This page contains three extracts with similar info presented different ways.
Min/Opt/Max temps from IFAS
MINIMUM Soil Temperature for Germination
- 32° – Endive, Lettuce, Onion, Parsnip, and Spinach
- 40° – Beet, Broccoli, Cabbage, Carrot, Cauliflower, Parsley, Pea, Radish, Swiss Chard, and Celery
- 50° – Asparagus, Sweet Corn, Tomato, and Turnip
- 60° – Lima bean, Snap Bean, Cucumber, Okra, and Pepper
- 65° – Eggplant, Muskmelon, Pumpkin, Squash, and Watermelon
OPTIMUM Soil Temperature for Germination
- 70° – Celery, Parsnip, and Spinach
- 75° – Asparagus, Endive, Lettuce, and Pea
- 80° – Lima Bean, Carrot, Cauliflower, Onion, Radish, Tomato, Turnip
- 85° – Snap Bean, Beet, Broccoli, Cabbage, Eggplant, Parsley, Pepper, Sweet Corn, and Swiss Chard
- 95° – Cucumber, Muskmelon, Okra, Pumpkin, Squash, and Watermelon.
MAXIMUM Soil Temperature for Germination
- 75° – Celery, Endive, Lettuce, and Spinach
- 85° – Lima Beans, Parsnip, and Pea
- 95° – Asparagus, Snap Bean, Beet, Broccoli, Cabbage, Carrot, Cauliflower, Eggplant, Onion, Parsley, Pepper, Radish, Swiss Chard, and Tomato
- 106° – Cucumber, Muskmelon, Okra, Pumpkin, Squash, Sweet Corn, Turnip, and Watermelon
Garden Vegetable Seed Germination Temperatures
The soil temperature for planting vegetables should be:
- 40° F or warmer: Lettuce, kale, peas, spinach.
- 50° F or warmer: Onions, leeks, turnips, Swiss chard.
- 60° F or warmer: Broccoli, cabbage, cauliflower, carrots, beans, beets.
- 70° F or warmer: Tomatoes, squash, corn, cucumbers, melons, peppers.
The location of the black dot indicates the optimum germination temperatures (according to the University of California at Davis). The green dot is the “realistic” soil temperatures that Dr. Parsons recommends to ensure good germination in the garden. For practical purposes, you can start planting as soon as the soil reaches this temperature.
Real-time soil temperature national map – https://www.agweb.com/weather/soil-temperatures