Last Updated on April 29, 2024
Vegetable Seed Germination Temperature Chart
Why Use Vegetable Seed Germination Temperature Chart?
There are a number of reasons why you should use a vegetable seed germination temperature chart when starting your seeds.
First, it can help you determine the optimum temperature for germinating your particular type of seed. This is important because different seeds have different temperature requirements for germination.
Second, a germination temperature chart can help you troubleshoot problems with your seed germination. If you are having trouble getting your seeds to germinate, a chart can help you identify the problem.
Third, a germination temperature chart can help you plan your gardening schedule. By knowing the optimum temperature for germinating your seeds, you can plan when to start your seeds so that they will be ready to plant when the weather is right.
Finally, a germination temperature chart can help you save money. By starting your seeds at the optimum temperature, you can avoid having to buy new seeds every year.
How to Use Our Vegetable Seed Germination Temperature Chart
The below vegetable seed germination temperature chart shows the optional temperatures that seeds germinate. Don’t forget to bookmark this page! If you are like me, you’ll want to reference it again!
- The first vegetable seed germination temperature chart shows optional temperatures for each vegetable.
- The second vegetable seed germination temperature chart shows germination times in days for each vegetable at different soil temperatures.
Seeds are designed to germinate at different temperatures!
For example, Spinach is a cool-weather crop. Looking at the vegetable seed germination temperature chart below, Spinach will start germination in early spring in cool weather starting at 32-40F.
Warm-weather crops like Tomatoes would not germinate at these low temperatures.
How Can This Vegetable Seed Germination Temperature Chart Help When Starting Seeds?
When starting seeds indoors you should try to keep them at the optional temperature listed in the vegetable seed germination temperature chart below.
When sowing seeds outdoors in the garden you can use this as a reference to know when best to sow seeds. Don’t worry if you sow too early into the garden, once the soil warms up the warmer weather seeds will germinate.
To find out the best time to start plants indoors or outdoors for your location, don’t forget to check out our plan my garden tool to get your custom garden plan in minutes.
Optimal Soil Temperature For Vegetable Seed Germination
| Crops | Minimum (°F) | Optimum range (°F) | Maximum (°F) |
|---|---|---|---|
| Asparagus | 50 | 75-85 | 95 |
| Beans, Lima | 60 | 75-85 | 85 |
| Beans, Snap | 60 | 75-85 | 95 |
| Beets | 40 | 65-85 | 95 |
| Broccoli | 40 | 60-85 | 95 |
| Cabbage | 40 | 60-85 | 95 |
| Carrots | 40 | 65-85 | 95 |
| Cauliflower | 40 | 65-85 | 95 |
| Celery | 40 | * | * |
| Chard, Swiss | 40 | 65-85 | 95 |
| Corn | 50 | 65-95 | 105 |
| Cucumbers | 60 | 65-95 | 105 |
| Eggplant | 60 | 75-85 | 95 |
| Garlic | 32 | 65-85 | 95 |
| Leeks | 32 | 65-85 | 95 |
| Lettuce | 32 | 60-75 | 85 |
| Muskmelons (Cantaloupe) | 60 | 75-85 | 105 |
| Okra | 60 | 85-95 | 105 |
| Onions | 32 | 65-85 | 95 |
| Parsley | 40 | 65-85 | 95 |
| Parsnips | 32 | 65-75 | 85 |
| Peas | 40 | 65-75 | 85 |
| Peppers | 60 | 65-75 | 95 |
| Pumpkins | 60 | 85-95 | 105 |
| Radishes | 40 | 65-85 | 95 |
| Spinach | 32 | 65-75 | 75 |
| Squash | 60 | 85-95 | 105 |
| Tomatoes | 50 | 65-85 | 95 |
| Turnips | 40 | 60-95 | 105 |
| Watermelons | 60 | 75-95 | 105 |
Source: California Master Gardener Handbook, 2nd edition, Regents of the University of California, Division of Agriculture and Natural Resources, Publication 3382 (Table 5.2, page 114).
