When to plant bell peppers in Colorado
Colorado’s average last spring frost is May 5, and the first fall frost typically arrives around October 1 — about 149 frost-free days (USDA zones 3b, 4b, 5a, 5b, 6a, 7a). Bell Pepper needs 60–90 days to mature, which fits comfortably within Colorado's growing season.
Colorado covers a wide range of climates, so your exact frost dates may differ from the state average by two weeks or more. For dates tuned to your town, use the calendar generator.
When to plant bell peppers in Colorado: the short answer
For a spring planting, plant out May 12 – May 29, with seeds started indoors Mar 3 – Mar 17. Wait until the soil is at least 60°F and frost is over.
Windows are ~1–2 week bands around each date. Frost dates are a statewide average from NOAA/NCEI normals; your town may differ by two weeks or more. Calendar year 2026.
How to grow bell peppers in Colorado, step by step
- Start seeds indoors (Mar 3 – Mar 17). Sow seeds ¼ inch deep in seed-starting mix under bright light. They take 7-14 days to sprout, fastest in soil around 82°F. Harden seedlings off for a week before they go outside.
- Prepare the bed. They need at least six to eight hours of direct sun a day and loose soil at least 12 inches deep, with a pH between 5.5 and 7.0. Dig in compost before planting.
- Plant out (May 12 – May 29). Space plants about 18 inches apart in rows 30 inches apart. It is killed by frost, so nothing goes outside until the danger has passed.
- Water and feed. Give it steady, even moisture, about an inch of water a week from rain or the hose.
- Watch for pests and problems. Pests: aphids, flea beetle, pepper maggot, tomato hornworm. Diseases and disorders: bacterial leaf spot, anthracnose, blossom-end rot (calcium disorder), phytophthora blight.
- Harvest (from about Jul 18 – Aug 17). Bell Pepper takes 60-90 days to reach harvest. Needs warm soil; wait until nights stay above 55 F to transplant. Green peppers are just unripe coloured peppers left another 2-3 weeks.
Figures come from our crop data; dates use Colorado’s average frost dates. More in the full bell pepper growing guide.
Bell Pepper planting dates by USDA zone in Colorado
Colorado spans USDA zones 3b, 4b, 5a, 5b, 6a, 7a. Colder zones, usually higher or further inland, have a later last spring frost and an earlier first fall frost than the state average, so the bell pepper dates shift with them.
| Zone | Last frost | First frost | Season | Start indoors | Plant bell pepper |
|---|---|---|---|---|---|
| Zone 3 | May 15 | Sep 15 | 120 days | Mar 13 – Mar 27 | May 22 – Jun 8 |
| Zone 4 | May 10 | Sep 25 | 135 days | Mar 8 – Mar 22 | May 17 – Jun 3 |
| Zone 5 | Apr 30 | Oct 5 | 160 days | Feb 26 – Mar 12 | May 7 – May 24 |
| Zone 6 | Apr 15 | Oct 15 | 185 days | Feb 11 – Feb 25 | Apr 22 – May 9 |
| Zone 7 | Apr 5 | Oct 25 | 200 days | Feb 1 – Feb 15 | Apr 12 – Apr 29 |
When to plant bell peppers in nearby states
Questions gardeners in Colorado ask
When is the best time to plant bell peppers in Colorado?
Plant bell pepper transplants outdoors in Colorado between May 12 and May 29. That timing is set by Colorado's average last spring frost of May 5; Colorado spans several climates, so cooler and higher parts of the state run later.
When should I start bell pepper seeds indoors in Colorado?
Start seeds indoors between March 3 and March 17, about 8 weeks before the last frost, so the seedlings are ready to plant out from May 12.
What is the latest I can plant bell peppers in Colorado?
About August 2. Bell peppers need at least 60 days to mature after transplanting, and frost around October 1 ends the season, so later plantings risk being cut short.
When will bell peppers planted in Colorado be ready to harvest?
Planted on time, bell peppers are usually ready from about July 18 to August 17, 60-90 days after transplanting.
When is the last frost in Colorado?
On average around May 5, with the first fall frost around October 1 - about 149 frost-free days. Your town may differ by two weeks or more.