When to Plant Microgreens in Aroostook County, ME
Microgreens are young seedlings of vegetables and herbs harvested at the cotyledon or first true leaf stage. They pack concentrated flavors and nutrients in a tiny package.
Aroostook County, Maine is in USDA Zone 3b. 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 Microgreens to ensure they mature before fall.
Aroostook County Soil Profile
Soil Type
Silt Loam
Soil pH
4.9-6.3
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 Aroostook County
How your county's soil matches Microgreens's growing requirements.
Soil pH
Your soil pH (4.9–6.3) is more acidic than Microgreens prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Aroostook County is excellent for Microgreens — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is moderate (3.8%). Annual compost additions will help Microgreens.
How to Plant Microgreens
Fall planting: Sow 12 weeks before your first frost date for a fall harvest.
Succession Planting Microgreens
Sow every 0.7 weeks. Last sowing by Sep 03 to harvest before frost.
For a dedicated fall crop, sow by Jul 02.
Plant Water Budget
Monthly Watering Guide for Microgreens
Microgreens needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.
| Month | Microgreens 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.
Microgreens 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.
Microgreens Planting Timeline — Aroostook County, ME
Microgreens Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 6 | Apr 6 – Apr 20 |
| Transplant Outdoors | May 18 | May 18 – Jun 1 |
| Direct Sow | May 11 | May 11 – Jun 1 |
| Harvest | May 25 | May 25 – Jun 22 |
| Fall Sowing | July 2 | Jul 2 – Jul 16 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow Harvest |
| June | Transplant Outdoors Direct Sow Harvest |
| July | Fall Sowing |
| August | — |
| September | — |
| October | — |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Partial Shade (3-6 hours)
💧 Water
1"/week · Natural rainfall sufficient
📅 Days to Maturity
7–21 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 3b
📆 Growing Season
129 days in Aroostook County
Growing Tips for Microgreens in Aroostook County
Direct sow Microgreens outdoors after May 18 in Aroostook County when soil has warmed and frost danger has passed.
Your generous 129.0-day season in Aroostook County allows multiple plantings of Microgreens. Sow every 3.0 days for continuous harvest.
General growing tips
Sow seeds densely on shallow trays of moist growing medium. Cover until germination, then provide light. Harvest with scissors when 1-3 inches tall. Grow year-round indoors.
Microgreens in Other Locations
Frequently Asked Questions
When should I plant Microgreens in Aroostook County, ME?
Aroostook County is in Zone 3b with an average last frost of May 18. Plan your Microgreens 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 3b. The average last spring frost is May 18 and first fall frost is September 24.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Aroostook County gardeners in Zone 3b organize planting dates, track what's growing, and never miss a planting window.
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