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When to Plant Thai Basil in Portage County, OH

Portage County, Ohio Zone 6a May

This month in Portage County, Ohio

Here's what deserves your attention in Portage County, Ohio this month. Everything below is tailored to Zone 6a and timed around your local frost dates.

Avg. last frost May 4
Avg. first frost October 13
Soil temp (4") 57°F
Watering Low
Pest pressure Low
Daylight 14.3 hrs
  1. Move thai basil into the garden

    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

    Sow every 2 weeks for a continuous harvest. A single big planting means a single big glut.

Get ahead of June
  • 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.

Portage County, Ohio is in USDA Zone 6a. The average last spring frost is May 4 and the first fall frost is October 13, giving you a growing season of approximately 162 days.

At an elevation of 1,164 feet, Portage County receives approximately 41 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Thai Basil during the growing season.

Portage County, OH (Zone 6a) Moderate season
162 days
Last Spring Frost May 4
162 growing days
First Fall Frost October 13

Portage County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (30 days to spare)
Start indoors: Mar 10 Transplant: May 12 🍅 Harvest: Jul 7 – Sep 8
Recommended (50%) ✓ Fits season (29 days to spare)
Start indoors: Mar 16 Transplant: May 18 🍅 Harvest: Jul 13 – Sep 14
Safe Start (90%) ✓ Fits season (24 days to spare)
Start indoors: Apr 3 Transplant: Jun 5 🍅 Harvest: Jul 31 – Oct 2

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 Portage County

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

Soil pH

Your soil pH (6.2–6.8) is within Thai Basil's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (4.2%) — Thai Basil will thrive.

How to Plant Thai Basil

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

Succession Planting Thai Basil

3
successive plantings in your 162-day season

Sow every 5.7 weeks. Last sowing by Jul 30 to harvest before frost.

Plant Water Budget

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

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.9" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.8" 0" ❄️ Dormant
Apr 4.6" 0" ❄️ Dormant
May 4.3" 4.7" 0" ✅ Rainfall sufficient
Jun 4.3" 4.8" 0" ✅ Rainfall sufficient
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4.9" 0" ✅ Rainfall sufficient
Sep 4.3" 3.2" 1.1" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.8" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Portage 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 ~859 GDD — county provides 2,227 GDD Excellent fit

Thai Basil Planting Timeline — Portage County, OH

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 – Mar 30
Transplant Outdoors May 18 May 18 – Jun 1
Direct Sow May 11 May 11 – Jun 1
Harvest July 13 Jul 13 – Sep 14

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

Month-by-Month Timeline

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

🗺️ USDA Zone

Zone 6a

📆 Growing Season

162 days in Portage County

Growing Tips for Thai Basil in Portage County

Direct sow Thai Basil outdoors after May 04 in Portage 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 Portage County, OH?

Portage County is in Zone 6a with an average last frost of May 4. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Portage County, OH?

Portage County, Ohio is in USDA Hardiness Zone 6a. The average last spring frost is May 4 and first fall frost is October 13.

🌱

Your Portage County Garden Planner — Free

A 24-page printable planner built for Portage 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Portage County, OH. 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.