Free calculator · No signup
Cotton Heat Units Calculator (DD60)
Calculate cotton growing degree days (base 60°F) and track progress toward each stage.
Your numbers
Result
How it's calculated
DD60 = (daily high + daily low) ÷ 2 − 60, never less than zero. Cotton development is driven by heat, so accumulated DD60 from planting predicts stage far better than calendar days.
| Stage (from planting) | Approx. DD60 |
|---|---|
| Emergence | 50–60 |
| First square | ~475–525 |
| First bloom (flower) | ~825–875 |
| Peak bloom | ~1,400 |
| First open boll | ~1,700–1,800 |
| Defoliate (60% open) | ~2,200–2,600 |
Milestones are approximate and vary by variety and region — use them as a guide, not a guarantee.
Row Wise accumulates DD60 from your field's actual weather automatically and flags every growth stage — no daily spreadsheet.
Get notified at launch →Frequently asked questions
What are cotton heat units or DD60?
DD60 (growing degree days, base 60°F) measure the heat a cotton crop accumulates each day: the day's average temperature minus 60. Cotton grows on heat, so DD60 tracks development better than days on the calendar.
How many heat units does cotton need?
Roughly 50–60 DD60 to emerge, about 800–850 to first bloom, and around 2,200–2,600 from planting to defoliation — though this varies with variety and conditions.
Why base 60 for cotton?
Cotton makes little growth below about 60°F, so 60°F is used as the lower threshold. Corn and sorghum use base 50.