Min/Opt/Max temps from IFAS
MINIMUM Soil Temperature for Germination
- 32° – Lettuce, Onion, and Spinach
- 40° – Beet, Broccoli, Cabbage, Carrot, Cauliflower, Parsley, Pea, Radish, Swiss Chard
- 50° – Sweet Corn, Tomato
- 60° – Lima bean, Snap Bean, Cucumber, Okra, and Pepper
- 65° – Squash
OPTIMUM Soil Temperature for Germination
- 70° – Celery, Parsnip, and Spinach
- 75° – Asparagus, Endive, Lettuce, and Pea
- 80° – Lima Bean, Carrot, Cauliflower, Onion, Radish, Tomato, Turnip
- 85° – Snap Bean, Beet, Broccoli, Cabbage, Parsley, Pepper, Sweet Corn, and Swiss Chard
- 95° – Cucumber, Okra, Squash
MAXIMUM Soil Temperature for Germination
- 75° – Lettuce and Spinach
- 85° – Lima Beans, and Pea
- 95° – Snap Bean, Beet, Broccoli, Cabbage, Carrot, Cauliflower, Eggplant, Onion, Parsley, Pepper, Radish, Swiss Chard, and Tomato
- 106° – Cucumber, Okra, Squash, Sweet Corn
About Southern Peas from Clemson.edu
Southern peas are a warm-season crop requiring warm soil temperature (at least 60 °F) for the best germination and emergence. Many pests and diseases will plague Southern peas planted into cool soils. Four to six seeds per foot of row should be planted three-quarters to 1½ inches deep in rows 20 to 42 inches apart.
From Harvest to Table.com
- VEGETABLE SEED GERMINATION SPECIAL REQUIREMENTS
- SEED STARTING SPECIFIC CROPS
- VEGETABLE SEED GERMINATION TEMPERATURES – The extracted table is below. That info is also at UC Sacramento Cooperative Extension Service here.
Crop | Min Temp F | Opt Temp | Max Temp | Days to Germ. at Opt temp |
---|---|---|---|---|
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 |
Kale | 40 | 60-85 | 95 | 5-7 |
Kohlrabi | 40 | 60-95 | 105 | 5-10 |
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 |
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 |
Fall Germination vs. Soil Temps from Johnny’s Seeds
The dates in the table below were produced by a spreadsheet calculator from Johnny’s Seeds website. The calculator determines planting dates for crops to be planted outside, without additional protection, for fall harvest. All are crops that are frost-tolerant and taste great in cooler weather.
The calculator uses this formula:
Number of Days to Maturity (they used varieties recommended for fall/winter)
+ Days of Average Harvest Period
+ Fall Factor (takes into account the slowing of growth that results from cool weather and short days in fall, amounting to about 2 weeks)
= Days to Count Back from First Frost Date
The Optimum and Maximum Temperatures came from the page at this site that cites the data sources.
Based on the average first frost date of 11/30/2019 | |||
Crop | Plant NLT ** | Opt Soil Temp | Max Soil Temp |
Brussels Sprouts (TP)*** | 8/2/2019 | 65-85 | 95 |
Cabbage, storage (TP) | 8/7/2019 | 85 | 95 |
Leeks (TP) | 8/7/2019 | 75 | 95 |
Cabbage, fresh eating (TP) | 9/1/2019 | 85 | 95 |
Carrots (DS) | 9/5/2019 | 80 | 95 |
Broccoli (TP) | 9/7/2019 | 85 | 95 |
Cauliflower (TP) | 9/8/2019 | 80 | 95 |
Onions (DS) | 9/11/2019 | 80 | 95 |
Beets (DS) | 9/18/2019 | 85 | 95 |
Greens, Asian, full size (DS) | 9/23/2019 | ||
Lettuce, heads (DS) | 9/23/2019 | 75 | |
Cabbage, Chinese (TP) | 9/24/2019 | 85 | 95 |
Radish, Daikon (DS) | 9/26/2019 | 85 | |
Swiss chard, bunching (DS) | 9/27/2019 | 85 | 95 |
Lettuce, baby (DS) | 10/3/2019 | 75 | 85 |
Spinach (DS) | 10/7/2019 | 70 | 75 |
Radish, round (DS) | 10/25/2019 | 80 | 95 |
** The date calculated is the date to plant outdoors; crops that should be direct-sown are marked DS. Those marked TP should be set out as transplants on the date shown, so seeds should be started 4 weeks before the planting date.
*** Brussels sprouts should mature after frost, so no additional time is added for the harvest period or fall factor.