When to plant Impatiens in Aroostook County, ME
Aroostook County sits in cold Zone 4a. Plant Impatiens June 1–June 15 for the single annual harvest; the September 24 first frost closes the window.
When to Plant Impatiens in Aroostook County, ME
Your July planting checklist for Aroostook County, Maine
We've pulled the most time-sensitive tasks for Aroostook County, Maine this July and put them front and centre. Tackle them in order.
-
Begin indoor sowing: impatiens
Label every cell. You will absolutely forget which is which otherwise.
Get ahead of August
- 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.
Aroostook County, Maine is in USDA Zone 4a. The average last spring frost is May 18 and the first fall frost is September 24, giving you a growing season of approximately 129 days.
At an elevation of 314 feet, Aroostook County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 78°F, so choose short-season varieties of Impatiens to ensure they mature before fall.
Aroostook County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.3
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 Aroostook County
How your county's soil matches Impatiens's growing requirements.
Soil pH
Your soil pH (4.9–6.3) is more acidic than Impatiens prefers (6.0–6.5). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Aroostook County is excellent for Impatiens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Impatiens.
How to Plant Impatiens
Succession Planting Impatiens
Sow every 6.9 weeks. Last sowing by Jul 11 to harvest before frost.
Impatiens Water Budget
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 | — | 2.8" | 0" | ❄️ Dormant |
| Feb | — | 2.7" | 0" | ❄️ Dormant |
| Mar | — | 3.3" | 0" | ❄️ Dormant |
| Apr | — | 3.5" | 0" | ❄️ Dormant |
| May | 4.3" | 3.3" | 1" | 💧 Light watering |
| Jun | 4.3" | 3.7" | 0.6" | 💧 Light watering |
| Jul | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Aug | 4.3" | 3.6" | 0.7" | 💧 Light watering |
| Sep | 4.3" | 3.9" | 0.4" | 💧 Light watering |
| Oct | — | 3.2" | 0" | ❄️ Dormant |
| Nov | — | 2.9" | 0" | ❄️ Dormant |
| Dec | — | 3" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Aroostook 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 — Aroostook County, ME
Impatiens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | March 16 | Mar 16 – Mar 30 |
| Transplant Outdoors | June 1 | Jun 1 – Jun 15 |
| Bloom | August 17 | Aug 17 – Oct 12 |
· 10" apart · Rows 12" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | Start Indoors |
| April | — |
| May | — |
| June | Transplant Outdoors |
| July | — |
| August | Bloom |
| September | Bloom |
| October | Bloom |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
60–75 days
🧪 Soil pH
Needs 6–6.5 · Your soil: too_acidic
🗺️ USDA Zone
Zone 4a
📆 Growing Season
129 days in Aroostook County
Growing Tips for Impatiens in Aroostook County
Direct sow Impatiens outdoors after May 18 in Aroostook County when soil has warmed and frost danger has passed.
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 Aroostook County, ME?
Aroostook County is in Zone 4a with an average last frost of May 18. Plan your Impatiens planting based on this frost date — see the calendar above for exact timing.
What planting zone is Aroostook County, ME?
Aroostook County, Maine is in USDA Hardiness Zone 4a. The average last spring frost is May 18 and first fall frost is September 24.
When should I plant Impatiens in Aroostook County, ME?
In Aroostook County, ME, plant Impatiens after the last frost (around May 18) and before the first frost (around September 24). Best results when soil holds above 50°F.
What growing zone is Aroostook County, ME for Impatiens?
Aroostook County sits in USDA Zone 4a. Impatiens grows reliably in zones 2a through 11b, so it's a good fit here.
Can Impatiens grow in Aroostook County's climate?
Yes — Impatiens grows well in Aroostook County's temperate climate. Aroostook County averages a 129-day frost-free season, with last frost around May 18 and first frost around September 24.
Your Aroostook County Garden Planner — Free
A 22-page printable planner built for Aroostook County (Zone 4a). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.