Warmer Temperatures Have Helped Corn Along

Jarrod O. Miller, Extension Agronomist, jarrod@udel.edu

Temperatures in the upper 80s last week helped produce the degree days needed for corn to emerge. Most fields we have observed have had emergence in about 6-7 days from planting. The corn in the photo below was planted on April 30th and was already above the soil by May 7th.

The table below estimates the growing degree days observed in each Delaware county over the last two weeks. Corn needs to accumulate between 100 to 125 GDD to emerge, so all three counties have accumulated the necessary warmth to get corn going since April 22-29th. If temperatures continue like normal, hovering in the 70s during the day (11-12 GDD per day), we can expect 8-10 days until emergence. If temperatures reach the upper 80s again and we accumulate 16-17 GDD, it may only take 6-7 days. So keep your eyes on the temperatures to predict when emergence may occur.

Table 1: Growing degree days accumulated over the last few weeks and the overall average per day.

  Sunday, April 22 Sunday, April 29 Sunday, May 6
Sussex 185 133 25
(GDD per day) (12) (16) (13)
Kent 182 136 26
(GDD per day) (11) (17) (13)
New Castle 158 125 27
(GDD per day) (11) (16) (14)