Corn field at sunsetCorn goes through a number of stages from planting to harvest. The ability to identify those different stages helps growers work efficiently in their fields, from knowing the correct herbicide application window to understanding when it’s time to pull tissue tests. To help understand which stage corn is in, some turn to the Purdue Corn & Soybean Field Guide. During the early part of the growing season, it recommends the following to identify corn growth stages.

Begin with the first true leaf. According to the guide, it will be the first to emerge and will have a rounded shape compared to those that come after it.

Focus on leaves that have collars. Count each leaf with a collar, identifiable by the lighter green or yellow band near the stalk. The time of day will influence the count. Collars that appear to be barely-there in the morning count. Later in the day, farmers should ignore collars that are hard to see. The number of collars on the plants in the field determines the growth stage. If there are three collars, the corn is in V3.

Read more about corn growth stages here.