Corn — GDD Requirements by Growth Stage

Overview

Corn (corn) requires cumulative temperature (GDD) for growth. The growth progress is managed based on the accumulated temperature. GDD primarily begins with germination and continues through vegetative growth, flowering (heading/pollination), and ripening/maturation, with each growth stage having unique GDD requirements. By knowing this cumulative temperature, it is possible to judge the appropriate time for sowing and harvesting, select varieties, and adapt cultivation areas with high precision. This report details the GDD requirements for each growth stage, the common concept of base temperature, and variations due to differences in variety and environment, based on data from domestic and international academic literature and agricultural extension organizations (preferentially information in Japanese).

Definition and calculation of cumulative temperature (GDD)

In many cases, the GDD of corn is calculated using a reference temperature of 10°C (base temperature). Daily GDD is calculated as follows:

• GDD = ((daily maximum temperature + daily minimum temperature)/2) - 10°C
  *The upper and lower limits are often adjusted at 30°C for daily maximum temperature and 10°C for daily minimum temperature [1][2].

Cumulative temperature for each growth stage (GDD)

1. Germination (Emergence／Germination)

• Accumulated temperature requirements: 120-175°C (simple integration) or 90-120 GDD (10°C base)
• Representative domestic values: Even in cold regions such as Hokkaido, germination and germination are reached at around 120 to 150°C (simple addition)
• Overseas values (10°C base GDD) are around 90 to 120 GDD
• Key points: Soil temperature at the time of sowing is 14°C or higher, optimal germination temperature is 25-30°C, minimum is 10°C [3][4][5]
• Supplement: The risk of germination failure is greatly influenced by environmental factors such as soil temperature and soil moisture

2. Vegetative Growth

• Cumulative temperature requirements (cumulative):
  • From germination to flowering (heading/silking), mainstream varieties are 1,100 to 1,400°C (simple GDD, sowing → flowering) or approximately 1,200 to 1,500 GDD (10°C base)
• By leaf age and leaf stage:
  • V1 to V6 (1st to 6th leaf stage): Approximately 82 to 85 GDD per leaf (initial stage) → Add approximately 50 GDD to each leaf thereafter
• Main points: GDD, which subdivides the number of leaves and intermediate growth, is abundantly available at universities in the United States, and requires 1,200 to 1,500 GDD before flowering (silking) [1][6].

3. Flowering/Pollination (heading/silking, Flowering)"">​

• Accumulated temperature point: Earing and filamentous flowers (silking) are approximately 1,200 to 1,400 GDD (Japan) and 1,400 to 1,500 GDD (USA) from sowing.
• Notes: At this time, temperature stress and moisture conditions greatly affect high yield and the start of ripening [6][7][8].

4. Grain Fill/Maturity

• Ripe to yellow ripening period:
  • After silking, add 800 to 900 GDD (about 2 weeks) to yellow ripening period (30% dry matter harvest, for silage)
• Physiological ripeness (black layer reached, R6):
  • From silking to full ripeness totalapproximately 800-900GDD (2,000-2,300GDD from sowing) (RM85-95 variety in Japan)
  • 2,700-3,100GDD for mainstream U.S. dent corn varieties trong>[1][6][9]
• Early maturing varieties:
  • Achieves maturity at a simple cumulative temperature of around 2,000 to 2,100°C (for Hokkaido and high latitude areas)
• Main points: The ripe mark (black layer) can be predicted with high accuracy by adding GDD from silking, regardless of the sowing date [1][8].

Differences in GDD and considerations depending on variety/environment

Variety/Early Maturity (RM: Relative Maturity)

• Early Maturity: The required GDD is about 100-130°C (GDD) lower than late-season varieties, and adaptability to cold regions (Hokkaido RM75-85 = around 2000°C from sowing to yellowing) Refer to the expected cumulative temperature achievement of the cultivation area and the RM value (relative maturity days) [1][5][9][10].

Environmental factors

• Region (latitude, altitude), weather: The cumulative GDD up to the stage varies depending on the annual average temperature and temperature changes during the growing season, even for the same variety.
• Cropping type: The GDD accumulation efficiency differs between single-season and double-season crops, and there are reports of two-season crops being introduced in the warm regions of western Japan [5][8].

Management/Practical Application

• GDD Field Observation: Local GDD is calculated from weather data + records of sowing/silking dates, enabling accurate setting of yellow ripening period and appropriate harvest time
• Agricultural extension technology:Sanatec Seed, Pioneer, etc. provide integrated temperature calculation programs for free [1][7].

List of GDD for each growth stage (Representative value)

Growth stage	Accumulated temperature (Japan, simple GDD, 10°C base)	Accumulated temperature (overseas, 10°C base)	Explanation/Notes
Germination/Emergence	120～150	90～120	Soil temperature 14°C or higher, 5-7 days later
Vegetative growth (leaf growth, VE~VT)	1,000~1,200	1,100~1,400	About 80GDD for each leaf age, 50GDD calculated thereafter
Flowering/emergence Grain (Flowering) Fill/Mat.)	2,000-2,300 (ripe)	2,700-3,100 (ripe)	Silking - Ripe 800-900GDD added

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Overview

In order to manage corn growth and harvest at the appropriate time, it is essential to accurately understand and observe the cumulative temperature (GDD) at each growth stage. It is highly consistent with Japan's mainstream cultivation areas, standard varieties, and overseas academic values, and the basic principle is management at an average base temperature of 10°C. By selecting appropriate varieties and monitoring growth progress, taking into account the differences in GDD requirements due to differences in varieties and cultivation areas, it is possible to contribute to stable production and improved yields.

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Sources

[1] Cumulative temperature during growing season | Grain corn NAVI | Sanatec Seed Co., Ltd.: https://corngrain.p-e-s.co.jp/magazine/cumulative growing season temperature/
[2] [PDF] Growth and development of corn - American Grain Association: href="https://grainsjp.org/cms/wp-content/uploads/dlm_uploads/d75c7977ea1aab00b87981d147385e3d.pdf" target="_blank" rel="noopener [3] [PDF] About the Pioneer corn integrated temperature calculation program: http://phj-pioneer.com/pdf/how_to_use_2024.pdf
[4] [PDF] Hokkaido Agricultural Research Project Research Results Series No.9 : https://www.naro.go.jp/publicity_report/publication/archive/files/harcproject9.pdf
[5] [PDF] How to use very early varieties What is the appropriate harvest time for corn: http://webbook.hokuren.or.jp/bookdata/00000325/origin/page-0005.pdf
[6] [PDF] About the Pioneer corn integrated temperature calculation program Supplementary information: http://www.phj-pioneer.com/pdf/how_to_use.pdf
[7] Corn Growth Stages and GDU Requirements : https://www.corn-states.com/app/uploads/2018/07/corn-growth-stages-and-gdu-requirements.pdf
[8] [PDF] Two-season cultivation technology of corn for feed, Aichi Prefectural Agricultural Experiment Station: https://www.pref.aichi.jp/uploaded/attachment/329807.pdf
[9] Growing Degree Days (GDD) - NDAWN : https://ndawn.ndsu.nodak.edu/help-corn-growing-degree-days.html
[10] Growing Season Characteristics and Requirements in the Corn Belt - Purdue Extension : https://www.extension.purdue.edu/extmedia/nch/nch-40.html