“All growers should recognize the stages of corn growth,” Dave Nanda says. “It gives them a better understanding of how corn plants grow. Plus, key things happen within corn plants at certain growth stages. Identifying the stage of growth can help determine how plants may react. Also, if you’re applying postemergence herbicides, you must recognize growth stages to follow the product label.”

Nanda is director of genetics for Seed Genetics Direct, sponsor of Corn Watch ’22. This series will follow what happens in one cornfield in central Indiana, pointing out things you might see in your fields. Nanda will share his observations throughout the season and draw on experiences from previous Corn Watch years.

Growth stage notes

Here are some tips for staging early corn plants:

Find a good guide. The Purdue University Corn and Soybean Field Guide shows clear pictures of corn at various stages, including a V3 and V4 corn plant. Nanda follows the leaf collar method. Only leaves with collars exposed count toward a leaf. In this method, don’t count the top leaf, which often droops but doesn’t yet have a collar.

Start with the rounded leaf. On small plants, the first leaf to emerge is still visible. It has a rounded tip.

Know the method. If herbicide labels refer to plant growth stage, determine if they’re using the leaf collar method. Some still refer to corn height, which usually means height from the ground to the tip of the uppermost leaf.

Identify crucial V5. At or just after plants reach this stage, the growing point emerges, and is vulnerable to hail and freeze damage. Corn plants damaged once the growing point is above ground usually will not regrow.

Also, the number of kernel rows per ear is set around this stage. It’s highly tied to genetics but can be influenced by environment.