Following Current Corn Growth Stages

Jarrod O. Miller, Extension Agronomist, jarrod@udel.edu; Cory Whaley, Sussex Co. Extension Ag Agent, whaley@udel.edu; James Adkins, Irrigation Engineer, adkins@udel.edu and Jake Jones, Extension Agriculture Agent, Kent County, jgjones@udel.edu

In 2019 we followed several corn planting dates to evaluate emergence and growth stages across Delaware. Fields planted in late April and early May took 7 to 10 days to emerge and 22 to 25 days to reach the V4 stage. This year, over the same time period, corn has taken 9-13 days to emerge, and the earliest planted field we found took 24 days just to reach V2. The weather has been cooler the last few days, and lowered heat accumulation again (Figure 1).

There is a good chance that many fields planted in mid-May will not be as far behind those planted the week before, as they accumulate growing degree days (GDD) at a more rapid pace. This can be seen in Table 1, where corn planted in New Castle County on May 6^th or 13^th would accumulate very similar GDD. Sussex County has been a little warmer but was still limited in heat units from May 2-13^th (Figure 1). Keep track of your fields and scout for stages, as you may be sidedressing fields a little later than you expect.

Table 1. Accumulated Growing Degree Days Based on Planting Date

Figure 1. Accumulated Growing Degree Days in each County Since April 15^th.