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Cotton Defoliation Timing Calculator
Check defoliation readiness from percent open bolls and nodes above cracked boll (NACB).
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How it's calculated
Percent open = open bolls ÷ total harvestable bolls × 100. The two common triggers are ~60–75% open bolls, or 4 nodes above cracked boll (NACB) — the count of main-stem nodes above the uppermost first-position cracked boll.
Defoliating too early sacrifices the top crop and micronaire; too late risks weathering and regrowth. The two methods together give a confident call.
Row Wise's defoliation and harvest-window advisor tracks heat units after cutout and boll opening for every field, so you time the strip right.
Get notified at launch →Frequently asked questions
When should cotton be defoliated?
The usual targets are 60–75% open bolls, or 4 nodes above cracked boll (NACB). Both indicate the crop has matured its harvestable bolls and can be safely defoliated.
What is NACB?
Nodes above cracked boll — count the main-stem nodes above the highest first-position boll that has cracked open. At about 4 NACB the uppermost harvestable bolls are mature enough to defoliate.
What happens if I defoliate too early?
Immature bolls won't open properly, cutting yield and lowering micronaire and fiber quality. Waiting for the targets protects both the top crop and the grade.