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When to plant Thai Basil in Fulton County County,

The best window to plant Thai Basil in Fulton County County, is April 27–May 18, when soil warms to 50°F. Last frost typically hits April 20; first frost October 16.

When to Plant Thai Basil in Fulton County, IL

Fulton County, Illinois Zone 6a June

Fulton County, Illinois gardeners: here's your June plan

Your Fulton County, Illinois garden is entering a new phase. Here's what's on the schedule for June and why each task matters now.

Avg. last frost April 20
Avg. first frost October 16
Soil temp (4") 70°F
Watering Low
Pest pressure High
Daylight 14.9 hrs
  1. Start thai basil under lights

    Give them 6–8 weeks indoors before the last frost and you'll transplant into warm soil with seedlings that are already leaping.

  2. Collect thai basil at their peak

    The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.

July prep starts now
  • First harvests: 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.

Fulton County, Illinois is in USDA Zone 6a. The average last spring frost is April 20 and the first fall frost is October 16, giving you a growing season of approximately 179 days.

At an elevation of 1,162 feet, Fulton County receives approximately 39.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 83°F, so choose short-season varieties of Thai Basil to ensure they mature before fall.

Fulton County, IL (Zone 6a) Moderate season
179 days
Last Spring Frost April 20
179 growing days
First Fall Frost October 16
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Fulton County Soil Profile

Soil Type

Silt Loam

Soil pH

6.1-6.7

Drainage

Well Drained

Thai Basil Planting Risk Windows

Early Start (70% safe) ✓ Fits season (47 days to spare)
Start indoors: Feb 24 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 25
Recommended (50%) ✓ Fits season (46 days to spare)
Start indoors: Mar 2 Transplant: May 4 🍅 Harvest: Jun 29 – Aug 31
Safe Start (90%) ✓ Fits season (47 days to spare)
Start indoors: Mar 14 Transplant: May 16 🍅 Harvest: Jul 11 – Sep 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.

Soil Compatibility in Fulton County

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

Soil pH

Your soil pH (6.1–6.7) is within Thai Basil's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.0%) — Thai Basil will thrive.

How to Plant Thai Basil

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

Succession Planting Thai Basil

4
successive plantings in your 179-day season

Sow every 5.7 weeks. Last sowing by Aug 02 to harvest before frost.

Thai Basil 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 117 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 1.8" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 4.3" 3.7" 0.6" 💧 Light watering
May 4.3" 4.5" 0" ✅ Rainfall sufficient
Jun 4.3" 5.5" 0" ✅ Rainfall sufficient
Jul 4.3" 4.3" 0" ✅ Rainfall sufficient
Aug 4.3" 3.6" 0.7" 💧 Light watering
Sep 4.3" 3.3" 1" 💧 Light watering
Oct 4.3" 3.6" 0.7" 💧 Light watering
Nov 2.5" 0" ❄️ Dormant
Dec 2.3" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Fulton 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 ~766 GDD — county provides 2,192 GDD Excellent fit

Thai Basil Planting Timeline — Fulton County, IL

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 2 Mar 2 – Mar 16
Transplant Outdoors May 4 May 4 – May 18
Direct Sow April 27 Apr 27 – May 18
Harvest June 29 Jun 29 – Aug 31

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

179 days in Fulton County

Growing Tips for Thai Basil in Fulton County

Direct sow Thai Basil outdoors after April 20 in Fulton 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 Fulton County, IL?

Fulton County is in Zone 6a with an average last frost of April 20. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Fulton County, IL?

Fulton County, Illinois is in USDA Hardiness Zone 6a. The average last spring frost is April 20 and first fall frost is October 16.

When should I plant Thai Basil in Fulton County, ?

In Fulton County, , plant Thai Basil after the last frost (around April 20) and before the first frost (around October 16). Best results when soil holds above 50°F.

What growing zone is Fulton County, for Thai Basil?

Fulton County sits in USDA Zone 6a. Thai Basil grows reliably in zones 4a through 11b, so it's a good fit here.

Can Thai Basil grow in Fulton County's climate?

Yes — Thai Basil grows well in Fulton County's temperate climate. Fulton County averages a 179-day frost-free season, with last frost around April 20 and first frost around October 16.

🌱

Your Fulton County Garden Planner — Free

A 22-page printable planner built for Fulton County (Zone 6a). 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 Fulton County, IL. Local conditions may vary. Last updated: June 2026.

Sources & credits

Every number on this page traces back to a primary horticulture or government data source. Click through to verify.