When to Plant Peppers in Colorado
From sweet bells to fiery habaneros, peppers love heat and reward patience with prolific harvests.
The Short Answer
Colorado Frost Dates
Your planting dates depend on which part of Colorado you're in. Here are the frost date ranges by region:
| Region | Zones | Last Frost (Spring) | First Frost (Fall) |
|---|---|---|---|
| Front Range (Denver) | 5a, 5b, 6a | May 1 - May 15 | Sep 25 - Oct 10 |
| Western Slope | 4b, 5a, 5b, 6a | May 10 - Jun 1 | Sep 15 - Oct 5 |
| Mountain Regions | 3a, 3b, 4a, 4b | Jun 1 - Jun 20 | Aug 25 - Sep 15 |
Peppers Planting Schedule for Colorado
Front Range (Denver) (Zones 5a, 5b, 6a)
Average last frost: May 1 - May 15 · Average first frost: Sep 25 - Oct 10
Western Slope (Zones 4b, 5a, 5b, 6a)
Average last frost: May 10 - Jun 1 · Average first frost: Sep 15 - Oct 5
Mountain Regions (Zones 3a, 3b, 4a, 4b)
Average last frost: Jun 1 - Jun 20 · Average first frost: Aug 25 - Sep 15
Growing Peppers in Colorado
Peppers in Colorado's Climate
Peppers need even more heat than tomatoes, making them one of the most challenging warm-season crops in cold climates. Start seeds indoors 8-10 weeks before your last frost and don't transplant until nighttime temperatures are consistently above 60°F. Choose fast-maturing varieties like Early Jalapeño (60 days) and King of the North (68 days). Wall-o-Water season extenders and black plastic mulch are game-changers for cold-climate pepper growers.
Soil Considerations for Colorado
Alkaline clay soils common along Front Range. Rocky, thin soils in mountains. Amend heavily with compost and sulfur to lower pH. Make sure soil has warmed to at least 65°F before planting peppers outside.
Colorado Climate & Growing Season
High altitude means intense sun but cool nights. Low humidity. Hail risk in late spring. Short but intense growing season at elevation. Peppers cannot tolerate any frost, so wait until all frost danger has passed before transplanting outside. Watch local forecasts carefully in spring.
Growing season length varies across Colorado: Front Range (Denver) (5a, 5b, 6a) has a last frost around May 1 - May 15, while Mountain Regions (3a, 3b, 4a, 4b) sees frost end around Jun 1 - Jun 20. This difference matters for peppers — transplant timing shifts by several weeks across the state.
Growing Tips
Start seeds early — peppers are slow to germinate. Wait until nights are consistently above 55°F before transplanting.
Companion Planting
Plant peppers alongside these companions for better growth:
Keep peppers away from:
The Bottom Line
Last reviewed: March 29, 2026