Video – How to Identify Corn Vegetative Growth Stages

Vegetative growth stages of corn or sorghum are determined by counting the number of fully emerged leaves with leaf collars present.  Only those leaves which have a leaf collar visible at the base of the leaf where it connects with the stem are fully developed and count as an appropriate growth stage.  Corn vegetative growth stages are designated by a V with a number following representing fully developed, emerged leaves.

The most difficult part of this process is to account for all the leaves, including the oldest or smallest leaves at the bottom of the stem, which may gone or hard to find on older plants. These leaves naturally senesce and tear away from the stalk as the stem elongates and nodal roots develop. If you look closely, you may be able to find remnants of these older leaves.  Also, you can familiarize yourself with the relative length of the oldest leaves, so you can recognize them. The first leaf is always rounded at the tip and is 1.75 to 2 inches long, the second leaf is about 3.5 to 4 inches, the third leaf is 6 to 7 inches, and the fourth leaf is usually about 8 to 10 inches.

This is a video showing how to determine corn vegetative growth stages in the field.

How to Identify Corn Vegetative Growth Stages