From Champion Seed Sales Lead Zach Painter
Post-emergence herbicide applications are essential to protect your crop yield and profitability, but relying on corn height rather than its true growth stage can increase the risk of crop injury. While measuring plant height may seem quicker, it often leads to inaccurate staging — especially during years with uneven emergence, stress or rapid growth.
In vegetative stages, corn growth is determined by counting visible leaf collars, not by plant height. These stages start with VE (which stands for emergence) and end with VT (which stands for tasseling). In between the VE and VT, stages are marked by the letter V and the number of leaves with fully visible collars. For example, a V5 corn plant has five visible leaf collars. However, counting the collars becomes more difficult as the corn plant grows, as lower leaves can die or tear away by the V5 growth stage.
Why does this matter? Many herbicide labels are based on either growth stage or height restrictions, but growth stage is typically the more accurate indicator of crop safety. Environmental conditions can dramatically change plant height without changing physiological maturity. Some could lead to tall corn plants that are physiologically less mature. And others could lead to short corn plants that are further along developmentally.
Improper crop staging can increase the risk of:
- Herbicide injury.
- Brittle snap concerns.
- Ear development damage.
- Reduced weed control timing.
- Off-label applications.
To properly stage corn and ensure crop safety:
- Pull several representative plants from the field.
- Split the stalk lengthwise if needed.
- Count only leaves with visible collars.
- Ignore lower leaves that may have deteriorated or fallen off.
Accurate staging helps ensure safer herbicide applications, better weed control timing and improved overall crop management decisions. Taking a few extra minutes to properly stage corn can prevent costly mistakes later in the season.
