How Much Does Late Planting Really Cost You?

Planting date decisions are among the highest-leverage choices in crop production. University research across the Corn Belt puts real numbers on the cost of delayed planting.

The Yield Penalty Data

Purdue University's long-term research shows corn yield potential peaks with planting dates between April 25 and May 5 in most of Indiana and Illinois. After May 10, expect roughly 1–1.5 bu/acre per day in lost yield potential. After May 20, the penalty accelerates to 2+ bu/acre per day.

For soybeans, the optimal window runs a bit later — May 1 through May 20 in the northern Corn Belt. But soybeans are more forgiving of late planting than corn, with smaller daily penalties.

The Real-World Math

At 180 bu/acre corn average and a 1 bu/day penalty starting May 10, planting on May 20 instead of May 5 costs you roughly 15 bu/acre. At $4.50/bu, that's $67.50/acre in lost revenue. Against a typical variable cost of $400–$500/acre, that's a 13–17% margin impact from planting timing alone.

When the Math Changes

Waiting for better field conditions is sometimes the right call. Compaction from planting in wet conditions can reduce yield as much or more than the planting date penalty. The rule of thumb: if you're leaving tracks that don't spring back, you're doing more damage than the calendar penalty.

Practical Takeaway

Know your break-even yield and run the numbers before pushing through wet fields. A two-day wait for proper conditions often costs less than a week of fighting compaction all season.