It is frustrating when pepper seeds germinate slowly (or not at all), especially after waiting all winter to start your garden. However, there is usually a reason for delayed sprouting of pepper seeds.
So, why are your pepper seeds not germinating? Pepper seeds germinate slowly (or not at all) if temperatures are below 60 degrees Fahrenheit (16 degrees Celsius). Pepper seeds will also fail to germinate if they dry out. Pepper seeds that are more than 2 years old may germinate poorly (or not at all). Some hotter varieties of peppers can take a few weeks to germinate, so be patient if you think the temperature and moisture levels are correct.
Of course, there are steps you can take to ensure that you get a higher germination rate and faster seed germination for your peppers.
In this article, we’ll take a closer look at why pepper seeds fail to germinate and why they germinate slowly. We’ll also discuss how to speed up pepper seed germination, along with ways to help your pepper plants grow better once they have germinated.
Let’s get started.
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Why Are Your Pepper Seeds Not Germinating?
There are a few different reasons that pepper seeds will fail to germinate. Pepper seeds need the proper conditions to germinate, including soil temperature and moisture.
Some of the most common reasons that pepper seeds fail to germinate are:
- Improper Soil Temperature (soil is too cold or too hot)
- Improper Watering (soil is too dry or too wet)
- Old Seeds (germination rate decreases as seeds get older)
Improper Soil Temperature
As mentioned earlier, pepper seeds will fail to germinate if temperatures get too low. Soil temperatures lower than 60 degrees Fahrenheit (16 degrees Celsius) will slow down germination or prevent it entirely.
Any seeds that manage to germinate at lower temperatures may develop into smaller, weaker plants. (This is more likely if temperatures stay below 60 degrees Fahrenheit.)
Seedling heat mats are one way to keep pepper seeds warmer for germination.
You can learn about how to keep seeds warm in my article here.
You can also learn more about the coldest temperatures pepper plants can tolerate (and how to protect them from cold) in my article here.
Extreme heat can also prevent pepper seeds from germinating. Soil temperatures higher than 95 degrees Fahrenheit (35 degrees Celsius) will slow down or stop germination.
Soil can become too warm if pepper seeds are left under grow lights that give off lots of heat. Remember that pepper seeds do not need light to germinate, so you can keep the grow lights off until after they sprout.
Pepper seeds prefer a soil temperature of 65 to 75 degrees Fahrenheit (18 to 24 degrees Celsius) for ideal germination.
The table below gives the temperature ranges for pepper seed germination.
| Temp | Temp (degrees F) | Temp (degrees C) |
|---|---|---|
| Min | 60 | 16 |
| Ideal | 65 to75 | 18 to 24 |
| Max | 95 | 35 |
temperatures for pepper seed germination.
High soil temperature can also be a danger to seed germination if it causes the seeds to dry out. This is a bigger problem in dry conditions without proper watering.
Improper Watering
Pepper seeds will fail to germinate if the soil is too dry or too wet.
Seeds need contact with moist soil to tell them that there is enough water for them to survive after sprouting.
Even short periods of drying out can harm or kill pepper seeds – they are sensitive to drought in their early stages.
On the other hand, soil that is too wet (soggy) will also cause problems for germination. Seeds need air in the soil, and wet soil has less space for air.
Wet soil also increases the chances of mold growth, both before and after seed germination.
To get the right balance for soil moisture, it may help to use a spray bottle (plant mister). That way, you can add just a little bit of water where it is needed.
You can also water seed trays from below with a 2nd container holding the seed tray.
Another good option is to use a humidity dome to help keep the soil and air moist for pepper seeds. As an added benefit, a humidity dome will act like a mini greenhouse, trapping heat and keeping seeds warmer than the surrounding air.
For more information, check out my article on humidity domes.
Old Seeds
Old pepper seeds may fail to germinate at all. According to Johnny’s Selected Seeds, pepper seeds can last 2 to 5 years in storage under favorable conditions.
If the seeds do germinate, it will be at lower rates than new pepper seeds.
For more information, check out my article on how long seeds last.
Peppers seeds can germinate without light. However, seedlings will need light to grow.
So, transplant your pepper seedlings into soil where they will get plenty of sun. If you are growing them indoors, put them near a window or under a grow light.
