When to plant Celosia in Denver County, CO
Denver County's short 135-day growing season means one Celosia planting between May 21 and June 11. No fall crop in Zone 6a.
When to Plant Celosia in Denver County, CO
July in Denver County, Colorado — your action list
Your Denver County, Colorado garden is entering a new phase. Here's what's on the schedule for July and why each task matters now.
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Harvest celosia as they ripen
Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.
Coming up in August — start thinking about
- First harvests: celosia
Celosia (Celosia argentea) encompasses the vivid cockscomb (cristata) and feathery plumed (plumosa) types that explode with color in summer heat. Drought-tolerant and disease-resistant, they thrive in the hottest parts of the season and produce long-lasting blooms both in the garden and as cut or dried flowers. A reliable filler in sunny annual beds.
Denver 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 6,818 feet, Denver County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 85°F, providing good warmth for Celosia during the growing season.
Denver County Soil Profile
Soil Type
Loam
Soil pH
6.4-7.8
Drainage
Well Drained
Celosia 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 Denver County
How your county's soil matches Celosia's growing requirements.
Soil pH
Your soil pH (6.4–7.8) is more alkaline than Celosia prefers (6.0–7.0). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Denver County is excellent for Celosia — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (2.2%). Annual compost additions will help Celosia.
How to Plant Celosia
Succession Planting Celosia
Sow every 6.9 weeks. Last sowing by Jun 28 to harvest before frost.
Celosia Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Celosia
Celosia needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.
| Month | Celosia Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.4" | 0" | ❄️ Dormant |
| Feb | — | 1.2" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | — | 2.4" | 0" | ❄️ Dormant |
| May | 2.2" | 2.3" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 1.3" | 0.9" | 💧 Light watering |
| Jul | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Aug | 2.2" | 2.1" | 0.1" | 💧 Light watering |
| Sep | 2.2" | 1.8" | 0.4" | 💧 Light watering |
| Oct | — | 1.8" | 0" | ❄️ Dormant |
| Nov | — | 1.6" | 0" | ❄️ Dormant |
| Dec | — | 1.2" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Denver County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Celosia 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.
Celosia Planting Timeline — Denver County, CO
Celosia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 9 | Apr 9 – Apr 23 |
| Transplant Outdoors | May 21 | May 21 – Jun 4 |
| Direct Sow | May 21 | May 21 – Jun 11 |
| Bloom | July 23 | Jul 23 – Nov 5 |
Plant 0.1" deep · 9" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | Bloom |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.5"/week · Natural rainfall sufficient
📅 Days to Maturity
60–90 days
🧪 Soil pH
Needs 6–7 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 6a
📆 Growing Season
135 days in Denver County
Growing Tips for Celosia in Denver County
Direct sow Celosia outdoors after May 14 in Denver County when soil has warmed and frost danger has passed.
Denver County receives only 20" of rain annually. Celosia needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.
General growing tips
Start seeds indoors 4–6 weeks before last frost, or direct-sow after soil warms above 60°F. Does not transplant well from large pots — sow in small cells or direct-sow. Needs full sun and warm soil; cold stress causes stunting. Pinch first bloom to encourage branching. Water at the base; wet foliage encourages fungal issues. Excellent dried flower — harvest before seeds set for the best color retention.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Celosia in Other Locations
Frequently Asked Questions
When should I plant Celosia in Denver County, CO?
Denver County is in Zone 6a with an average last frost of May 14. Plan your Celosia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Denver County, CO?
Denver County, Colorado is in USDA Hardiness Zone 6a. The average last spring frost is May 14 and first fall frost is September 26.
When should I plant Celosia in Denver County, CO?
In Denver County, CO, plant Celosia after the last frost (around May 14) and before the first frost (around September 26). Best results when soil holds above 50°F.
What growing zone is Denver County, CO for Celosia?
Denver County sits in USDA Zone 6a. Celosia grows reliably in zones 3a through 11b, so it's a good fit here.
Can Celosia grow in Denver County's climate?
Yes — Celosia grows well in Denver County's temperate climate. Denver County averages a 135-day frost-free season, with last frost around May 14 and first frost around September 26.
Your Denver County Garden Planner — Free
A 22-page printable planner built for Denver 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.