Soil temperature conditions for vegetable seed germination

J. F. Harrington
Published April 2013, Reviewed 2024

Results of an experiment to see correlations between various vegetable seeds number of days to sprout appearance and the temperature at which they are kept.

Soil Temperature Conditions for Vegetable Seed Germination (in degrees F)1

Crop Minimum Optimum Range Optimum Maximum
Asparagus 50 60 - 85 75 95
Bean 60 60 - 85 80 95
Beet 40 50 - 85 85 95
Cabbage 40 45 - 95 85 100
Carrot 40 45 - 85 80 95
Cauliflower 40 45 - 85 80 100
Chard, Swiss 40 50 - 85 85 95
Corn 50 60 - 95 95 105
Cucumber 60 60 - 95 95 105
Eggplant 60 75 - 90 85 95
Lettuce 35 40 - 80 75 95
Muskmelon 60 75 - 95 90 100
Onion 35 50 - 95 75 95
Parsley 40 50 - 85 75 90
Parsnip 35 50 - 70 65 85
Pea 40 40 -75 75 85
Pepper 60 65 - 95 85 95
Pumpkin 60 70 - 90 95 100
Radish 40 45 - 90 85 95
Spinach 35 45 - 75 70 85
Squash 60 70 - 95 95 100
Tomato 50 60 - 85 85 95
Turnip 40 60 - 105 85 105
Watermelon 60 70 - 95 95 105

Days to Appearance of Seedlings at Various Soil Temperatures from Seed Planted at ½" Depth

Crop 32 41 50 59 68 77 86 95 104
Asparagus little or no germination little or no germination 53 24 15 10 11 19 28
Bean little or no germination little or no germination little or no germination 16 11 8 6 6 little or no germination
Beet not tested 42 17 10 6 5 4 4 not tested
Cabbage not tested not tested 15 9 6 4 3 not tested not tested
Carrot little or no germination 51 17 10 7 6 6 8 little or no germination
Cauliflower not tested not tested 19 10 6 5 4 not tested not tested
Corn little or no germination little or no germination 22 12 7 4 4 3 little or no germination
Cucumber little or no germination little or no germination little or no germination 13 6 4 3 3 not tested
Eggplant not tested not tested not tested 13 8 5 not tested not tested not tested
Lettuce 49 15 7 4 3 2 2 little or no germination little or no germination
Muskmelon not tested not tested not tested not tested 8 4 3 not tested not tested
Onion 135 31 13 7 5 4 4 12 little or no germination
Parsley not tested not tested 29 17 14 13 12 not tested not tested
Parsnip 171 57 27 19 14 15 32 little or no germination little or no germination
Pea not tested 36 13 9 7 6 6 not tested not tested
Pepper little or no germination little or no germination little or no germination 25 12 8 8 9 little or no germination
Radish not tested 29 11 6 4 3 3 not tested not tested
Spinach 62 22 12 7 6 5 6 little or no germination little or no germination
Tomato little or no germination little or no germination 43 14 8 6 6 9 little or no germination
Turnip little or no germination little or no germination 5 3 2 1 1 1 2
Watermelon not tested little or no germination not tested not tested 12 5 4 3 not tested
  • 1Daily fluctuation to 60F or lower at night is essential.

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