When to Plant Peppers in Colorado (2026 Guide)

Peppers are a favorite among gardeners in Colorado due to their rich flavor and wide variety of heat levels, from sweet bell peppers to fiery habaneros. These warm-weather plants require careful timing and specific growing conditions to thrive. Understanding the local frost dates is vital for successful cultivation; for example, in Zone 5b, the median last spring frost date is May 5, indicating when you can safely plant your peppers outdoors.

Starting your peppers indoors can extend your growing season, allowing you to plant earlier and avoid the risk of late spring frost. Depending on where you are in Colorado, you'll want to start your seeds indoors about 8–10 weeks before the last frost date. For those in Colorado Springs, this means starting around mid-February to early March to get a jump on the growing season.

Once the danger of frost has passed, it's time for your transplanted or outdoor-sown peppers to bloom. For gardeners in Aurora and Denver, the growing season can stretch well into October, with the last fall frost typically occurring around October 1. This extensive growing period allows for a bountiful harvest if you plan wisely and care for your plants.

Planting Schedule by USDA Zone in Colorado

Zone	Indoor start	Transplant out	Direct sow	Harvest
Zone 5b	Start seeds indoors February 15 – March 1, ~8–10 weeks before May 5	Transplant outdoors after May 5, when nights are consistently warm	Not recommended, as indoor starting gives better results	Harvest from August 15 to October 1, before the first frost
Zone 5a	Start seeds indoors March 1 – March 15, ~8–10 weeks before May 17	Transplant outdoors after May 17, ensuring warm nights	Direct sowing not recommended — start indoors and transplant	Harvest from August 1 to September 27, before the first fall frost
Zone 6a	Start seeds indoors February 15 – March 1, ~8–10 weeks before April 25	Transplant outdoors after April 25, after the risk of frost has passed	Direct sowing not recommended — start indoors and transplant	Harvest between July 15 and October 16, before the first frost

Peppers Planting Windows in Colorado

Indoor start: Indoors, start seeds between February 15 and March 15, depending on your zone.
Transplant outdoors: In Colorado, transplant outdoors after the last frost, typically between May 5 and May 17.
Harvest: Peppers can typically be harvested from mid-August until late September, depending on your growing zone and frost dates.

Common Mistakes Growing Peppers in Colorado

Many Colorado gardeners underestimate the impact of late spring frosts on peppers, which can set growth back significantly. Always check local forecasts right before planting to ensure you're past the risk of frost.
Ignoring soil temperature is a common mistake. Peppers won't thrive in cold soil, so ensure soil temperatures are at least 65°F before transplanting; this is especially important in high-elevation areas.
Gardeners in Colorado often try to rush into planting without considering their microclimates. Colorful peppers thrive in heat, and colder pockets of 5a might require patience to warm up the soil adequately before planting.
Failure to provide adequate support for pepper plants loaded with fruit leads to broken branches. As peppers develop, consider using stakes or cages to help keep the plants upright during growth.
Many believe all peppers will thrive without spacing. In Colorado's climate, proper spacing is essential to prevent diseases due to humidity and increased moisture, and to allow for adequate airflow.

Frequently Asked Questions

What if I'm in a cold pocket of Colorado?

In colder areas, delay transplanting your peppers until you're certain the frost risk has passed. Consider using row covers to protect young plants and help retain warmth during chilly nights.

Can I still plant peppers in May?

Yes, if you're in a warmer zone, planting in May can be successful. Just ensure that the risk of frost has passed and the soil has warmed sufficiently for healthy growth.

How can I tell if my peppers are ready to harvest?

Peppers are typically ready for harvest when they achieve their full color and firmness. For green peppers, this might be several weeks before they turn red, yellow, or orange, indicating peak sweetness.

Is it necessary to start peppers indoors?

Starting peppers indoors is advisable, especially in Colorado with its variable weather. By beginning early, you can manage the timing better and ensure a longer growing season once transplanting outdoors.

What are the best companion plants for peppers?

Basil is commonly recommended as a companion plant for peppers, along with marigolds for pest control. However, monitor how your plants interact, as individual results may vary depending on local conditions.