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Calcimator

Planting Date Optimizer

Estimate growing degree unit (GDU) accumulation and days to crop maturity from base temperature, daily temperatures, and target GDUs.

Inputs

F
F
F
F
GDUs

Results

Days to Maturity

164 days

Weeks to Maturity23.4 weeks
Daily GDU Accumulation16.5 GDU/day
GDUs in First 4 Weeks462 GDUs
GDUs in First 8 Weeks924 GDUs
Weeks12GDU1,386
Days Simple159
How to Use This Calculator
  1. Select your crop and geographic region or USDA plant hardiness zone.
  2. Enter the average last frost date for your area.
  3. Set soil temperature threshold for germination (e.g., 50 F for corn, 55 F for soybeans).
  4. Review the recommended planting window and expected maturity date.
  5. Use the maturity date to evaluate hybrid or variety selection for your area.

How the result changes with Base Temperature

Base TemperatureDays to Maturity
3689 days
45126 days
57258 days
66450 days

What each input means

Base Temperature
Minimum temperature for crop growth. Corn: 50F; soybean: 50F; wheat: 32F.
Average Daily High
Average daily maximum temperature during the growing season for your location.
Average Daily Low
Average daily minimum temperature during the growing season for your location.
Average Daily Temp
Average daily temperature (used for simple GDU estimate). Usually (high+low)/2.
Target GDUs for Maturity
Total GDUs needed for the hybrid/variety to reach maturity. Check seed company data. Corn: 2200-3000.

How this is calculated

Worked example, using the default values

  1. Identify Input Parameters
    4 parameters
    Base Temperature = 50, Average Daily High = 78, Average Daily Low = 55, Average Daily Temp = 67 = 5 input(s) provided
  2. Calculate Days to Maturity
    Days to Maturity
    164 = 164
  3. Calculate Weeks to Maturity
    Weeks to Maturity = round((daysToMaturity / 7) * 10) / 10
    23.4 = 23.4
  4. Calculate Daily GDU Accumulation
    Daily GDU Accumulation
    16.5 = 16.5

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