Most pepper seeds will take between 1 to 3 weeks to germinate, depending on temperature, moisture, and age of the seeds. Also, remember that hotter varieties will generally take longer to germinate.
Why To Start Pepper Seeds Indoors
Starting your pepper seeds indoors at an early date will help you to achieve better germinate rates. Why not wait until temperatures rise and the soil outside gets warmer?
The answer is that late spring frosts or early fall frosts can cut your growing season short. This is a bigger problem in northern climates where growing seasons are already short.
Late spring frosts can stunt or kill pepper seeds or seedlings, while early fall frosts can damage or destroy mature pepper plants and their fruit.
For more information, check out this tool from the Old Farmer’s Almanac on frost dates by zip code.
Once you know the last spring frost dates for your location, you can work backwards to find your indoor planting date.
The University of Minnesota Extension suggests starting pepper seeds indoors 8 weeks before transplanting outside. This will allow you to get a longer growing season without risking loss of your seeds or plants to frost.
The question is: when to transplant pepper seeds outside? Generally, you will want to wait until 4 weeks after the last spring frost date to transplant pepper seedlings outside.
That means starting seeds indoors 4 weeks before the last spring frost date (for a total of 8 weeks from planted seed to transplant).
For example, let’s say that I want to start pepper seeds indoors in Boston, Massachusetts. The last spring frost date is April 10.
Working backwards 4 weeks (28 days) from April 10, I find that I should start pepper seeds indoors on March 13 (18 days in March + 10 days in April = 28 days).
Working forwards 4 weeks (28 days) from April 10, I find that I should transplant my pepper seedlings outdoors on May 8 (20 days in April + 8 days in May = 28 days).
You can start pepper seeds indoors in a seed tray, found online or at garden centers. You can also use flat, shallow containers such as ones you might find at the grocery store.
Once your pepper seeds germinate and grow into seedlings, you can think about transplanting them outdoors (provided the danger of frost has passed!)
Wait until nighttime temperatures are over 60 degrees Fahrenheit (16 degrees Celsius) before you put pepper plants outside.
However, if your pepper plants are still small, you can plant them in the soil and cover each one with a cloche. A cloche is a small plastic or glass container that keeps plants warm.
It can also help to protect them from pests and wind. When pepper plants get larger, you can use row covers to protect them from the cold.
Another alternative is to put pepper seedlings in a cold frame or a greenhouse to wait out the colder days and nights.
Just remember to close the greenhouse door before a cold night (and open the door before a hot sunny day.) Otherwise, you might damage or lose your plants.
For more information, check out my article on how to protect plants from cold and frost.
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How To Make Pepper Seeds Germinate Faster
There are several steps you can take to help your pepper plants to germinate faster, including:
- Soak the pepper seeds
- Use new pepper seeds
- Plant pepper seeds at the right time
- Use proper spacing and depth for pepper seeds
- Water pepper seeds properly
By giving them the ideal conditions for growth, you will get a higher germination rate and faster germination.
Let’s review some of the ways to speed up pepper seed germination.
Soak The Pepper Seeds
Pepper seeds need to absorb water before they can begin to germinate. If the air in your house is dry, you will need to water more often.
If you soak pepper seeds before planting them, you can speed up germination. When pepper seeds are soaked before planting, they get a chance to absorb the water they need to germinate, thus giving them a head start.
One option is to soak the seeds in water for a day and then pour the water and seeds through a strainer. If you leave them in water much longer than this, you run the risk of getting rotten seeds.
Another option is to wet a paper towel until it is damp, and then wrap the pepper seeds in the paper towel. Then, put the whole thing in a plastic bag and seal it.
If you need to keep the seeds warmer, leave the bag on your counter in the sun or on a seedling heat mat.
This second method will give the seeds moisture and heat, both of which are necessary for faster germination. Make sure not to let the paper towel dry out, or you will lose the seeds!
If necessary, spray some extra water into the bag to keep the paper towel moist.
If you see your seeds starting to sprout a bit, you will know that they are ready to plant (you don’t need to wait that long, though). At that point, you can either plant the seeds in the garden, or in a tray indoors to wait out the last frosts of the season.
Use Newer, Younger Pepper Seeds
We already talked about how the variety of pepper plant can affect time to germination (for example, hotter peppers generally take longer to germinate.)
