When to plant Impatiens in Larimer County County,
Larimer County County sits in cold Zone 5b. Plant Impatiens May 9–May 23 for the single annual harvest; the October 6 first frost closes the window.
When to Plant Impatiens in Larimer County, CO
Larimer County, Colorado gardeners: here's your June plan
Here's what deserves your attention in Larimer County, Colorado this month. Everything below is tailored to Zone 5b and timed around your local frost dates.
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Time to start impatiens inside
These need a head start before your last frost (May 2). Sow into cells now so you're ready to transplant in a few weeks.
Get ahead of July
- First harvests: impatiens
Impatiens (Impatiens walleriana) are the go-to annual for shaded beds and containers. They produce a continuous carpet of flat-faced blooms from transplant until frost, needing little deadheading. Their preference for consistent moisture and part-shade makes them ideal under trees and along north-facing borders.
Larimer County, Colorado is in USDA Zone 5b. The average last spring frost is May 2 and the first fall frost is October 6, giving you a growing season of approximately 157 days.
At an elevation of 7,108 feet, Larimer County receives approximately 23.4 inches of rainfall annually with predominantly loam soil. Summer highs average 84°F, so choose short-season varieties of Impatiens to ensure they mature before fall.
Larimer County Soil Profile
Soil Type
Loam
Soil pH
6.4-8.2
Drainage
Well Drained
Impatiens 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 Larimer County
How your county's soil matches Impatiens's growing requirements.
Soil pH
Your soil pH (6.4–8.2) is more alkaline than Impatiens prefers (6.0–6.5). Add sulfur or peat moss to lower pH.
Soil Texture
The loam soil in Larimer County is excellent for Impatiens — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Impatiens.
Organic Matter
Organic matter is moderate (2.3%). Annual compost additions will help Impatiens.
How to Plant Impatiens
Succession Planting Impatiens
Sow every 6.9 weeks. Last sowing by Jul 23 to harvest before frost.
Impatiens Water Budget
Water stress score is 8/10 — consider drought-tolerant varieties and mulching
Monthly Watering Guide for Impatiens
Impatiens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Impatiens Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.7" | 0" | ❄️ Dormant |
| Feb | — | 1.3" | 0" | ❄️ Dormant |
| Mar | — | 2.1" | 0" | ❄️ Dormant |
| Apr | — | 2.2" | 0" | ❄️ Dormant |
| May | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Jun | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Jul | 4.3" | 2.3" | 2" | 💧 Light watering |
| Aug | 4.3" | 2.5" | 1.8" | 💧 Light watering |
| Sep | 4.3" | 2" | 2.3" | 🚿 Regular watering |
| Oct | 4.3" | 1.9" | 2.4" | 🚿 Regular watering |
| Nov | — | 1.7" | 0" | ❄️ Dormant |
| Dec | — | 1.3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Oct in Larimer County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Impatiens 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.
Impatiens Planting Timeline — Larimer County, CO
Impatiens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 7 | Mar 7 – Mar 21 |
| Transplant Outdoors | May 9 | May 9 – May 23 |
| Bloom | July 18 | Jul 18 – Oct 17 |
· 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | Transplant Outdoors |
| June | — |
| July | Bloom |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · 2-3 times/week
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–6.5 · Your soil: too_alkaline
🗺️ USDA Zone
Zone 5b
📆 Growing Season
157 days in Larimer County
Growing Tips for Impatiens in Larimer County
Direct sow Impatiens outdoors after May 02 in Larimer County when soil has warmed and frost danger has passed.
Larimer County receives only 23" of rain annually. Impatiens 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 at 70–75°F; germination requires light — do not cover seeds. Transplant after last frost once nights consistently exceed 50°F. Water regularly — wilting causes bud drop and they rarely fully recover the same flush. Watch for impatiens downy mildew (IDM); consider New Guinea impatiens as a resistant alternative in affected regions. Pinch tips at planting to encourage branching.
Companion Planting
Good Companions
Check more plant combinations with our Companion Planting Checker →
Impatiens in Other Locations
Frequently Asked Questions
When should I plant Impatiens in Larimer County, CO?
Larimer County is in Zone 5b with an average last frost of May 2. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Larimer County, CO?
Larimer County, Colorado is in USDA Hardiness Zone 5b. The average last spring frost is May 2 and first fall frost is October 6.
When should I plant Impatiens in Larimer County County, ?
In Larimer County County, , plant Impatiens after the last frost (around May 2) and before the first frost (around October 6). Best results when soil holds above 50°F.
What growing zone is Larimer County County, for Impatiens?
Larimer County County sits in USDA Zone 5b. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.
Can Impatiens grow in Larimer County County's climate?
Yes — Impatiens grows well in Larimer County County's temperate climate. Larimer County County averages a 157-day frost-free season, with last frost around May 2 and first frost around October 6.
Your Larimer County Garden Planner — Free
A 22-page printable planner built for Larimer County (Zone 5b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.