Soil and Seed Temperature Germination Chart

How do tomato or lettuce seeds know when the temperature is right for germination? Well, this question will remain unanswered for now. We just know that it’s important that seeds have the right temperatures for germination. Germination temperature usually means soil temperature. During the day, soil stores heat. At night, soil releases heat into the atmosphere.

The University of Nebraska Video included below advocates for planting when soil temperatures are 10 degrees F (about 5 degrees C) above minimum germination temperatures. This concept is supported in our chart.

Seed Temperature Germination Chart
Video – Vegetable Soil Temperatures

Seed Temperature Germination Chart

Source: Mostly from University of Oregon. Other information from other sources.

Crop	Germination Minimum Soil Temperature (°F)	Germination Optimum Soil Temperature Range (°F)	Germination Maximum Soil Temperature (°F)	Days to Germination at Optimal Temps
Asparagus	50	60-85	95	14-18
Bean, lima	60	75-85	85	4-10
Bean, snap	60	75-85	95	4-10
Beet	40	60-85	95	4-10
Broccoli	40	60-85	95	7-10
Brussels sprouts	40	60-85	95	3-10
Cabbage	40	60-85	95	5-10
Carrot	40	65-85	95	6
Cauliflower	40	65-85	95	4-10
Celery	40	60-70	95	10
Chinese cabbage	40	60-85	95	4-10
Collards	40	60-85	95	5-10
Corn	50	65-95	105	4-10
Cucumber	60	65-95	105	5-7
Eggplant	60	75-85	95	10-15
Endive/Escarole	35	60-75	85	10-14
Garlic	35	65-85	95	7-14
Kale	40	60-85	95	5-7
Kohlrabi	40	60-95	105	5-10
Leeks	35	65-85	95	8-16
Lettuce	35	60-75	85	2-10
Muskmelon	60	75-95	105	4-10
Mustard	35	60-75	85	4-6
Okra	60	85-95	105	7-12
Onion	35	65-85	95	4-12
Parsley	40	65-85	95	5-6 weeks
Parsnip	35	65-75	85	5-28
Pea	40	65-75	85	5-7
Pepper	60	65-75	95	7-10
Pumpkin	60	85-95	105	4-10
Radicchio	35	60-75	85	5-7
Radish	40	65-85	95	4-10
Spinach	35	65-75	75	6-14
Squash	60	85-95	105	7-10
Swiss chard	40	65-85	95	7
Tomato	50	65-85	95	5-7
Turnip	40	60-95	105	3-10
Watermelon	60	70-95	105	4-10