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

Leave a Reply

More From Gardening Calendar

How to Care and Propagate The Superb Calathea

Discover the wonderful Calathea varieties, their care and their dazzling array of colorful leaves for your landscape and indoor plant! Get to know their care, lighting, watering and fertilizing needs – as well as propagation tips – to enjoy their beauty and reap the rewards of their circadian rhythm.

Orchids at the Vallarta Botanical Garden

Stop at this month's fascinating Myrmecophila galeottiana orchid to learn about its unique relationship with ants, then explore Vallarta Botanical Garden's great diversity of other orchids!

Hügelkultur for Winter Compost

Learn about hügelkultur raised beds for composting and attracting wildlife. Improve soil fertility, water retention and provide for sustainable plant growth.