*Note: Celery requires diffuse light and a night temperature from 10° to 15°F lower than the day temperature for good germination. Optimal conditions are 85°F day, 70°F night with diffuse light and high moisture.
Number of Days for Vegetable Seedlings to Emerge At Different Soil Temperatures
| Crops | 32°F | 41°F | 50°F | 59°F | 68°F | 77°F | 86°F | 95°F | 104°F |
|---|---|---|---|---|---|---|---|---|---|
| Asparagus | 0.0 | 0.0 | 52.8 | 24.0 | 14.6 | 10.3 | 11.5 | 19.3 | 28.4 |
| Beans, Lima | — | — | 0.0 | 30.5 | 17.6 | 6.5 | 6.7 | 0.0 | — |
| Beans, Snap | 0.0 | 0.0 | 0.0 | 16.1 | 11.4 | 8.1 | 6.4 | 6.2 | 0.0 |
| Beets | — | 42.0 | 16.7 | 9.7 | 6.2 | 5.0 | 4.5 | 4.6 | — |
| Cabbage | — | — | 14.6 | 8.7 | 5.8 | 4.5 | 3.5 | — | — |
| Carrots | 0.0 | 50.6 | 17.3 | 10.1 | 6.9 | 6.2 | 6.0 | 8.6 | 0.0 |
| Cauliflower | — | — | 19.5 | 9.9 | 6.2 | 5.2 | 4.7 | — | — |
| Celery | 0.0 | 41.0 | 16.0 | 12.0 | 7.0 | 0.0 | 0.0 | 0.0 | — |
| Corn, Sweet | 0.0 | 0.0 | 21.6 | 12.4 | 6.9 | 4.0 | 3.7 | 3.4 | 0.0 |
| Cucumbers | 0.0 | 0.0 | 0.0 | 13.0 | 6.2 | 4.0 | 3.1 | 3.0 | — |
| Eggplant | 0.0 | — | — | — | 13.1 | 8.1 | 5.3 | — | — |
| Lettuce | 49.0 | 14.9 | 7.0 | 3.9 | 2.6 | 2.2 | 2.6 | 0.0 | 0.0 |
| Muskmelons | — | — | — | — | 8.4 | 4.0 | 3.1 | — | — |
| Okra | 0.0 | 0.0 | 0.0 | 27.2 | 17.4 | 12.5 | 6.8 | 6.4 | 6.7 |
| Onions | 135.8 | 30.6 | 13.4 | 7.1 | 4.6 | 3.6 | 3.9 | 12.5 | 0.0 |
| Parsley | — | — | 29.0 | 17.0 | 14.0 | 13.0 | 12.3 | — | — |
| Parsnips | 171.7 | 56.7 | 26.6 | 19.3 | 13.6 | 14.9 | 31.6 | 0.0 | 0.0 |
| Peas | — | 36.0 | 13.5 | 9.4 | 7.5 | 6.2 | 5.9 | — | — |
| Peppers | 0.0 | 0.0 | 0.0 | 25.0 | 12.5 | 8.4 | 7.6 | 8.8 | 0.0 |
| Radishes | 0.0 | 29.0 | 11.2 | 6.3 | 4.2 | 3.5 | 3.0 | — | — |
| Spinach | 62.6 | 22.5 | 11.7 | 6.9 | 5.7 | 5.1 | 6.4 | 0.0 | 0.0 |
| Tomatoes | 0.0 | 0.0 | 42.9 | 13.6 | 8.2 | 5.9 | 5.9 | 9.2 | 0.0 |
| Turnips | 0.0 | 0.0 | 5.2 | 3.0 | 1.9 | 1.4 | 1.1 | 1.2 | 2.5 |
| Watermelons | — | 0.0 | — | — | 11.8 | 4.7 | 3.5 | 3.0 | — |
Sources: J.F. Harrington, Department of Vegetable Crops, University of California, Davis, Agricultural Extension Leaflet, 1954 “The New Seed-Starting Handbook”, Nancy Bubel, 1988, Rodale Press Notes: 0.00 = little or no germination — = not tested
How Can I Control My Vegetable Seed Germination Temperature When Starting Plants?
