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When to Plant Celery in Franklin County, ME

Franklin County, Maine Zone 5a May

Your May game plan for Franklin County, Maine

We've pulled the most time-sensitive tasks for Franklin County, Maine this May and put them front and centre. Tackle them in order.

Avg. last frost May 14
Avg. first frost September 28
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Time to transplant celery

    Frost risk is low now in Franklin County, Maine. If you've been covering beds overnight, you can stop.

Before June arrives, get these ready
  • Starting indoors: celery

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Celery is a marshland plant that requires consistent moisture and cool temperatures to produce crisp, flavorful stalks. It is a rewarding but demanding garden crop.

Franklin County, Maine is in USDA Zone 5a. The average last spring frost is May 14 and the first fall frost is September 28, giving you a growing season of approximately 137 days.

At an elevation of 244 feet, Franklin County receives approximately 40.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Celery to ensure they mature before fall.

Franklin County, ME (Zone 5a) Short season
137 days
Last Spring Frost May 14
137 growing days
First Fall Frost September 28
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Franklin County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 6 Transplant: May 11 🍅 Harvest: Aug 3 – Sep 28
Recommended (50%) ✗ May not fit
Start indoors: Apr 9 Transplant: May 14 🍅 Harvest: Aug 6 – Oct 1
Safe Start (90%) ✗ May not fit
Start indoors: Apr 26 Transplant: May 31 🍅 Harvest: Aug 23 – Oct 18

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 Franklin County

How your county's soil matches Celery's growing requirements.

Soil pH

Your soil pH (5.2–6.6) is more acidic than Celery prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.2%). Annual compost additions will help Celery.

How to Plant Celery

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 10 weeks before your first frost date for a fall harvest.

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
1.3″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 60 gal / 100 sq ft

Monthly Watering Guide for Celery

Celery needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Celery Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.9" 0" ❄️ Dormant
Apr 3.1" 0" ❄️ Dormant
May 5.6" 4.1" 1.5" 💧 Light watering
Jun 5.6" 3.4" 2.2" 💧 Light watering
Jul 5.6" 4.1" 1.5" 💧 Light watering
Aug 5.6" 4.1" 1.5" 💧 Light watering
Sep 5.6" 3" 2.6" 💧 Light watering
Oct 3.4" 0" ❄️ Dormant
Nov 2.7" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Franklin County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Celery 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.

Celery needs ~1,000 GDD — county provides 1,370 GDD Excellent fit

Celery Planting Timeline — Franklin County, ME

Celery Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors May 14 May 14 – May 28
Direct Sow April 30 Apr 30 – May 21
Harvest August 6 Aug 6 – Oct 1
Fall Sowing July 20 Jul 20 – Aug 3

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · Only during dry spells

📅 Days to Maturity

80–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5a

📆 Growing Season

137 days in Franklin County

Growing Tips for Celery in Franklin County

Direct sow Celery outdoors after May 14 in Franklin County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 10-12 weeks before last frost. Keep soil consistently moist and never let it dry out. Blanch stalks by mounding soil or using collars for milder flavor.

Companion Planting

Good Companions

Avoid Planting Near

  • Carrots
  • Parsnip

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Celery in Franklin County, ME?

Franklin County is in Zone 5a with an average last frost of May 14. Plan your Celery planting based on this frost date — see the calendar above for exact timing.

What planting zone is Franklin County, ME?

Franklin County, Maine is in USDA Hardiness Zone 5a. The average last spring frost is May 14 and first fall frost is September 28.

🌱

Your Franklin County Garden Planner — Free

A 24-page printable planner built for Franklin County (Zone 5a). 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 Franklin 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.