When to Plant Celosia in Trois-Rivieres, QC
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.
Trois-Rivieres, Quebec is in USDA Zone 5b. The average last spring frost is April 24 and the first fall frost is October 8, giving you a growing season of approximately 167 days.
At an elevation of 49 feet, Trois-Rivieres receives approximately 23.5 inches of rainfall annually with predominantly gray-brown podzol soil. Summer highs average 75°F, so choose short-season varieties of Celosia to ensure they mature before fall.
Trois-Rivieres Soil Profile
Soil Type
Gray-Brown Podzol
Soil pH
6.0-7.0
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.
How to Plant Celosia
Celosia Water Budget
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 | — | 0.8" | 0" | ❄️ Dormant |
| Feb | — | 0.9" | 0" | ❄️ Dormant |
| Mar | — | 1.5" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| May | 2.2" | 2.9" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 2.8" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 2.5" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 2.6" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 2.2" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 1.9" | 0.3" | 💧 Light watering |
| Nov | — | 1.7" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Trois-Rivieres). 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 — Trois-Rivieres, QC
Celosia Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 20 | Mar 20 – Apr 3 |
| Transplant Outdoors | May 1 | May 1 – May 15 |
| Direct Sow | May 1 | May 1 – May 22 |
| Bloom | July 3 | Jul 3 – Oct 9 |
Plant 0.1" deep · 9" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| 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: N/A
🗺️ USDA Zone
Zone 5b
📆 Growing Season
167 days in Trois-Rivieres
Growing Tips for Celosia in Trois-Rivieres
Trois-Rivieres receives only 24" 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 Trois-Rivieres, QC?
Trois-Rivieres is in Zone 5b with an average last frost of April 24. Plan your Celosia planting based on this frost date — see the calendar above for exact timing.
What planting zone is Trois-Rivieres, QC?
Trois-Rivieres, Quebec is in USDA Hardiness Zone 5b. The average last spring frost is April 24 and first fall frost is October 8.
Your Trois-Rivieres Garden Planner — Free
A 22-page printable planner built for Trois-Rivieres (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.