Seedling Heat Mats for plants is a great way to accurately control the temperature of seed trays during the germination period. Seedling heat mats with a thermostat can be used to precisely control soil temperature.
If you have ever started your own plants from seed, you know that getting them to germinate can sometimes be a challenge. One way to improve your success rate is to use a seedling heat mat. A seedling heat mat is a special mat that is placed under your planting tray or pots. It emits heat which helps to encourage seed germination.
There are a few reasons why you might want to use a seedling heat mat. First, it can help you to achieve a higher germination rate. This is especially helpful if you are starting your seeds early in the season when it is still cold outside. The extra heat from the mat can make all the difference in whether your seeds germinate or not.
Another reason to use a seedling heat mat is that it can help your plants to grow faster and healthier. The extra heat helps the roots to grow more quickly, which results in healthier, stronger plants. If you are trying to grow plants quickly for a particular reason, such as starting your garden early in the season, a heat mat can be a big help.
Using a seed heat mat will increase germination times when set to the optimal temperatures listed above. HossTools has great heat mats and controllers at a reasonable price.
A Dome Tray Helps Retain Moisture – Increasing Germination Rates
Seedlings need to be kept moist, but not too wet, in order to germinate properly. By using a dome over your seedling tray, you can help to maintain a more consistent level of moisture, which can lead to higher germination rates.
Domes also help to protect seedlings from drafts, which can dry them out and prevent them from germinating.
If you don’t have a dome to place over your seed tray, you can alternatively use saran wrap. However, make sure to remove or unwrap them as soon as the seedlings germinate. Here is a selection of domed trays from Hoss tools.
What is a Soil Temperature Thermometer?
A soil thermometer is a useful tool for gardeners that allows you to measure the temperature of your soil.
This can be helpful for determining the best time to plant seeds or transplant seedlings, as well as monitoring the temperature of your soil throughout the growing season.
Most plants prefer soil temperatures between 60-70°F for optimal growth, so using a soil thermometer can help you ensure that your soil is at the right temperature for your plants to thrive.
There are two main types of soil thermometers: digital and analog.
- Digital thermometers tend to be easier to read but they may require batteries or other power sources.
- Analog thermometers, on the other hand, do not require any additional power and can be a good choice for those who prefer a more traditional tool.
If you’re in the market for a soil thermometer, the AcuRite 00661 Stainless Steel Soil Thermometer, which has received excellent reviews on Amazon, is a good option to consider.
Frequently Asked Vegetable Seed Germination Temperature Chart Questions
The optimum temperature range for tomatoes is 65° to 85°F. Within that range, it takes approximately 6 to 8 days before seeds germinate. Tomato seeds may still germinate at 50°F, but it will take over 40 days, and there will probably be no germination if the soil temperature is 104°F
The optimum temperature range for Lima beans is 75° to 85°F, within which it takes approximately 6.5 days for seeds to germinate. Lima bean seeds may still germinate at 59°F, but it will take around 30.5 days, and there will probably be no germination if the soil temperature is 95°F.
The optimum temperature range for snap beans is 75° to 85°F. Within that range, it takes approximately 8.1 days before seeds germinate. Snap bean seeds may still germinate at 59°F, but it will take over 16.1 days, and there will probably be no germination if the soil temperature is 104°F.
The optimum temperature range for beet seeds is 65° to 85°F. Within that range, it takes approximately 5 to 6.2 days before seeds germinate. Beet seeds may still germinate at 41°F, but it will take over 42 days, and there will probably be no germination if the soil temperature is 104°F.
The optimum temperature range for pea seeds to germinate is 65° to 75°F. Within this range, it takes approximately 7 to 6 days for pea seeds to germinate. Pea seeds may still germinate at temperatures as low as 40°F, but it will take about 36 days, and there is no data available on the effect of temperatures higher than 95°F on pea seed germination.
