Maize Heat Unit Tool

KWS' online tool enables you to check your predicted grain harvest date based on the FAO of your selected hybrids, and the average heat units for your location.

Please note, this tool is for grain harvest only. For forage harvest, we recommend harvesting 3-4 weeks earlier than the recommended date for grain harvest, depending on ripening conditions. If you would like to check your predicted forage harvest date, please use alternative methods.

  • Your predicted grain harvest date is shown based on the crop reaching a grain kernel moisture content of 35 %.
  • Enter your full UK postcode (space needed).
  • Enter your sowing date (day and month, e.g.: 23, 4 (April) or 23 , 5 (May)).

Development from sowing

    Are you curious about a recommendation at the time of ripening?

    Are you interested in predicting the optimal harvest time and want to see the heat total for your region? Then please register with our free myKWS.

    Learn more about myKWS

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    Sowing date

    Latest Harvest Date (NB: full grain maturity)

    Predicted harvest date based on 5 year average. *

    Actual silage harvest is around 3-4 weeks before this depending on ripening conditions.

    * Heat Unit Calculator based on AGPM Base 6deg. C Min/Max Calculation.

    • Current Heat Units
    • Previous years (10-year average)
    • Required heat units based on the crop reaching a grain kernel moisture content of 35 %

    Source: Iteris, Inc.