Germination temperatures

CROP Min °C. Optimum Range°C Optimum °C Max °C
Asparagus 10 15-30 24 35
Bean 15 15-30 27 35
Bean, Lima 15 18-30 30 30
Beet 5 10-30 30 35
Cabbage 5 7-35 30 38
Carrot 5 7-30 27 35
Cauliflower 5 7-30 27 38
Celery 5 15-21 21* 30*
Chard, Swiss 5 10-30 30 35
Corn 10 15-35 35 40
Cucumber 15 15-35 35 40
Eggplant 15 24-32 30 35
Lettuce 2 5-27 24 30
Muskmelon 15 24-35 32 38
Okra 15 21-35 35 40
Onion 2 10-35 24 35
Parsley 5 10-30 24 32
Parsnip 2 10-21 18 30
Pea 5 5-24 24 30
Pepper 15 18-35 30 35
Pumpkin 15 21-32 35 38
Radish 5 7-32 30 35
Spinach 2 7-24 21 30
Squash 15 21-35 35 38
Tomato 10 15-30 30 35
Turnip 5 15-40 30 40
Watermelon 15 21-35 35 40

*Daily fluctuation to 10 degrees or lower at night is essential.

From James Edward Knott, Handbook for Vegetable Growers, John Wiley& Sons, Inc., New York, 1357, p. 8. Secondary source: “How to Grow More Vegetables than you ever thought possible on less land than you can imagine”. John Jeavons, Ten Speed Press, California.