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

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

Our dilemma of germination temperatures of tomato or lettuce seeds is answered, as well as for many other vegetable gemination temperatures.

Video – Vegetable Soil Temperatures