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When to Plant Basil in Benson County, ND

Benson County, North Dakota Zone 4a May

This month in Benson County, North Dakota

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 13
Avg. first frost September 27
Soil temp (4") 51°F
Watering Low
Pest pressure Low
Daylight 15 hrs
  1. Scatter basil into prepared beds

    Rake a smooth bed, make a shallow furrow, drop seeds at the spacing on the packet, water gently, walk away.

Coming up in June — start thinking about
  • Transplants going out: basil

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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.

Benson County, North Dakota is in USDA Zone 4a. The average last spring frost is May 13 and the first fall frost is September 27, giving you a growing season of approximately 137 days.

At an elevation of 869 feet, Benson County receives approximately 34 inches of rainfall annually with predominantly loam soil. Summer highs average 79°F, so choose short-season varieties of Basil to ensure they mature before fall.

Benson County, ND (Zone 4a) Short season
137 days
Last Spring Frost May 13
137 growing days
First Fall Frost September 27

Benson County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 12 Transplant: May 28 🍅 Harvest: Jul 23 – Sep 24
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 27 Transplant: Jun 12 🍅 Harvest: Aug 7 – Oct 9

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 Benson County

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

Soil pH

Your soil pH (6.6–7.6) is more alkaline than Basil prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (3.3%). 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 137-day season

Sow every 5.7 weeks. Last sowing by Jul 14 to harvest before frost.

Plant Water Budget

Plant needs
0.6″/week
Rainfall provides
1.0″/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 1.2" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 3.8" 0" ❄️ Dormant
May 2.6" 5.4" 0" ✅ Rainfall sufficient
Jun 2.6" 5.2" 0" ✅ Rainfall sufficient
Jul 2.6" 3.9" 0" ✅ Rainfall sufficient
Aug 2.6" 4.1" 0" ✅ Rainfall sufficient
Sep 2.6" 3.1" 0" ✅ Rainfall sufficient
Oct 2" 0" ❄️ Dormant
Nov 1.2" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Benson 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 ~578 GDD — county provides 1,267 GDD Excellent fit

Basil Planting Timeline — Benson County, ND

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

0.6"/week · Natural rainfall sufficient

📅 Days to Maturity

50–75 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4a

📆 Growing Season

137 days in Benson County

Growing Tips for Basil in Benson County

Direct sow Basil outdoors after May 13 in Benson 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 Benson County, ND?

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

What planting zone is Benson County, ND?

Benson County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 13 and first fall frost is September 27.

🌱

Your Benson County Garden Planner — Free

A 24-page printable planner built for Benson 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.

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 Benson 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.