficient fermentation that minimizes losses to seepage or mold.

For a comprehensive review of best management practices for harvesting, storing, and feeding silage, please see From Harvest to Feed: Understanding Silage Management.

Many thanks to the county-based Penn State Extension Dairy and Agronomy Educators who make this effort possible, including: Angie Breneman (Lancaster), Stephen Campbell (Butler), Zack Curtis (Wayne), Kasey Hower (Berks), Tosh Mazzone (Franklin), and Heidi Reed (Lancaster).