Growth Stages & Spray Timing

Corn: V-stages by collars, R by ear

Count visible leaf collars — V6 has six. Late-vegetative is where herbicide labels start cutting you off (many post herbicides stop at V6–V8 or a plant height, whichever comes first — read both). VT is tassel fully emerged; R1 silking. The VT–R1 window is the classic fungicide timing: you're protecting the ear leaf and above during grain fill. R5 is dent; by then a fungicide has little left to protect.

Soybeans: nodes, then flowers and pods

V-stages count nodes with fully developed leaves. R1 = first open flower, R2 full bloom, R3 pod 3/16" at one of the top four nodes, R5 seed beginning. Most foliar fungicide value sits at R3 (with white mold decisions earlier at R1). Post herbicides typically cut off around R1–R2 — spraying a flowering bean off-label is a common, avoidable violation.

Wheat: Feekes/Zadoks basics

Key marks: tillering, jointing (herbicide cutoffs cluster here), flag leaf emergence, and heading/anthesis — the window for head scab (Fusarium) suppression, which is timing-critical to a few days at flowering.

Staging mistakes that cause violations

• Staging from the field edge — headlands are ahead or behind the field average.
• Counting corn leaves instead of collars (inflates your stage; you spray past the cutoff).
• Ignoring the "or plant height" half of a label restriction.
• Treating one field's stage as the whole farm's — plant on different days, stage separately.

How to stage in 3 minutes

1. Walk 30+ paces in from the edge, in a representative area.
2. Stage 10 consecutive plants; use the average, not the tallest.
3. Repeat in a second spot; if they disagree, split the field for application.
4. Write the stage in your record — it's your proof you were legal.

Staging conventions per standard extension guides; product labels govern legality. Tool: fungicide timing by stage.