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When to Plant Thai Basil in Divide County, ND

Divide County, North Dakota Zone 4a August

August in Divide County, North Dakota — your action list

August rewards gardeners who work with the weather, not against it. Here's how to stay in step this month in Divide County, North Dakota.

Avg. last frost May 15
Avg. first frost September 20
Soil temp (4") 68°F
Watering High
Pest pressure Moderate
Daylight 14.2 hrs

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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.

Divide County, North Dakota is in USDA Zone 4a. The average last spring frost is May 15 and the first fall frost is September 20, giving you a growing season of approximately 128 days.

At an elevation of 994 feet, Divide County receives approximately 20.5 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Thai Basil to ensure they mature before fall.

Divide County, ND (Zone 4a) Short season
128 days
Last Spring Frost May 15
128 growing days
First Fall Frost September 20

Divide County Soil Profile

Soil Type

Loam

Soil pH

6.2-7.6

Drainage

Well Drained

Thai Basil Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 17 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 29
Recommended (50%) ✗ May not fit
Start indoors: Mar 20 Transplant: Jun 5 🍅 Harvest: Jul 31 – Oct 2
Safe Start (90%) ✗ May not fit
Start indoors: Apr 1 Transplant: Jun 17 🍅 Harvest: Aug 12 – Oct 14

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 Divide County

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

Soil pH

Your soil pH (6.2–7.6) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.9%). 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

2
successive plantings in your 128-day season

Sow every 5.7 weeks. Last sowing by Jul 07 to harvest before frost.

Thai Basil Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.4″/week
Watering frequency 1-2 times/week
Season total 447 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 1.3" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.3" 3" 🚿 Regular watering
Jul 4.3" 1.7" 2.6" 🚿 Regular watering
Aug 4.3" 2.1" 2.2" 🚿 Regular watering
Sep 4.3" 1.8" 2.5" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.4" 0" ❄️ Dormant
Dec 1.1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Divide 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 ~578 GDD — county provides 1,184 GDD Excellent fit

Thai Basil Planting Timeline — Divide County, ND

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 20 Mar 20 – Apr 3
Transplant Outdoors June 5 Jun 5 – Jun 19
Direct Sow May 22 May 22 – Jun 12
Harvest July 31 Jul 31 – Oct 2

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 Harvest
August Harvest
September Harvest
October Harvest
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

128 days in Divide County

Growing Tips for Thai Basil in Divide County

Direct sow Thai Basil outdoors after May 15 in Divide County when soil has warmed and frost danger has passed.

Divide County receives only 20" of rain annually. Thai Basil needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Divide County, ND?

Divide County is in Zone 4a with an average last frost of May 15. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Divide County, ND?

Divide County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 15 and first fall frost is September 20.

🌱

Your Divide County Garden Planner — Free

A 22-page printable planner built for Divide County (Zone 4a). 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 Divide County, ND. Local conditions may vary. Last updated: August 2026.

Sources & credits

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