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When to Plant Thai Basil in Sheridan County, ND

Sheridan County, North Dakota Zone 4a May

What to do in May

May is a pivotal month for Sheridan County, North Dakota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 12
Avg. first frost October 1
Soil temp (4") 49°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Scatter thai basil into prepared beds

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

Looking ahead to 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.

Sheridan County, North Dakota is in USDA Zone 4a. The average last spring frost is May 12 and the first fall frost is October 1, giving you a growing season of approximately 142 days.

At an elevation of 1,070 feet, Sheridan County receives approximately 24.1 inches of rainfall annually with predominantly loam soil. Summer highs average 81°F, so choose short-season varieties of Thai Basil to ensure they mature before fall.

Sheridan County, ND (Zone 4a) Short season
142 days
Last Spring Frost May 12
142 growing days
First Fall Frost October 1

Sheridan County Soil Profile

Soil Type

Loam

Soil pH

6.4-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (1 days to spare)
Start indoors: Mar 9 Transplant: May 25 🍅 Harvest: Jul 20 – Sep 21
Recommended (50%) ✓ Fits season (2 days to spare)
Start indoors: Mar 17 Transplant: Jun 2 🍅 Harvest: Jul 28 – Sep 29
Safe Start (90%) ✓ Fits season (5 days to spare)
Start indoors: Mar 25 Transplant: Jun 10 🍅 Harvest: Aug 5 – Oct 7

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 Sheridan County

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

Soil pH

Your soil pH (6.4–7.5) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.5%). 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 142-day season

Sow every 5.7 weeks. Last sowing by Jul 18 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.7″/week
You supply
0.3″/week
Watering frequency 1-2 times/week
Season total 436 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 1.7" 0" ❄️ Dormant
Feb 1.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2.4" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 1.7" 2.6" 🚿 Regular watering
Jul 4.3" 2.4" 1.9" 💧 Light watering
Aug 4.3" 2.2" 2.1" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 1.9" 0" ❄️ Dormant
Dec 1.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Sheridan 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 1,526 GDD Excellent fit

Thai Basil Planting Timeline — Sheridan County, ND

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 17 Mar 17 – Mar 31
Transplant Outdoors June 2 Jun 2 – Jun 16
Direct Sow May 19 May 19 – Jun 9
Harvest July 28 Jul 28 – Sep 29

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April
May 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 · 1-2 times/week

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

142 days in Sheridan County

Growing Tips for Thai Basil in Sheridan County

Direct sow Thai Basil outdoors after May 12 in Sheridan County when soil has warmed and frost danger has passed.

Sheridan County receives only 24" 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 Sheridan County, ND?

Sheridan County is in Zone 4a with an average last frost of May 12. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sheridan County, ND?

Sheridan County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 12 and first fall frost is October 1.

🌱

Your Sheridan County Garden Planner — Free

A 24-page printable planner built for Sheridan 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 Sheridan County, ND. 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.