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.

CropGermination
Minimum Soil
Temperature (°F)
Germination
Optimum Soil
Temperature
Range (°F)
Germination
Maximum Soil
Temperature (°F)
Days to
Germination
at Optimal
Temps
Asparagus5060-859514-18
Bean, lima6075-85854-10
Bean, snap6075-85954-10
Beet4060-85954-10
Broccoli4060-85957-10
Brussels sprouts4060-85953-10
Cabbage4060-85955-10
Carrot4065-85956
Cauliflower4065-85954-10
Celery4060-709510
Chinese cabbage4060-85954-10
Collards4060-85955-10
Corn5065-951054-10
Cucumber6065-951055-7
Eggplant6075-859510-15
Endive/Escarole3560-758510-14
Garlic3565-85957-14
Kale4060-85955-7
Kohlrabi4060-951055-10
Leeks3565-85958-16
Lettuce3560-75852-10
Muskmelon6075-951054-10
Mustard3560-75854-6
Okra6085-951057-12
Onion3565-85954-12
Parsley4065-85955-6 weeks
Parsnip3565-75855-28
Pea4065-75855-7
Pepper6065-75957-10
Pumpkin6085-951054-10
Radicchio3560-75855-7
Radish4065-85954-10
Spinach3565-75756-14
Squash6085-951057-10
Swiss chard4065-85957
Tomato5065-85955-7
Turnip4060-951053-10
Watermelon6070-951054-10

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

Comments

Subscribe
Notify of
0 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments

More From Gardening Calendar

Seed Germination Tips

Starting seeds, the first thing that you should see is a pair of leaves. These are seed leaves and almost every seed will start out this way.

Join a Horticultural Society

Join a horticultural society to meet other gardeners, learn how to prepare your fairy garden for winter, and find out what to do with damaged pots! Get useful tips for keeping your garden alive and beautiful during the winter months and make sure your plants are in top shape for spring.