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When to Plant Sweet Potatoes in Fairfield County, CT

Fairfield County, Connecticut Zone 6b May

May in the garden — Fairfield County, Connecticut

Your Fairfield County, Connecticut garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 9
Avg. first frost November 3
Soil temp (4") 66°F
Watering Moderate
Pest pressure Moderate
Daylight 14.3 hrs
June prep starts now
  • Starting indoors: sweet potatoes

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Sweet potatoes are a warm-season root crop that produces nutritious, sweet tubers in orange, white, and purple varieties. They need a long, hot growing season.

Fairfield County, Connecticut is in USDA Zone 6b. The average last spring frost is April 9 and the first fall frost is November 3, giving you a growing season of approximately 208 days.

At an elevation of 617 feet, Fairfield County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 91°F, providing good warmth for Sweet Potatoes during the growing season.

Fairfield County, CT (Zone 6b) Long season
208 days
Last Spring Frost April 9
208 growing days
First Fall Frost November 3

Fairfield County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (54 days to spare)
Start indoors: Feb 3 Transplant: Apr 14 🍅 Harvest: Jul 14 – Sep 1
Recommended (50%) ✓ Fits season (54 days to spare)
Start indoors: Feb 12 Transplant: Apr 23 🍅 Harvest: Jul 23 – Sep 10
Safe Start (90%) ✓ Fits season (60 days to spare)
Start indoors: Mar 4 Transplant: May 13 🍅 Harvest: Aug 12 – Sep 30

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 Fairfield County

How your county's soil matches Sweet Potatoes's growing requirements.

Soil pH

Your soil pH (5.1–6.4) overlaps with Sweet Potatoes's range (5.5–6.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Sweet Potatoes.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Sweet Potatoes.

How to Plant Sweet Potatoes

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

Plant Water Budget

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

Monthly Watering Guide for Sweet Potatoes

Sweet Potatoes needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Sweet Potatoes Needs Rainfall You Supplement Action
Jan 3.1" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 4.3" 3.9" 0.4" 💧 Light watering
May 4.3" 3.2" 1.1" 💧 Light watering
Jun 4.3" 3.3" 1" 💧 Light watering
Jul 4.3" 4.6" 0" ✅ Rainfall sufficient
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.6" 0.7" 💧 Light watering
Oct 4.3" 3.5" 0.8" 💧 Light watering
Nov 4.3" 3.6" 0.7" 💧 Light watering
Dec 2.9" 0" ❄️ Dormant

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

Sweet Potatoes 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.

Sweet Potatoes needs ~1,916 GDD — county provides 3,796 GDD Excellent fit

Sweet Potatoes Planting Timeline — Fairfield County, CT

Sweet Potatoes Planting Calendar

Activity When Date Range
Start Indoors February 12 Feb 12 – Feb 26
Transplant Outdoors April 23 Apr 23 – May 7
Direct Sow April 16 Apr 16 – May 7
Harvest July 23 Jul 23 – Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 6b

📆 Growing Season

208 days in Fairfield County

Growing Tips for Sweet Potatoes in Fairfield County

Direct sow Sweet Potatoes outdoors after April 09 in Fairfield County when soil has warmed and frost danger has passed.

General growing tips

Plant slips (rooted sprouts) after soil is thoroughly warm. Build raised mounds for better root development. Cure harvested roots at 80-85F for 10 days to develop sweetness.

Companion Planting

Good Companions

Avoid Planting Near

  • Squash Summer

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sweet Potatoes in Fairfield County, CT?

Fairfield County is in Zone 6b with an average last frost of April 9. Plan your Sweet Potatoes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fairfield County, CT?

Fairfield County, Connecticut is in USDA Hardiness Zone 6b. The average last spring frost is April 9 and first fall frost is November 3.

🌱

Your Fairfield County Garden Planner — Free

A 24-page printable planner built for Fairfield County (Zone 6b). 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 Fairfield County, CT. 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.