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When to Plant Basil in Ransom County, ND

Ransom County, North Dakota Zone 4a May

Ransom County, North Dakota gardeners: here's your May plan

If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.

Avg. last frost May 8
Avg. first frost October 3
Soil temp (4") 56°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
  1. Time to transplant basil

    Frost risk is low now in Ransom County, North Dakota. If you've been covering beds overnight, you can stop.

  2. Direct-sow basil

    Keep the top inch of soil moist until germination — a gentle morning watering for 5–7 days does the job.

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Basil is a fragrant warm-season herb essential to Italian and Thai cuisines. It comes in many varieties including sweet, Thai, purple, and lemon types.

Ransom County, North Dakota is in USDA Zone 4a. The average last spring frost is May 8 and the first fall frost is October 3, giving you a growing season of approximately 148 days.

At an elevation of 517 feet, Ransom County receives approximately 32.4 inches of rainfall annually with predominantly loam soil. Summer highs average 83°F, so choose short-season varieties of Basil to ensure they mature before fall.

Ransom County, ND (Zone 4a) Short season
148 days
Last Spring Frost May 8
148 growing days
First Fall Frost October 3

Ransom County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (13 days to spare)
Start indoors: Mar 3 Transplant: May 19 🍅 Harvest: Jul 14 – Sep 15
Recommended (50%) ✓ Fits season (8 days to spare)
Start indoors: Mar 13 Transplant: May 29 🍅 Harvest: Jul 24 – Sep 25
Safe Start (90%) ✓ Fits season (9 days to spare)
Start indoors: Mar 23 Transplant: Jun 8 🍅 Harvest: Aug 3 – Oct 5

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 Ransom County

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

Soil pH

Your soil pH (6.7–7.3) overlaps with Basil's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.4%). Annual compost additions will help Basil.

How to Plant Basil

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

Succession Planting Basil

3
successive plantings in your 148-day season

Sow every 5.7 weeks. Last sowing by Jul 20 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
0.9″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Basil

Basil needs approximately 0.6 inches of water per week (2.6" per month). Here's how your county's rainfall compares month by month.

Month Basil Needs Rainfall You Supplement Action
Jan 0.9" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 3.7" 0" ❄️ Dormant
May 2.6" 5.3" 0" ✅ Rainfall sufficient
Jun 2.6" 4.5" 0" ✅ Rainfall sufficient
Jul 2.6" 4.3" 0" ✅ Rainfall sufficient
Aug 2.6" 4.2" 0" ✅ Rainfall sufficient
Sep 2.6" 2.8" 0" ✅ Rainfall sufficient
Oct 2.6" 1.7" 0.9" 💧 Light watering
Nov 1.1" 0" ❄️ Dormant
Dec 0.7" 0" ❄️ Dormant

Water needs are for active growing months only (May–Oct in Ransom County). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

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.

Basil needs ~766 GDD — county provides 1,813 GDD Excellent fit

Basil Planting Timeline — Ransom County, ND

Basil Planting Calendar

Activity When Date Range
Start Indoors March 13 Mar 13 – Mar 27
Transplant Outdoors May 29 May 29 – Jun 12
Direct Sow May 15 May 15 – Jun 5
Harvest July 24 Jul 24 – Sep 25

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

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

148 days in Ransom County

Growing Tips for Basil in Ransom County

Direct sow Basil outdoors after May 08 in Ransom County when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow after last frost. Pinch flower buds to extend leaf production. Harvest leaves from the top down, cutting just above a leaf pair.

Companion Planting

Good Companions

Avoid Planting Near

  • Rue
  • Sage

Check more plant combinations with our Companion Planting Checker →

🌾 Save Your Own Basil Seeds
Life Cycle Annual
Pollination Self-Pollinating
How to Collect Let flower spikes dry brown on the plant.
Storage Store airtight; viable 5 years at 35°F, under 45% humidity.

Isolate 150 ft between varieties. Different basil species can cross.

Frequently Asked Questions

When should I plant Basil in Ransom County, ND?

Ransom County is in Zone 4a with an average last frost of May 8. Plan your Basil planting based on this frost date — see the calendar above for exact timing.

What planting zone is Ransom County, ND?

Ransom County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 8 and first fall frost is October 3.

🌱

Your Ransom County Garden Planner — Free

A 24-page printable planner built for Ransom 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 Ransom 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.