The optimum temperature range for pepper seeds to germinate is 65° to 75°F. Within this range, it takes approximately 8 to 12 days for pepper seeds to germinate. Pepper seeds may still germinate at temperatures as low as 60°F, but it will take about 25 days, and there will probably be no germination if the soil temperature is 104°F.
The optimum temperature range for corn seeds to germinate is 65° to 95°F. Within this range, it takes approximately 6 to 8 days for corn seeds to germinate. Corn seeds may still germinate at temperatures as low as 50°F, but it will take over 21 days, and there will probably be no germination if the soil temperature is 105°F.
The optimum temperature range for cucumber seeds to germinate is 65° to 95°F. Within this range, it takes approximately 4 to 6 days for cucumber seeds to germinate. Cucumber seeds may still germinate at temperatures as low as 60°F, but it will take over 13 days, and there will probably be no germination if the soil temperature is 105°F.
The optimum temperature range for eggplant seeds to germinate is 75° to 85°F. Within this range, it takes approximately 8 to 5 days for eggplant seeds to germinate. Eggplant seeds may still germinate at temperatures as low as 68°F, but it will take about 13 days, and there is no data available on the effect of temperatures higher than 86F on eggplant seed germination.
The optimum temperature range for lettuce seeds to germinate is 60° to 75°F. Within this range, it takes approximately 3 to 2 days for lettuce seeds to germinate. Lettuce seeds may still germinate at temperatures as low as 32°F, but it will take over 49 days, and there will probably be no germination if the soil temperature is 95°F.
The optimum temperature range for muskmelon (cantaloupe) seeds to germinate is 75° to 85°F. Within this range, it takes approximately 4 to 3 days for muskmelon seeds to germinate. Muskmelon seeds may still germinate at temperatures as low as 60°F, but it will take an unknown amount of time and there is no data available on the effect of temperatures higher than 105°F on muskmelon seed germination.
The optimum temperature range for okra seeds to germinate is 85° to 95°F. Within this range, it takes approximately 6.8 to 6.4 days for okra seeds to germinate. Okra seeds may still germinate at temperatures as low as 60°F, but it will take about 27 days, and about 6.7 days at 105 °F.
The optimum temperature range for onion seeds to germinate is 65° to 85°F. Within this range, it takes approximately 3 to 4 days for onion seeds to germinate. Onion seeds may still germinate at temperatures as low as 32°F, but it will take over 135 days, and 13 days at 95°F.
The optimum temperature range for parsley seeds to germinate is 65° to 85°F. Within this range, it takes approximately 14 to 13 days for parsley seeds to germinate. Parsley seeds may still germinate at temperatures as low as 40°F, but it will take over 29 days, and there is no data available on the effect of temperatures higher than 95°F on parsley seed germination.
The optimum temperature range for parsnip seeds to germinate is 65° to 75°F. Within this range, it takes approximately 13 to 19 days for parsnip seeds to germinate. Parsnip seeds may still germinate at temperatures as low as 32°F, but it will take over 171 days, and there will probably be no germination if the soil temperature is 95°F.
The optimum temperature range for spinach seeds to germinate is 65° to 75°F. Within this range, it takes approximately 6 to 5 days for spinach seeds to germinate. Spinach seeds may still germinate at temperatures as low as 32°F, but it will take over 62 days, and there will probably be no germination if the soil temperature is 95°F.
The optimum temperature range for turnip seeds to germinate is 60° to 95°F. Within this range, it takes approximately 1 to 2 days for turnip seeds to germinate. Turnip seeds may still germinate at temperatures as low as 40°F, but it will take over 5 days.
The optimum temperature range for watermelon seeds to germinate is 75° to 95°F. Within this range, it takes approximately 4 to 3 days for watermelon seeds to germinate. Watermelon seeds may still germinate at temperatures as low as 60°F, but it will take about 11 days.
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