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When to Plant Thai Basil in Hamilton County, NY

Hamilton County, New York Zone 4b May

Your May planting checklist for Hamilton County, New York

We've pulled the most time-sensitive tasks for Hamilton County, New York this May and put them front and centre. Tackle them in order.

Avg. last frost May 20
Avg. first frost September 28
Soil temp (4") 50°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Scatter thai basil into prepared beds

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

A few tasks this May that'll pay off in June
  • Transplants going out: thai basil

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Thai basil has a distinctive anise-licorice flavor with sturdy purple stems and small leaves. It is essential in Thai, Vietnamese, and other Southeast Asian cuisines.

Hamilton County, New York is in USDA Zone 4b. The average last spring frost is May 20 and the first fall frost is September 28, giving you a growing season of approximately 131 days.

At an elevation of 959 feet, Hamilton County receives approximately 49.2 inches of rainfall annually with predominantly silt loam soil. Summer highs average 81°F, so choose short-season varieties of Thai Basil to ensure they mature before fall.

Hamilton County, NY (Zone 4b) Short season
131 days
Last Spring Frost May 20
131 growing days
First Fall Frost September 28

Hamilton County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 18 Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 30
Recommended (50%) ✗ May not fit
Start indoors: Mar 25 Transplant: Jun 10 🍅 Harvest: Aug 5 – Oct 7
Safe Start (90%) ✗ May not fit
Start indoors: Apr 5 Transplant: Jun 21 🍅 Harvest: Aug 16 – Oct 18

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 Thai Basil's growing requirements.

Soil pH

Your soil pH (5.2–6.2) is more acidic than Thai Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

Drainage

Drainage is adequate for Thai Basil.

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Thai Basil.

How to Plant Thai Basil

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

Succession Planting Thai Basil

3
successive plantings in your 131-day season

Sow every 5.7 weeks. Last sowing by Jul 15 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Thai Basil

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

Month Thai Basil Needs Rainfall You Supplement Action
Jan 4" 0" ❄️ Dormant
Feb 2.9" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 4.8" 0" ❄️ Dormant
May 4.3" 4.1" 0.2" 💧 Light watering
Jun 4.3" 5" 0" ✅ Rainfall sufficient
Jul 4.3" 5.1" 0" ✅ Rainfall sufficient
Aug 4.3" 4.3" 0" ✅ Rainfall sufficient
Sep 4.3" 4.6" 0" ✅ Rainfall sufficient
Oct 3.9" 0" ❄️ Dormant
Nov 3.7" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

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

Thai Basil 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.

Thai Basil needs ~672 GDD — county provides 1,408 GDD Excellent fit

Thai Basil Planting Timeline — Hamilton County, NY

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 25 Mar 25 – Apr 8
Transplant Outdoors June 10 Jun 10 – Jun 24
Direct Sow May 27 May 27 – Jun 17
Harvest August 5 Aug 5 – Oct 7

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 4b

📆 Growing Season

131 days in Hamilton County

Growing Tips for Thai Basil in Hamilton County

Direct sow Thai Basil outdoors after May 20 in Hamilton County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Thai basil holds up better to heat in cooking than sweet basil. Pinch flowers to prolong leaf production.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Thai Basil in Hamilton County, NY?

Hamilton County is in Zone 4b with an average last frost of May 20. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Hamilton County, NY?

Hamilton County, New York is in USDA Hardiness Zone 4b. The average last spring frost is May 20 and first fall frost is September 28.

🌱

Your Hamilton County Garden Planner — Free

A 24-page printable planner built for Hamilton County (Zone 4b). 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, NY. 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.