Soil Temperature For Vegetable & Herb Seed Germination

Soil temperature is one of the most important factors in seed germination. Too cold or too hot and the seeds may not germinate. Seeds are dormant, and germination occurs when outside factors are optimal for the plant’s survival. When the time is right, the seed germinates. Knowing the preferred soil temperature for common vegetables and herbs will increase the germination rate.

The gardener should be familiar with the requirements of each type of seed. Some require cold stratification, or seed scarification to mimic what would happen to the seed in its natural environment. Most garden centres sell soil thermometers for gardeners to monitor soil temperature.

Celsius

Fahrenheit

Anise16-1860-65
Arnica16-2160-70
Artichoke20-2170-80
Asparagus16-2960-85
Basil18-3064-86
Beetroot7-2545-77
Bergamot16-2160-70
Bok choy24-2975-85
Borage18-2165-70
Broad beans15-2559-77
Broccoli16-2960-85
Brussels sprouts7-2945-85
Cabbage7-3545-95
Calendula16-1860-65
Capsicum (pepper)21-3218-35
Caraway18-2165-70
Carrots7-2945-85
Cauliflower12-2655-80
Celery16-2160-70
Chervil12-1855-65
Chilli22-2671-79
Chives16-2160-70
Cicely12-1855-65
Collards24-2975-85
Comfrey20-2668-80
Coriander15-2259-71
Corn16-3560-95
Cucumber16-2460-95
Dill16-2160-70
Eggplant (aubergine)24-3275-90
Endive15-2559-77
Fennel16-2460-75
Kale16-2960-85
Leek16-2960-85
Lemongrass20-2368-75
Lettuce16-2360-75
Melons24-3575-95
Mint12-1855-65
Mustard12-1855-65
Okra29-3585-95
Onion10-3550-95
Oregano18-2165-70
Parsley21-2670-80
Parsnip10-2150-85
Peas4-2440-75
Pumpkin21-3270-90
Radicchio16-2460-75
Radish7-3245-90
Rocket15-2059-68
Rosemary27-3280-90
Sage15-2160-70
Spaghetti squash15-1860-65
Spinach7-2445-75
Spring onion20-3568-77
Squash21-3270-90
Swedes7-2545-77
Thyme15-2459-75
Tomato21-3570-95
Turnip7-2945-85
Watermelon21-3270-90
Zucchini (courgette)25-3568-95