Growing Degree Units (GDU)
GDU = max(0, (Tmax + Tmin)/2 − Tbase). Base 50°F for corn. Accumulates daily. Predicts growth stage and maturity.
Why This Biology Metric Matters
Why: Heat accumulation drives crop development. GDU predicts growth stage and harvest timing. Base temp is crop-specific.
How: GDU = max(0, (Tmax + Tmin)/2 − Tbase). Corn base 50°F, wheat 40°F. Sum daily GDUs for accumulated total.
- ●Corn base 50°F. Wheat 40°F. Cotton 60°F. Crop-specific.
- ●Accumulated GDU maps to growth stages. Predicts maturity date.
- ●Below base: 0 GDU. Caps at max temp for some formulas.
Calculate Growing Degree Units (GDU) to track crop development. Predict growth stages and maturity for corn, wheat, soybeans, cotton.
Compact Examples
Corn Planting to Silk
Calculate GDU accumulation from planting to silking stage
Wheat Development Tracking
Track wheat growth through key development stages
Cotton Emergence to Bloom
Monitor cotton development from emergence to first bloom
Full Season Accumulation
Calculate total GDU accumulation for entire growing season
Enter Temperature Data
⚠️For educational use only. Always confirm dosages and care with a licensed veterinarian.
🧬 Biology Facts
GDU = (Tmax + Tmin)/2 − Tbase. Negative = 0. Daily accumulation.
— Extension
Corn base 50°F. ~2700 GDU to maturity for full-season hybrid.
— USDA
Wheat base 40°F. Cool-season crop, lower base.
— Purdue
GDU predicts growth stage. Used for irrigation, pest, harvest timing.
— Extension
📋 Key Takeaways
- • GDU = ((Max + Min)/2) - Base. If negative, GDU = 0.
- • Corn base 50°F, wheat 40°F, cotton 60°F. Crop-specific.
- • Accumulate daily GDUs to predict growth stages and harvest.
- • Use for planting, irrigation, fertilizer, pest, harvest timing.
💡 Did You Know?
📖 How GDU Calculation Works
GDU = ((Max + Min)/2) - Base. If result < 0, GDU = 0. Accumulate daily.
Core Formula
GDU = ((Max Temp + Min Temp) / 2) - Base Temp
🎯 Expert Tips
💡 Daily Tracking
Best accuracy. Weekly still useful.
💡 Match Base to Crop
Corn 50°F, wheat 40°F, cotton 60°F.
💡 Use for Timing
Planting, irrigation, fertilizer, harvest.
💡 2–3 Day Accuracy
Under normal conditions. Stress affects.
⚖️ Crop Base Temperatures
| Crop | Base °F | Base °C |
|---|---|---|
| Corn (Field Corn) | 50 | 10.0 |
| Wheat | 40 | 4.4 |
| Soybeans | 50 | 10.0 |
| Cotton | 60 | 15.6 |
| Rice | 50 | 10.0 |
| Barley | 40 | 4.4 |
❓ Frequently Asked Questions
GDU vs GDD?
Same. Interchangeable. Growing Degree Units = Growing Degree Days.
Why different base temps?
Cool-season (wheat 40°F) vs warm-season (cotton 60°F).
Can GDUs be negative?
No. Below base = 0 GDU for that day.
How accurate?
Within 2–3 days under normal conditions.
Track daily?
Best. Weekly/bi-weekly still useful.
📊 GDU by the Numbers
📚 References
⚠️ Disclaimer: Educational only. GDU accuracy varies by stress, weather. Use for planning, not guarantees.