When I first started planting my garden from seed instead of using transplants, it took me quite a few attempts to figure out the best way to get different varieties of seeds to germinate at the correct temperatures. Based on my personal research and experiences planting from seed both indoors and outdoors over the years, I have put together some easy guidelines for new and seasoned gardeners to follow.
So what temperature do seeds germinate? The optimal soil temperature for most seed varieties to germinate is around 70 degrees Fahrenheit.
While 70 degrees is the average optimal soil temperature for most seeds, any gardener would get overwhelmed with the numerous seed germination charts for different varieties of different plants in different climates (and a bunch of other factors!) out there in internet land. Read on and I will give you something easier to follow, as well as some helpful tips and guidelines to make your planting more enjoyable! Gardening is supposed to be fun, not stressful! Let’s keep it that way!
My Seed Germination Chart and Thoughts
I understand that people like to follow a simple chart when determining if the temperatures are optimal for germinating their seeds. Here is a chart I have put together by combining different sources into one table of information.
|Min Soil Temp (°F)||Best Soil Temp (°F)|
|Cool Weather Crops|
|Warm Weather Crops|
Cool weather crops are those that can generally survive a light frost. Warm weather crops are those that will be killed by a frost after germination in most cases.
This is just a short list of common vegetables as an example. Do you notice how each type of seed, whether cool season or warm season variety, will germinate at 70 degrees Fahrenheit? The number 7 is mentioned many hundreds of times in the Bible. It is God’s perfect number. Here are some examples of the number 7 in our world that God created:
- God created the universe in 6 days and rested on the 7th. (7 days in a week)
- There are 7 colors in the rainbow.
- There are 7 continents.
- Every cell in our body is replaced every 7 years.
- We are commanded to forgive not 7 times, but 7 times 70!
- A perfectly neutral soil pH is 7.
My thoughts are that by looking at plants surviving in nature without a gardener, we notice that those plants don’t need much, if any, help to grow and thrive. Man tends to try to manipulate plants and make “rules” to grow food the best way, but many times, we just mess it up anyway. When we follow what nature does in our own gardening practices, not only do we find it to be much easier, but also much less work!
In nature, plants know how to survive. This is how God made them.
Genesis 8:22: “While the earth remains, Seedtime and harvest, And cold and heat, And summer and winter, And day and night Shall not cease.”
Plants naturally attempt to self-seed. They start from a seed, grow into a plant, produce leaves and fruit, and when nature threatens their survival (too much heat, too much cold, not enough nutrients, etc.) they produce and drop their seeds to the ground, usually in the Fall. Seeds know what to do and they don’t need any help! They get naturally covered in winter from rain and snow and still manage to come up in the spring, all on their own.
Yes, there are some guidelines we can follow to ensure our seeds have the best success to germinate, but no one has time to keep track of the temperature of their soil and plant their seeds according to all these different optimal temperature ranges that you can find out on the internet.
So What Can I Do to Get My Soil Close to 70 degrees for Planting?
If you are in a climate where the ground freezes when Spring is getting close, you are undoubtedly anxious to get your garden started! For cool weather crops, many seeds can be planted as soon as the ground thaws out and can be gently worked. To help the thawing process, you can:
- Use raised beds. The soil in raised beds will thaw out faster than the soil at ground level.
- Cover your garden bed with a dark material such as a tarp or plastic for a few weeks. The sun will help heat up your soil under this dark material.
Other ways to get your seeds started at the optimal temperature is to:
- Start your seeds in mobile containers. You can move your containers outdoors in the sun during the day and put them in a shelter (indoors, garage or overhang) at night to protect them from the colder temperatures.
- Start your seeds indoors. Most home temperatures are kept at close to 70 degrees! If you have a cold basement, you can use heat mats to warm up your soil. Check out our Best Seed Starting Products page for more information on how you can get started germinating your seeds indoors!
- Keep your soil covered with mulch! This can be a great insulator from the cold and the heat! This is also the number one rule of this entire blog. Do Not Disturb your soil and always keep it covered! The health of your plants comes from all of the life that exists IN YOUR SOIL.
- Build a cold frame or low tunnel. This can give your seeds protection from the cold, much like a greenhouse.
How Do I Measure My Soil Temperature?
If you are curious about what your soil temperature is at different times of the year, you can measure the temperature by using a soil thermometer. You can follow the directions on the package, but here is the basic procedure:
- Pull back your mulch until you get to the soil. (if you aren’t using mulch at all times, you should be!)
- Push the thermometer down into the soil. For seedlings and shallow-rooted crops, 1-2 inches down is the best place to measure. If you are transplanting a more mature plant, measure the temperature 6 or more inches down.
- Leave the thermometer in the soil for a few minutes to get an accurate reading.
- Measure multiple different spots for best results.
- Measure at the same time each day to see how your soil temperature is changing. Morning is the best time to measure.
Where is the Best Place to Buy Seeds?
Temperature is not the only factor that contributes to the success of your seeds germinating. The origin and age of your seeds are also very important.
The absolute best place to get your seeds is from your own plants! Did you know if you save the seeds of your plants each year, your plants will be healthier and more resistant to disease, pests, and climate conditions in your area? Plants adapt to their surroundings and get stronger and healthier each year!
So how do you save your own seeds? First, you need to start with heirloom varieties of plants. Let your plant fully mature. If you think a plant is finished producing, do not pull it out! Wait for those seeds!
Some plants will flower, such as leafy greens, onions, and herbs. When the plant flowers, it will produce seeds. When these flowers and seed pods dry out, you can shake out the seeds and store them for next season!
When saving seeds from plants that produce fruit, such as tomatoes, peppers, cucumbers, and peas, wait until the fruit fully ripens. Then, cut open the fruit, collect the seeds, dry them out, and save them for next season. #easypeasy
A final helpful tip for saving seeds: Always save seeds from your biggest and healthiest plants and fruit. These plants will produce the best and strongest seeds and will increase your success for next year! It’s totally worth it.
Collecting your own seeds might seem like a daunting task at first, but each year it is worth a try to save some seeds from a new plant to experiment! Just know that some may work better than others. Find what works best! I am currently not saving seeds from all of my plants, but I am experimenting each year.
For plants whose seeds I do not collect, I buy them from MIgardener for 99 cents a pack! This is a great deal! What’s even better is that all of their seeds are great quality, fresh, and have high germination rates! A few other options that I’ve heard are great, but that I haven’t tried myself are Johnny Seeds, Fedco Seeds, and Eden Brothers.
Check out Our Favorite Products page to find everything you might need to help make your garden a success!
How long do seeds take to germinate? This depends on what you are planting, but with the right soil conditions, most seeds will start shooting out their first root within 48 hours or so. However, the plant may not be visible above the soil for another 3-7 days. If you don’t see your plants growing after a week, do not give up! I have had seeds take up to 14 days to germinate. The seed packet should provide information on approximate germination time.
Do seeds need light to germinate? Actually, most do not! Think about it: seeds are placed in the soil, so light isn’t really even able to reach them. The seeds can germinate and send down roots without light. The plant will start searching for light AFTER germination when the stem and leaves are poking up through the soil.