Harvest · June 2025 · 5 min read
Estimating corn yield before harvest helps with marketing decisions, storage planning, and crop insurance claims. Two field methods—ear count and kernel count—give reliable estimates from the milk stage onward.
Count the number of harvestable ears in a 1/1,000th-acre length of row—that's 17 feet 5 inches in 30-inch rows. Multiply the ear count by 90 (a standard kernel weight factor) to get an approximate bushels-per-acre estimate. Repeat at five or more random locations across the field and average the results to account for field variability.
For a more precise estimate, count kernel rows around the ear and kernels per row on five representative ears, then multiply those together for kernels per ear. Multiply by the ears-per-acre count from step one, then divide by the kernel weight factor—typically 75,000 to 90,000 kernels per bushel depending on growing conditions. Stress years push kernel counts toward the higher divisor.
Avoid sampling field edges, end rows, and waterways that do not represent the majority of the field. Sample at least five locations per field in a random pattern, and never pick the best or worst spots. Repeat the estimate at two-week intervals as the crop matures—early-season estimates often overpredict yield because they do not account for late-season stress or tip-back on ears.
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