Optimum Soil Temperatures
For Seed Germination

It is better to sow your seeds a little late rather than too early. In the spring,  the air temperatures may be warm for a few days, but this will have little effect on the soil temperature.   Only when the days and nights both stay warm for an extended period of time will the soil temperature start to rise.

VARIETY
SOIL TEMPERATURE
DAYS TO GERMINATE
 Bean, lima
 85 degrees F
 7 to 10 days
 Bean, snap
 75 to 80 degrees F
 7 days
 Beet
 75 degrees F
 7 to 14 days
 Broccoli
 65 to 75 degrees F
 5 to 10 days
 Brussels sprout
 68 to 75 degrees F
 5 to 10 days
 Cabbage
 68 to 75 degrees F
 5 to 10 days
 Cantaloupe
 80 to 85 degrees F
 5 to 10 days
 Carrot
 75 degrees F
 12 to 15 days
 Cauliflower
 65 to 75 degrees F
 5 to 10 days
 Celery
 70 to 75 degrees F
 10 to 14 days
 Collard
 70 to 75 degrees F
 5 to 10 days
 Corn
 75 to 85 degrees F
 7-10 days
 Cucumber
 70 to 85 degrees F
 7 to 10 days
 Eggplant
 75 to 85 degrees F
 10 to 12 days
 Endive
 70 to 75 degrees F
 10 to 14 days
 Kale
 70 to 75 degrees F
 5 to 10 days
 Kohlrabi
 70 to 75 degrees F
 5 to 10 days
 Lettuce
 65 to 70 degrees F
 7 to 10 days
 Melon
 80 to 85 degrees F
 5 to 10 days
 Mustard Greens
 70 degrees F
 5 to 10 days
 Okra
 80 to 85 degrees F
7 to 14 days
 Onion, bulbing
 70 to 75 degrees F
 10 to 14 days
 Onion, bunching
 60 to 70 degrees F
 10 to 14 days
 Parsnip
70 degrees F
 14 to 21 days
 Pea
 65 to 70 degrees F
 7 to 14 days
 Pepper
 78 to 85 degrees F
 10 to 14 days
 Pumpkin
 70 to 75 degrees F
 7 to 10 days
 Radish
 65 to 70 degrees F
 5 to 7 days
 Rutabaga
 65 to 70 degrees F
 7 to 15 days
 Spinach
 70 degrees F 
 7 to 14 days
 Spinach, New Zealand
 75 degrees F
 10 to 15 days
 Squash, Summer
 75 to 85 degrees F
 7 to 14 days
 Squash, Winter
 75 to 80 degrees F
 7 to 14 days
 Swiss Chard
 70 to 75 degrees F
 7 to 14 days
 Tomato
 75 to 80 degrees F
 7 to 14 days
 Turnip
 65 to 70 degrees F
 7 to 14 days
 Watermelon
 75 to 85 degrees F
 7 to 14 days