Need to understand the required soil temperature for planting vegetables in your garden? Here’s some info, plus a chart, to get you started.
Soil temperature for planting vegetables
Vegetable seeds require a number of different conditions to germinate and sprout successfully. The most critical aspects tend to be the presence of moisture and a soil temperature that’s within a defined range.
Most vegetable seeds germinate well at soil temperatures between 60°F (16°C) and 75°F (24°C). That said, some veggies like to sprout at cooler soil temperatures and some won’t sprout unless the soil is downright warm. You will need a soil thermometer to measure the approximate temperature at planting depth
Vegetable seeds sprout most quickly at their optimal germination temperature. They each usually have a comfortable optimum range for germination.
Cool-season crops (like peas, lettuce, and carrots) need to be planted early in the spring so they have enough time to grow before the weather gets hot in the summer. Warm-season crops (like tomatoes, corn, and pumpkins) run the risk of seed rot if planted too early in cold, damp soil.
Chart: Soil temperatures for planting popular vegetables
Table 1.0: Optimal soil temperature range for seed germination of popular garden vegetables in °F (US customary units)
| Vegetable seed | Low end of optimum soil temperature range (°F) | High end of optimum soil temperature range (°F) |
|---|---|---|
| Pea | 40 | 75 |
| Lettuce | 40 | 80 |
| Spinach | 45 | 75 |
| Carrot | 45 | 85 |
| Cauliflower | 45 | 85 |
| Radish | 45 | 90 |
| Cabbage | 45 | 95 |
| Beet | 50 | 85 |
| Chard | 50 | 85 |
| Onion | 50 | 95 |
| Bean | 60 | 85 |
| Tomato | 60 | 85 |
| Corn | 60 | 95 |
| Cucumber | 60 | 95 |
| Pepper | 65 | 95 |
| Pumpkin | 70 | 90 |
| Squash | 70 | 95 |
| Melon | 70 | 95 |
Reference: Knott’s Handbook for Vegetable Growers (Sixth Edition)
Chart: Soil temperatures in Celcius for planting popular vegetables
Table 2.0: Optimal soil temperature range for seed germination of popular garden vegetables in °C (metric units)
| Vegetable seed | Low end of optimum soil temperature range (°C) | High end of optimum soil temperature range (°C) |
|---|---|---|
| Pea | 4 | 24 |
| Lettuce | 4 | 27 |
| Spinach | 7 | 24 |
| Carrot | 7 | 29 |
| Cauliflower | 7 | 29 |
| Radish | 7 | 32 |
| Cabbage | 7 | 35 |
| Beet | 10 | 29 |
| Chard | 10 | 29 |
| Onion | 10 | 35 |
| Bean | 16 | 29 |
| Tomato | 16 | 29 |
| Corn | 16 | 35 |
| Cucumber | 16 | 35 |
| Pepper | 18 | 35 |
| Pumpkin | 21 | 32 |
| Squash | 21 | 35 |
| Melon | 21 | 35 |
Full charts are available in the gardening data section on the page, Vegetable seed germination charts.
