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When to Plant Cilantro in Hamilton County, TN

Hamilton County, Tennessee Zone 8a May

Your May game plan for Hamilton County, Tennessee

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost March 28
Avg. first frost November 1
Soil temp (4") 59°F
Watering Low
Pest pressure Moderate
Daylight 13.8 hrs
  1. Begin indoor sowing: cilantro

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

  2. Bring in the cilantro

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

To set up a strong June, finish these tasks
  • First harvests: cilantro

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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.

Hamilton County, Tennessee is in USDA Zone 8a. The average last spring frost is March 28 and the first fall frost is November 1, giving you a growing season of approximately 218 days.

At an elevation of 3,918 feet, Hamilton County receives approximately 51.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 93°F, providing good warmth for Cilantro during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Cilantro root diseases.

Hamilton County, TN (Zone 8a) Long season
218 days
Last Spring Frost March 28
218 growing days
First Fall Frost November 1

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Start indoors: Feb 14 Transplant: Mar 14 🍅 Harvest: Apr 25 – Jun 27
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Feb 21 Transplant: Mar 21 🍅 Harvest: May 2 – Jul 4
Safe Start (90%) ✓ Fits season (120 days to spare)
Start indoors: Mar 13 Transplant: Apr 10 🍅 Harvest: May 22 – Jul 24

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 Hamilton County

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

Soil pH

Your soil pH (5.6–6.9) overlaps with Cilantro's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.9%). Annual compost additions will help Cilantro.

How to Plant Cilantro

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

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

Succession Planting Cilantro

6
successive plantings in your 218-day season

Sow every 4.6 weeks. Last sowing by Sep 02 to harvest before frost.

For a dedicated fall crop, sow by Aug 23.

Plant Water Budget

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

Monthly Watering Guide for Cilantro

Cilantro 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 Cilantro Needs Rainfall You Supplement Action
Jan 4.3" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 2.2" 4.8" 0" ✅ Rainfall sufficient
Apr 2.2" 4" 0" ✅ Rainfall sufficient
May 2.2" 4.3" 0" ✅ Rainfall sufficient
Jun 2.2" 4.6" 0" ✅ Rainfall sufficient
Jul 2.2" 5.4" 0" ✅ Rainfall sufficient
Aug 2.2" 5.2" 0" ✅ Rainfall sufficient
Sep 2.2" 3.8" 0" ✅ Rainfall sufficient
Oct 2.2" 2.7" 0" ✅ Rainfall sufficient
Nov 2.2" 4.2" 0" ✅ Rainfall sufficient
Dec 3.6" 0" ❄️ Dormant

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

Cilantro 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.

Cilantro needs ~988 GDD — county provides 4,305 GDD Excellent fit

Cilantro Planting Timeline — Hamilton County, TN

Cilantro Planting Calendar

Activity When Date Range
Start Indoors February 21 Feb 21 – Mar 7
Transplant Outdoors March 21 Mar 21 – Apr 4
Direct Sow March 14 Mar 14 – Apr 4
Harvest May 2 May 2 – Jul 4
Fall Sowing August 23 Aug 23 – Sep 6

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8a

📆 Growing Season

218 days in Hamilton County

Growing Tips for Cilantro in Hamilton County

Direct sow Cilantro outdoors after March 28 in Hamilton County when soil has warmed and frost danger has passed.

Summer highs in Hamilton County reach 93°F — grow Cilantro as a spring or fall crop. Use shade cloth if planting in summer.

Your generous 218.0-day season in Hamilton County allows multiple plantings of Cilantro. Sow every 20.0 days for continuous harvest.

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

General growing tips

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

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Cilantro in Hamilton County, TN?

Hamilton County is in Zone 8a with an average last frost of March 28. Plan your Cilantro planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, TN?

Hamilton County, Tennessee is in USDA Hardiness Zone 8a. The average last spring frost is March 28 and first fall frost is November 1.

🌱

Your Hamilton County Garden Planner — Free

A 24-page printable planner built for Hamilton County (Zone 8a). 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 Hamilton County, TN. 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.