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When to Plant Thai Basil in Madison County, NY

Madison County, New York Zone 5b May

What to do in May

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

Avg. last frost May 10
Avg. first frost October 12
Soil temp (4") 59°F
Watering Low
Pest pressure Low
Daylight 14.5 hrs
  1. Harden off and plant thai basil

    Plant tomatoes deep — bury the stem up to the first true leaves to grow extra roots. Everything else goes in at the same depth it grew in the tray.

  2. Put thai basil seeds straight in the ground

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

Before June arrives, get these ready
  • Starting indoors: 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.

Madison County, New York is in USDA Zone 5b. The average last spring frost is May 10 and the first fall frost is October 12, giving you a growing season of approximately 155 days.

At an elevation of 420 feet, Madison County receives approximately 48.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Thai Basil during the growing season.

Madison County, NY (Zone 5b) Moderate season
155 days
Last Spring Frost May 10
155 growing days
First Fall Frost October 12
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Madison County Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (24 days to spare)
Start indoors: Mar 13 Transplant: May 15 🍅 Harvest: Jul 10 – Sep 11
Recommended (50%) ✓ Fits season (22 days to spare)
Start indoors: Mar 22 Transplant: May 24 🍅 Harvest: Jul 19 – Sep 20
Safe Start (90%) ✓ Fits season (23 days to spare)
Start indoors: Apr 6 Transplant: Jun 8 🍅 Harvest: Aug 3 – Oct 5

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 Madison County

How your county's soil matches Thai Basil's growing requirements.

Soil pH

Your soil pH (5.1–6.3) is more acidic than Thai Basil prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

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

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 155-day season

Sow every 5.7 weeks. Last sowing by Jul 29 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
1.3″/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 3.6" 0" ❄️ Dormant
Feb 3.4" 0" ❄️ Dormant
Mar 4.4" 0" ❄️ Dormant
Apr 4.3" 0" ❄️ Dormant
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 5" 0" ✅ Rainfall sufficient
Aug 4.3" 3.9" 0.4" 💧 Light watering
Sep 4.3" 3.7" 0.6" 💧 Light watering
Oct 4.3" 4.3" 0" ✅ Rainfall sufficient
Nov 4.2" 0" ❄️ Dormant
Dec 3.5" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Madison 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 ~906 GDD — county provides 2,247 GDD Excellent fit

Thai Basil Planting Timeline — Madison County, NY

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 22 Mar 22 – Apr 5
Transplant Outdoors May 24 May 24 – Jun 7
Direct Sow May 17 May 17 – Jun 7
Harvest July 19 Jul 19 – Sep 20

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
May Transplant Outdoors Direct Sow
June Transplant Outdoors Direct Sow
July Harvest
August Harvest
September Harvest
October
November
December
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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 5b

📆 Growing Season

155 days in Madison County

Growing Tips for Thai Basil in Madison County

Direct sow Thai Basil outdoors after May 10 in Madison 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 Madison County, NY?

Madison County is in Zone 5b with an average last frost of May 10. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Madison County, NY?

Madison County, New York is in USDA Hardiness Zone 5b. The average last spring frost is May 10 and first fall frost is October 12.

🌱

Your Madison County Garden Planner — Free

A 24-page printable planner built for Madison County (Zone 5b). 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 Madison 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.