Summary of temperature requirements for each growth stage of green pepper (Capsicum annuum)

Overview

This report defines the main growth stages of green pepper (germination, seedling raising, cultivation/growth, flowering, fruiting/enlargement, maturity/coloring) and their respective temperature requirements (optimal_min, optimal_max, base_temperature, low_stress_threshold, high_stress_threshold, max_temperature, frost_threshold (including sterility_risk_threshold during the flowering period) is comprehensively organized based mainly on Japanese public institutions and academic materials. Also note the variations in values ​​due to differences in production sites, variety characteristics, cultivation methods (open-air/household), and climate zones. If there are undisclosed values, clearly state that fact.

Definition of each growth stage

• Germination period (germination period): From sowing until hypocotyls and cotyledons appear on the soil surface.
• Seedling-raising period (seedling-raising period): From germination to the development of healthy seedlings with several true leaves and the stage just before planting.
• Growth (cultivation) period (growing season): From after planting to first flowering. Elongation and development of leaves, stems, and roots.
• Flowering period (flowering period): The period from the first flowering to the peak of the flowering wave. An important period when the reproductive organs of pollen and pistil mature.
• Fruit-setting/enlargement stage (fruit-setting/enlargement stage): From the establishment of fruit through pollination and fertilization to rapid enlargement and internal development.
• Maturity/coloring period (ripening/coloring period): From the physiological maturity of the fruit to the completion of ripening (usually harvested 30-40 days after flowering).
• *In this report, each stage will be organized using the above definitions.

List of temperature requirements by growth stage

1. Germination stage

• optimal_min / optimal_max: 28-30°C is optimal (especially soil temperature) [1][2][3][4]
• base_temperature: Not specified in Japanese literature
• low_stress_threshold: Germination rate decreases if germination is uniform below 25°C [4]
• high_stress_threshold: 35°C The above is not recommended but not specified
• max_temperature: Not specified
• frost_threshold: Not applicable (stops germination/impossible)
• Regional differences/varietal differences: There are almost no differences between prefectures or climate regions, common management nationwide [2][4]

2. Seedling period

• optimal_min / optimal_max: Daytime 25-28°C / Nighttime 15-20°C (Soil daytime 28-30°C) [1][2][4]
• base_temperature: Base temperature at seedling-raising stage is not specified
• low_stress_threshold: At night below 10°C, growth is suppressed and disease occurrence increases [21]
• high_stress_threshold: Stress is mentioned at over 32°C but no quantitative value [2][4]
• max_temperature: Not specified
• frost_threshold: 10°C Be careful, there is no clear "lethal point" [21][3]
• Regional differences: In cold regions, raising seedlings in greenhouses and tunnels is common [3]

3. Growing (Cultivation) Stage

• optimal_min / optimal_max: Daytime 25-30°C /Night 17-23°C (both 27-28°C/18-20°C) [3][5]
• base_temperature: Base temperature not specified
• lo w_stress_threshold: Growth is suppressed at temperatures below 18°C during the day and below 15°C at night [21][5]
• high_stress_threshold: Growth failure at daytime temperatures exceeding 35°C (quantitative values not specified) [3]
• max_temperature: Not specified
• frost_threshold< /strong>: Planting safety area → minimum temperature 10°C or higher, soil temperature 15°C or higher [21][3]
• Regional differences/varietal differences: Slightly increased cold tolerance for varieties destined for Hokkaido

4. Flowering period

• optimal_min / optimal_max: 20-30°C (especially for pollen germination and fertilization) [7]
• base_temperature: Not specified
• low_stress_threshold: Pollen sterility and poor fruit set occur below 15°C [7]
• high_stress_threshold: Pollen sterility and flower drop increase above 30°C [7]
• max_temperature: Absolute lethal point not specified (fruit set failure increases above 30°C)
• f rost_threshold: Not specified (however, flowers basically die due to frost damage)
• sterility_risk_threshold: Below 15°C or above 30°C is the sterility risk range [7]
• Regional/cultivar differences: Generally common throughout the country [7]

5. Fruiting and enlargement period

• optimal_min / optimal_max: Daily average 20-28°C[16][3][4][21]
• base_temperature: Not specified
• low_stress_threshold: Poor hypertrophy and malformed fruit below 15°C [7][16]
• high_stress_threshold: 30° Above C, malformation, fruit drop, and hypertrophy occur [7][19]
• max_temperature: Above 35°C, caution is required (no quantification) [3]
• frost_th reshold: Quality deteriorates below 10°C (fruit/embryonic) [3][16]
• Regional differences: Lower limit varies slightly depending on variety characteristics, but practical range is common

6. Maturity/Coloration stage

• optimal_min / optimal_max: 20-25°C (optimal for coloring, 10°C for storage) [8]
• base_temperature: Not specified
• low_stress_threshold: Delays ripening below 15°C
• high_stress_threshold: Delays pericarp coloring above 30°C (internal ripening Possible) [8][19]
• max_temperature: Slow color of pericarp at 30°C or higher [8][19]
• frost_threshold: Below 10°C is outside the optimal storage temperature range [3]
• Notes: 10°C after harvest, Can be stored for more than 15 days at RH80% [3]

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Parameter not specified/Unpublished item

• "base_temperature" is not quantitatively specified in Japanese literature for the main stages (growth, flowering, enlargement, coloring).
• There is no clear value setting for "max_temperature (lethal temperature)" at each stage.
• The "frost_threshold (fatal limit for freezing damage)" is also said to be "be careful below 10°C", but it is not an absolute dead point setting.

