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When to Plant Thai Basil in Ramsey County, ND

Ramsey County, North Dakota Zone 4a May

Top priorities for Ramsey County, North Dakota gardeners in May

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

Avg. last frost May 13
Avg. first frost September 24
Soil temp (4") 49°F
Watering Moderate
Pest pressure Low
Daylight 15 hrs
  1. Seed thai basil outdoors

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

Before June arrives, get these ready
  • 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.

Ramsey County, North Dakota is in USDA Zone 4a. The average last spring frost is May 13 and the first fall frost is September 24, giving you a growing season of approximately 134 days.

At an elevation of 649 feet, Ramsey 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.

Ramsey County, ND (Zone 4a) Short season
134 days
Last Spring Frost May 13
134 growing days
First Fall Frost September 24

Ramsey County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 13 Transplant: May 29 🍅 Harvest: Jul 24 – Sep 25
Recommended (50%) ✗ May not fit
Start indoors: Mar 18 Transplant: Jun 3 🍅 Harvest: Jul 29 – Sep 30
Safe Start (90%) ✗ May not fit
Start indoors: Mar 31 Transplant: Jun 16 🍅 Harvest: Aug 11 – Oct 13

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 Ramsey County

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

Soil pH

Your soil pH (6.5–7.2) overlaps with Thai Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Ramsey 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 134-day season

Sow every 5.7 weeks. Last sowing by Jul 11 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.8″/week
You supply
0.3″/week
Watering frequency Only during dry spells
Season total 350 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 0.6" 0" ❄️ Dormant
Feb 0.7" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.8" 0" ❄️ Dormant
May 4.3" 3.1" 1.2" 💧 Light watering
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 2.8" 1.5" 💧 Light watering
Aug 4.3" 2.9" 1.4" 💧 Light watering
Sep 4.3" 2.2" 2.1" 💧 Light watering
Oct 1.6" 0" ❄️ Dormant
Nov 0.9" 0" ❄️ Dormant
Dec 0.6" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Ramsey 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 1,440 GDD Excellent fit

Thai Basil Planting Timeline — Ramsey County, ND

Thai Basil Planting Calendar

Activity When Date Range
Start Indoors March 18 Mar 18 – Apr 1
Transplant Outdoors June 3 Jun 3 – Jun 17
Direct Sow May 20 May 20 – Jun 10
Harvest July 29 Jul 29 – Sep 30

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
November
December

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: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

134 days in Ramsey County

Growing Tips for Thai Basil in Ramsey County

Direct sow Thai Basil outdoors after May 13 in Ramsey County when soil has warmed and frost danger has passed.

Ramsey 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 Ramsey County, ND?

Ramsey County is in Zone 4a with an average last frost of May 13. Plan your Thai Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ramsey County, ND?

Ramsey County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 13 and first fall frost is September 24.

🌱

Your Ramsey County Garden Planner — Free

A 24-page printable planner built for Ramsey 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 Ramsey 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.