The age of seeds can also affect germination rate and time to germination.
Seeds that are more than 1 to 2 years old will have a lower germination rate (a lower percentage of seeds planted will sprout and grow into peppers). If the seeds are old enough, you may not get any seeds to sprout.
It is probably fine to use leftover pepper seeds from last season. However, using seeds that are more than 1 or 2 years old will lower your germination rate.
Choose The Right Time To Plant Pepper Seeds
Soil temperature has a huge impact on seed germination rate and time to germination.
Planting too early can leave pepper seeds or seedlings susceptible to a hard frost. Planting too late can subject them to an early fall frost.
As mentioned above, checking the last frost dates and working backwards will help you to determine when to start seeds indoors and when to transplant outdoors.
Before transplanting peppers, the snow should be gone from the ground and the soil should be completely thawed.
Before you transplant peppers outdoors, check the weather forecast. If you see an unseasonably cold stretch of weather, hold off on planting and keep your seedlings indoors a little longer.
Use Proper Pepper Seed Spacing & Depth
If your pepper seeds are planted too shallow or too deep, they may germinate slowly, or not at all. The ideal depth is ¼ to ½ inch for pepper seeds.
You can learn more about seed planting depth in my article here.
When planting pepper seeds, it is best to plant each seed in its own individual cell in a seed tray.
If the seedlings get too big for their cells, you can transplant each one into a small pot where they can grow until it is warm enough to go outside.
The University of Minnesota Extension suggests that seedlings should be spaced 18 to 24 inches (1.5 to 2 feet) apart. This spacing will give the pepper plants enough room to avoid competing with one another as they grow.
Finally, plant peppers with the rows spaced 24 to 36 inches (2 to 3 feet) apart. This will give you enough room for working the soil, watering and fertilizing your plants, weeding, and harvesting.
Water Your Pepper Seeds Properly
Pepper seed will only germinate and grow properly if the soil has enough moisture. After planting your pepper seeds, keep the soil moist, but not waterlogged.
A spray bottle will help with more precise watering and will prevent over watering. A humidity dome is also helpful for maintaining air and soil moisture.
After pepper plants are established, it is best to water in the morning, when temperatures are cooler and the sun is not at its brightest. This will allow the water to soak into the soil before it can evaporate.
If you think you have a problem with dry soil, check out my article on how to treat dry soil.
How To Help Your Pepper Plants To Grow Better After Germination
Even if your pepper seeds germinate, you still need to take care of them properly to get a bountiful harvest of peppers. Here are some ways to do this.
Enrich Your Garden Soil
This is something to do before the growing season starts. Adding compost or manure to your garden soil has two benefits:
- First, it replaces nutrients that your plants used for last year’s growth.
- Second, it replaces organic material, which allows the soil to stay moist in dry weather while also draining well in wet weather.
You can also add fertilizer or other additives (such as lime or Epsom salt) to your garden to supplement nutrients that your plants need to grow.
However, make sure to get a soil test before you add anything to your garden. You don’t want to end up with an excessive amount of any nutrients.
For example, too much nitrogen can prevent flowering. Too much magnesium can prevent plants from absorbing calcium.
For more information, check out my article on over fertilizing your plants and my article on low-nitrogen fertilizers.
Adjust Soil pH
Pepper plants (and all other plants) will grow best when the soil pH is within an ideal range. The ideal pH range varies by plant, but most will do well between 6.0 and 6.8 (slightly acidic).
Peppers are no exception to this rule. According to the Penn State University Extension, pepper plants grow best with a soil pH of 6.0 to 6.8.
A soil test (mentioned earlier) can help you to determine your soil pH. If it is outside of the ideal range:
- If your soil pH is too low (acidic), you can add lime (calcium carbonate) to raise it.
- If your soil pH is too high (basic or alkaline), you can add sulfur to lower it.
For more information, check out this article from Research Gate on how soil pH can affect nutrient availability for plants.
Conclusion
Now you have a good idea of why your pepper seeds are not germinating. You also have some ideas about how to solve the problem.
You can learn about proper depth and spacing when planting peppers here.
You can learn more about what seeds need to germinate in my article here.
You can learn more about the tomato tree (a relative of the pepper) here.
I hope you found this article helpful – if so, please share it with someone who can use the information.
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~Jonathon