Optimal Conditions for Planting Soybeans
Better planting equipment, improved soybean genetics and technology advancements such as seed treatments and weed control systems have moved soybean planting dates earlier in recent years. Last year 34% of Iowa’s soybean crop was planted by early May; this year only 1% of Iowa’s soybean acres are planted as of May 13.
Although there is a correlation to higher yield potential with earlier planting dates, it’s important to remember that soybeans respond favorably to early-planting dates IF soil conditions are ideal for planting. Remember: (1) There's no need to be concerned that soybeans are being planted "late" in mid-May. (2) Conditions weren’t fit for planting soybeans in late April or early May as many soils were too wet and too cold.
One silver lining in the delayed soybean planting is that soil temperatures have warmed greatly. We recommend planting soybeans when soil temperatures are about 60 degrees, and soil temperatures were averaging only in the low 60s around May 15.
Planting into a field that is too wet or too cold early in the season will reduce emergence and plant population, which most often leads to reduced yield. Remember, planting soybeans in warm but wet soils can also have a detrimental impact on yield. Patience is key this planting season!