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When to Plant Cilantro in Middlesex County, CT

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.

Middlesex County, Connecticut is in USDA Zone 6b. The average last spring frost is April 18 and the first fall frost is October 26, giving you a growing season of approximately 191 days.

At an elevation of 248 feet, Middlesex County receives approximately 40.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90ยฐF, providing good warmth for Cilantro during the growing season.

Middlesex County, CT (Zone 6b) Moderate season
191 days
Last Spring Frost April 18
191 growing days
First Fall Frost October 26

Middlesex County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (92 days to spare)
Start indoors: Mar 7 Transplant: Apr 4 🍅 Harvest: May 16 – Jul 18
Recommended (50%) ✓ Fits season (93 days to spare)
Start indoors: Mar 14 Transplant: Apr 11 🍅 Harvest: May 23 – Jul 25
Safe Start (90%) ✓ Fits season (85 days to spare)
Start indoors: Apr 1 Transplant: Apr 29 🍅 Harvest: Jun 10 – Aug 12

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 190 gal / 100 sq ft
Cilantro needs ~875 GDD — county provides 3,342 GDD Excellent fit

Cilantro Planting Timeline โ€” Middlesex County, CT

Cilantro Planting Calendar

Activity When Date Range
Start Indoors March 14 Mar 14 โ€“ Mar 28
Transplant Outdoors April 11 Apr 11 โ€“ Apr 25
Direct Sow April 4 Apr 4 โ€“ Apr 25
Fall Sowing August 17 Aug 17 โ€“ Aug 31
Harvest May 23 May 23 โ€“ Jul 25

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

Month-by-Month Timeline

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

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

40โ€“60 days

Soil pH

6 โ€“ 7

USDA Zone

Zone 6b

Growing Season

191 days

Growing Tips for Middlesex County

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

Level Up Your Garden

Frequently Asked Questions

When should I plant Cilantro in Middlesex County, CT?

Middlesex County is in Zone 6b with an average last frost of April 18. Plan your Cilantro planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Middlesex County, CT?

Middlesex County, Connecticut is in USDA Hardiness Zone 6b. The average last spring frost is April 18 and first fall frost is October 26.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Middlesex County gardeners in Zone 6b organize planting dates, track what's growing, and never miss a planting window.

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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 Middlesex County, CT. Local conditions may vary. Last updated: April 2026.