Soil temperature map can guide planting decisions

     Soil temperature is one of the most important factors crop farmers use to guide their planting decisions. The rule of thumb is to wait until the upper 4 inches reach at least 50 degrees Fahrenheit, with a warming trend in the forecast.

     One way farmers can keep track of soil temperature in their county and across the state is by using the soil temperatures map compiled by the Iowa Environmental Mesonet at Iowa State University. Updated daily in the spring, this map provides current and historical soil temperatures for each county in Iowa.

     As of April 7, soil temperatures ranged from 46 F in southern Iowa, to as low as 33 F in the north.

     Daily fluctuations are common, especially in early spring. Historically, the optimum planting window for Iowa corn has been April 11 to May 18, with a shorter window in the northern part of the state compared to the south.