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When to Plant Cranberries in Franklin County, ME

Franklin County, Maine Zone 5a May

What to do in May

A quick May briefing for Franklin County, Maine gardeners — what's urgent, what's next, and what can wait.

Avg. last frost May 14
Avg. first frost September 28
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
Before June arrives, get these ready
  • Transplants going out: cranberries

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Cranberries are low-growing, vine-like shrubs that produce tart red berries in fall. They grow in acidic, boggy conditions and are surprisingly easy to cultivate.

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 Cranberries 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) ✓ Fits season
Transplant: Jun 1
Recommended (50%) ✓ Fits season
Transplant: Jun 4
Safe Start (90%) ✓ Fits season
Transplant: Jun 21

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 Cranberries's growing requirements.

Soil pH

Your soil pH (5.2–6.6) is more alkaline than Cranberries prefers (4.0–5.5). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

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

How to Plant Cranberries

36"
Between Plants
48"
Between Rows

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
1.3″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 304 gal / 100 sq ft

Monthly Watering Guide for Cranberries

Cranberries needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Cranberries 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 6.5" 4.1" 2.4" 💧 Light watering
Jun 6.5" 3.4" 3.1" 💧 Light watering
Jul 6.5" 4.1" 2.4" 💧 Light watering
Aug 6.5" 4.1" 2.4" 💧 Light watering
Sep 6.5" 3" 3.5" 🚿 Regular 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.

Cranberries 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.

Cranberries needs ~9,125 GDD — county provides 1,370 GDD May not mature

Cranberries Planting Timeline — Franklin County, ME

Cranberries Planting Calendar

Activity When Date Range
Transplant Outdoors June 4 Jun 4 – Jun 18

· 36" apart · Rows 48" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.5"/week · Only during dry spells

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 4–5.5 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 5a

📆 Growing Season

137 days in Franklin County

Growing Tips for Cranberries in Franklin County

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

Your 137.0-day growing season in Franklin County is tight for Cranberries (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Create an acidic, consistently moist bed with peat moss. Cranberries do not need to be flooded to grow; flooding is only used for commercial harvesting. Mulch with sand in early spring.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cranberries in Franklin County, ME?

Franklin County is in Zone 5a with an average last frost of May 14. Plan your Cranberries 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.

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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.