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Variation by region/document

• The optimum value is within a range of ±1 to 3°C between major producing prefectures, climate zones, and technical guidance, but there is no significant difference.
• In cold regions, adjust the seedling raising period or use cold-resistant seeds. The management temperature targets themselves are generally the same nationwide.
• The only difference in management between greenhouses and open fields is the temperature control method; the optimal temperature target remains the same.

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Temperature parameter list by growth stage

Growth stage	optimal_min	optimal_max	base_temperature	low_stress_threshold	high_stress_threshold	max_t emperature	frost_threshold	sterility_risk_threshold (flowering period only)	References
Germination period	28°C	30°C	—	25°C Less than	35°C Super	—	—	—	[1][2][3][4]
Seedling growing period	25°C (daytime)	28°C (daytime)	—	10°C Less than (night)	32°C More than	—	10°C Less than	—	[1][2][4]
Growing season	25°C (daytime)	30°C (daytime)	—	Less than 18°C (daytime)	35°C Super (temporary)	—	Less than 10°C	—	[3][5]
Flowering period	20°C	30°C	—	15°C Less than	30°C More than	—	—	<15°C or >30°C	[7]
Fruiting and thickening period	20°C	28°C	—	Less than 15°C	Over 30°C	35°C Ultra	Less than 10°C	—	[3][5]
Maturity/coloring stage	20°C	25°C	—	Less than 15°C	Over 30°C	Over 30°C	10°C Less	—	[8]

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Try it in your region

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References

[1] Is it difficult to control the temperature when raising and cultivating green peppers? What should I be careful about? : https://yuime.jp/post/bigin-green-pepper-cultivation-temperature
[2] Guidelines for the optimum temperature for germination and seedling-raising temperature (suitable growth temperature) for main fruits and vegetables - Nagano Prefecture: https://www.pref.nagano.lg.jp/sakuchi/nosei-aec/joho/gijutsu/documents/kasai-ondo.pdf
[3] Cultivation of green pepper: https://www.hidefmc.com/piman/
[4] [Green pepper seedling breeding] Aim for 100% germination rate! Cultivation methods and temperature control...: https://minorasu.basf.co.jp/80754
[5] Key points of the work system for forced green pepper cultivation - Everyone's Agriculture Plaza: https://www.jeinou.com/benri/vegetable/2013/10/221000.html
[7] Green Report - JA Zennoh: https://www.zennoh.or.jp/greenreport/pdf/676/gr676_202510.pdf
[8] Regarding promotion of coloring of colored bell pepper fruits harvested during the chromophore season Factors ...: https://agriknowledge.affrc.go.jp/RN/2010872187.pdf
[16] Varieties and physiological and ecological characteristics of colored bell pepper (paprika): https://www.pref.kanagawa.jp/documents/27252/531907.pdf
[19] Green Report - JA Zennoh: https://www.zennoh.or.jp/greenreport/pdf/676/gr676_202510.pdf
[21] Green pepper - Vegetable cultivation manual | Search - Takii seeds: https://www.takii.co.jp/tsk/manual/piman.html

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Sources

[1] Is it difficult to control the temperature when raising and cultivating peppers? What should I be careful about? : https://yuime.jp/post/bigin-green-pepper-cultivation-temperature
[2] Guidelines for the optimum temperature for germination and seedling-raising temperature (suitable growth temperature) for main fruits and vegetables - Nagano Prefecture: https://www.pref.nagano.lg.jp/sakuchi/nosei-aec/joho/gijutsu/documents/kasai-ondo.pdf
[3] Cultivation of green pepper: https://www.hidefmc.com/piman/
[4] [Green pepper seedling breeding] Aim for 100% germination rate! Cultivation methods and temperature control...: https://minorasu.basf.co.jp/80754
[5] Key points of the work system for forced green pepper cultivation - Everyone's Agriculture Plaza: https://www.jeinou.com/benri/vegetable/2013/10/221000.html
[7] Green Report - JA Zennoh: https://www.zennoh.or.jp/greenreport/pdf/676/gr676_202510.pdf
[8] Regarding promotion of coloring of colored bell pepper fruits harvested during the chromophore season Factors ...: https://agriknowledge.affrc.go.jp/RN/2010872187.pdf
[16] Varieties and physiological and ecological characteristics of colored bell pepper (paprika): https://www.pref.kanagawa.jp/documents/27252/531907.pdf
[19] Green Report - JA Zennoh: https://www.zennoh.or.jp/greenreport/pdf/676/gr676_202510.pdf
[21] Green pepper - Vegetable cultivation manual | Search - Takii seeds: https://www.takii.co.jp/tsk/manual/piman.html