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When to Plant Lemon Thyme in New Haven County, CT

New Haven County, Connecticut Zone 6b May

Your May game plan for New Haven County, Connecticut

Your garden in New Haven County, Connecticut is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost April 23
Avg. first frost October 19
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs

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Lemon thyme is a low-growing perennial herb with tiny, citrus-scented leaves. It combines the savory quality of thyme with a bright lemon flavor, excellent with fish and poultry.

New Haven County, Connecticut is in USDA Zone 6b. The average last spring frost is April 23 and the first fall frost is October 19, giving you a growing season of approximately 179 days.

At an elevation of 509 feet, New Haven County receives approximately 49.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Lemon Thyme during the growing season.

New Haven County, CT (Zone 6b) Moderate season
179 days
Last Spring Frost April 23
179 growing days
First Fall Frost October 19

New Haven County Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (44 days to spare)
Transplant: Apr 21 🍅 Harvest: Jun 30 – Sep 1
Recommended (50%) ✓ Fits season (39 days to spare)
Transplant: Apr 30 🍅 Harvest: Jul 9 – Sep 10
Safe Start (90%) ✓ Fits season (30 days to spare)
Transplant: May 23 🍅 Harvest: Aug 1 – Oct 3

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 New Haven County

How your county's soil matches Lemon Thyme's growing requirements.

Soil pH

Your soil pH (5.0–6.5) is more acidic than Lemon Thyme prefers (6.0–8.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in New Haven County is excellent for Lemon Thyme — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is moderate (3.1%). Annual compost additions will help Lemon Thyme.

How to Plant Lemon Thyme

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

Succession Planting Lemon Thyme

2
successive plantings in your 179-day season

Sow every 8 weeks. Last sowing by Jul 21 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Lemon Thyme

Lemon Thyme 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 Lemon Thyme Needs Rainfall You Supplement Action
Jan 3.5" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 4.1" 0" ❄️ Dormant
Apr 2.2" 4.2" 0" ✅ Rainfall sufficient
May 2.2" 4.5" 0" ✅ Rainfall sufficient
Jun 2.2" 4.1" 0" ✅ Rainfall sufficient
Jul 2.2" 5.2" 0" ✅ Rainfall sufficient
Aug 2.2" 4.4" 0" ✅ Rainfall sufficient
Sep 2.2" 3.6" 0" ✅ Rainfall sufficient
Oct 2.2" 4.2" 0" ✅ Rainfall sufficient
Nov 4.2" 0" ❄️ Dormant
Dec 4" 0" ❄️ Dormant

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

Lemon Thyme 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.

Lemon Thyme needs ~1,340 GDD — county provides 2,998 GDD Excellent fit

Lemon Thyme Planting Timeline — New Haven County, CT

Lemon Thyme Planting Calendar

Activity When Date Range
Transplant Outdoors April 30 Apr 30 – May 14
Harvest July 9 Jul 9 – Sep 10

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–8 · Your soil: too_acidic

🗺️ USDA Zone

Zone 6b

📆 Growing Season

179 days in New Haven County

Growing Tips for Lemon Thyme in New Haven County

Direct sow Lemon Thyme outdoors after April 23 in New Haven County when soil has warmed and frost danger has passed.

General growing tips

Start from cuttings or divisions. Plant in well-drained soil. Trim back after flowering. Use as a fragrant ground cover or edging plant along garden paths.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Lemon Thyme in New Haven County, CT?

New Haven County is in Zone 6b with an average last frost of April 23. Plan your Lemon Thyme planting based on this frost date — see the calendar above for exact timing.

What planting zone is New Haven County, CT?

New Haven County, Connecticut is in USDA Hardiness Zone 6b. The average last spring frost is April 23 and first fall frost is October 19.

🌱

Your New Haven County Garden Planner — Free

A 24-page printable planner built for New Haven 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 New Haven 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.