How and When to Start Pepper Seeds Indoors

Although jalapeño and bell pepper plants are usually sold at garden centers in spring, you can save money on your garden and get your hands on less-common pepper varieties, like aji chilis and fiery ghost peppers, if you grow peppers from seed instead. Pepper seeds can be planted outside in warm climates, but gardeners in cool regions need to start pepper seeds indoors to ensure their plants have enough time to mature before autumn.

In this beginner-friendly guide, you’ll discover the perfect time to sow pepper seeds, along with pepper planting and transplanting tips.

When to Plant Pepper Seeds Indoors

Peppers are long-season crops need a few months to mature, but gardeners can extend their growing season by sowing pepper seeds indoors in early spring. Different pepper varieties take longer to grow than others, so it’s a good idea to consult your seed packets for specific planting instructions. Sweet bell peppers take only 60 to 90 days to bear fruit, but some hot chili peppers can take up to 150 days. Most peppers grow well if you start the seeds indoors about eight to ten weeks before your last frost date.  

How to Plant Pepper Seeds Indoors

When you’ve pinpointed the date to start your pepper seeds, here's how to plant them:

1. Fill individual pots or seed-starting trays with a pre-moistened potting mix.
2. Plant two to three pepper seeds per pot or planting cell and cover the seeds with about ¼ inch of soil.
3. Move the growing containers into a warm location that receives between 12 and 15 hours of bright light daily.
4. Water the seeds regularly to keep the soil consistently moist.

Peppers need lots of light to grow, which can be difficult to achieve indoors. Unless you have a bright window, you need a quality grow light to keep your peppers healthy. LED grow lights hung about 2 to 4 inches above the soil will give your peppers the light they need to sprout. Adjust the light upward as the plants grow.

Aside from light, peppers need plenty of moisture and warmth to germinate. Cover the growing containers with humidity domes and place the pepper containers on top of seedling heating mats to keep the soil temperature at around 70°F.

Depending on the variety, pepper seeds take between 1 and 5 weeks to germinate. After the seeds germinate, remove the humidity domes and turn off the heating mats to prevent the pepper seedlings from drying out.

Caring for Pepper Seedlings Indoors

After they sprout, pepper seeds grow quickly as long as they receive adequate light and moisture. Water indoor peppers regularly to keep the soil moist but not soggy. You may also want to install a small fan near the pepper plants to boost airflow and protect the seedlings from damping off.

When the peppers are a few inches tall and have at least two sets of true leaves, remove the weakest seedlings by gently pulling them up by the roots or clipping off the stems with scissors, leaving only the strongest seedling in each container. Thinning seedlings out gives the remaining peppers more room to grow and prevents overcrowding.

Depending on the size of the growing containers, you may not need to repot your peppers while they’re growing indoors. However, if you notice that the plants look overcrowded or their roots are poking through the bottom of the pots, it may be time to move your plants into larger, 4-inch containers. When repotting, handle pepper roots carefully and bury leggy pepper stems up to their lowest leaves.

How to Transplant Peppers

Gardeners are excited to start planting outdoors in spring, but patience is key when it comes to growing peppers. These heat-loving plants don’t handle cold temperatures well and can be damaged or die back when planted outdoors too early. Wait until the nighttime temperature is consistently above 50°F and the seedlings are several inches tall with multiple sets of leaves to transplant them outside.

To transplant peppers:

1. Prepare the planting spot by mixing compost and a bit of slow-release granular fertilizer into the soil.
2. Plant the pepper seedlings so their roots are covered with about 1 inch of soil (peppers with weak or leggy stems can be buried a little deeper).
3. After the peppers are situated, water them deeply and start fertilizing the plants regularly with a monthly dose of organic fertilizer.

Some pepper plants benefit from staking, but this isn’t always necessary. You can also improve fruiting and help peppers grow bushier with a well-timed pruning. Bell peppers will usually be ready to harvest earlier than chilis; however, once your peppers start producing, harvest often to encourage the plants to produce more fruit.