When to Plant Peppers in Jefferson County, CO
Your May game plan for Jefferson County, Colorado
May is a pivotal month for Jefferson County, Colorado gardens. Focus on these tasks first and you'll set up the rest of the season for success.
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Move peppers from tray to bed
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Direct-sow peppers
Mark the row. Birds and stray feet both have opinions about unmarked beds.
Sweet peppers are warm-season crops producing fruits in a rainbow of colors. They turn from green to red, yellow, or orange as they ripen, increasing in sweetness.
Jefferson County, Colorado is in USDA Zone 6a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.
At an elevation of 5,376 feet, Jefferson County receives approximately 22.7 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Peppers to ensure they mature before fall.
Jefferson County Soil Profile
Soil Type
Loam
Soil pH
6.8-7.7
Drainage
Well Drained
Plant Planting Risk Windows
Percentages indicate frost risk at transplant. The 70% safe window means there is a 30% chance of frost after transplant — suitable for cold-hardy crops or gardeners with frost protection. The 90% safe window is best for tender plants.
Soil Compatibility in Jefferson County
How your county's soil matches Peppers's growing requirements.
Soil pH
Your soil pH (6.8–7.7) is more alkaline than Peppers prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Jefferson County is excellent for Peppers — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.6%). Annual compost additions will help Peppers.
How to Plant Peppers
Succession Planting Peppers
Sow every 6.9 weeks. Last sowing by Jun 28 to harvest before frost.
Plant Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Peppers
Peppers needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Peppers Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.8" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 1.9" | 0" | ❄️ Dormant |
| Apr | — | 2.7" | 0" | ❄️ Dormant |
| May | 4.8" | 2.6" | 2.2" | 💧 Light watering |
| Jun | 4.8" | 1.8" | 3" | 🚿 Regular watering |
| Jul | 4.8" | 1.9" | 2.9" | 🚿 Regular watering |
| Aug | 4.8" | 2.4" | 2.4" | 🚿 Regular watering |
| Sep | 4.8" | 1.7" | 3.1" | 🚿 Regular watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.4" | 0" | ❄️ Dormant |
| Dec | — | 1.4" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Jefferson County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Peppers Heat Requirements (GDD)
What are Growing Degree Days (GDD)?
Growing Degree Days measure the total warmth your plants receive during the growing season. Think of it as a "heat bank" — every day above 50°F deposits warmth that helps your plants grow.
Each plant needs a certain amount of accumulated heat to mature. If your county provides more GDD than the plant needs, it's a great fit. If it's close, you may want to choose faster-maturing varieties or start seeds indoors to get a head start.
Peppers Planting Timeline — Jefferson County, CO
Peppers Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 5 | Mar 5 – Mar 19 |
| Transplant Outdoors | May 28 | May 28 – Jun 11 |
| Direct Sow | May 21 | May 21 – Jun 11 |
| Harvest | July 30 | Jul 30 – Oct 8 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Harvest |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · 1-2 times/week
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 6a
📆 Growing Season
135 days in Jefferson County
Growing Tips for Peppers in Jefferson County
Direct sow Peppers outdoors after May 14 in Jefferson County when soil has warmed and frost danger has passed.
Common pests for Peppers in this region include tomato hornworm and aphids. Use row covers early in the season and inspect plants weekly.
Jefferson County receives only 23" of rain annually. Peppers needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 8-10 weeks before last frost. Transplant when nighttime temperatures stay above 55F. Avoid high-nitrogen fertilizers which promote leaves over fruit.
Recommended Peppers Varieties for Jefferson County
Fast-maturing pepper varieties for shorter seasons
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Isolate 300 ft for purity. Hot and sweet peppers can cross-pollinate.
Peppers in Other Locations
Frequently Asked Questions
When should I plant Peppers in Jefferson County, CO?
Jefferson County is in Zone 6a with an average last frost of May 14. Plan your Peppers planting based on this frost date — see the calendar above for exact timing.
What planting zone is Jefferson County, CO?
Jefferson County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.
Your Jefferson County Garden Planner — Free
A 24-page printable planner built for Jefferson County (Zone 6a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.