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When to Plant Cilantro in Aroostook County, ME

Aroostook County, Maine Zone 4a May

Your May gardening checklist

May is a pivotal month for Aroostook County, Maine gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 18
Avg. first frost September 24
Soil temp (4") 49°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
  1. Get cilantro in the ground

    Your last frost (May 18) has passed. These warm-season crops can handle outdoor soil now.

  2. Direct-sow cilantro

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

To set up a strong June, finish these tasks
  • Starting indoors: cilantro
  • First harvests: cilantro

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Cilantro is a dual-purpose herb providing fresh leaves (cilantro) and dried seeds (coriander). It bolts quickly in heat, producing flowers beloved by beneficial insects.

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 Cilantro to ensure they mature before fall.

Aroostook County, ME (Zone 4a) Short season
129 days
Last Spring Frost May 18
129 growing days
First Fall Frost September 24
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Aroostook County Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (31 days to spare)
Start indoors: Mar 31 Transplant: May 5 🍅 Harvest: Jun 16 – Aug 18
Recommended (50%) ✓ Fits season (31 days to spare)
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Jun 22 – Aug 24
Safe Start (90%) ✓ Fits season (28 days to spare)
Start indoors: Apr 20 Transplant: May 25 🍅 Harvest: Jul 6 – Sep 7

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 Cilantro's growing requirements.

Soil pH

Your soil pH (4.9–6.3) is more acidic than Cilantro prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Aroostook County is excellent for Cilantro — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.8%). Annual compost additions will help Cilantro.

How to Plant Cilantro

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Succession Planting Cilantro

3
successive plantings in your 129-day season

Sow every 4.6 weeks. Last sowing by Jul 26 to harvest before frost.

For a dedicated fall crop, sow by Jul 02.

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
1.3″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Cilantro

Cilantro 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 Cilantro 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 2.2" 3.3" 0" ✅ Rainfall sufficient
Jun 2.2" 3.7" 0" ✅ Rainfall sufficient
Jul 2.2" 3.6" 0" ✅ Rainfall sufficient
Aug 2.2" 3.6" 0" ✅ Rainfall sufficient
Sep 2.2" 3.9" 0" ✅ Rainfall sufficient
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.

Cilantro 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.

Cilantro needs ~425 GDD — county provides 1,096 GDD Excellent fit

Cilantro Planting Timeline — Aroostook County, ME

Cilantro Planting Calendar

Activity When Date Range
Start Indoors April 6 Apr 6 – Apr 20
Transplant Outdoors May 11 May 11 – May 25
Direct Sow May 11 May 11 – Jun 1
Harvest June 22 Jun 22 – Aug 24
Fall Sowing July 2 Jul 2 – Jul 16

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Transplant Outdoors Direct Sow
June Direct Sow Harvest
July Fall Sowing Harvest
August Harvest
September
October
November
December
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Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4a

📆 Growing Season

129 days in Aroostook County

Growing Tips for Cilantro in Aroostook County

Direct sow Cilantro outdoors after May 18 in Aroostook County when soil has warmed and frost danger has passed.

Common pests for Cilantro in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

General growing tips

Succession sow every 2-3 weeks. Provide afternoon shade in warm weather. Harvest leaves before flowering or allow some plants to go to seed for coriander and self-sowing.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Aroostook County, ME?

Aroostook County is in Zone 4a with an average last frost of May 18. Plan your Cilantro 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.

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Your Aroostook County Garden Planner — Free

A 24-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.

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Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Aroostook County, ME. Local conditions may vary. Last updated: May 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.