Blog

When to Plant Butternut Squash in Oliver County, ND

Oliver County, North Dakota Zone 4a May

Your May planting checklist for Oliver County, North Dakota

May is a pivotal month for Oliver 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 14
Avg. first frost September 26
Soil temp (4") 54°F
Watering High
Pest pressure Low
Daylight 14.9 hrs
  1. Plant butternut squash from seed, right in the garden

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

A few tasks this May that'll pay off in June
  • Transplants going out: butternut squash
  • Starting indoors: butternut squash

Instant PDF download. No spam, unsubscribe any time.

Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.

Oliver County, North Dakota is in USDA Zone 4a. The average last spring frost is May 14 and the first fall frost is September 26, giving you a growing season of approximately 135 days.

At an elevation of 721 feet, Oliver County receives approximately 21.1 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Butternut Squash to ensure they mature before fall.

Oliver County, ND (Zone 4a) Short season
135 days
Last Spring Frost May 14
135 growing days
First Fall Frost September 26
Share this guide:

Oliver County Soil Profile

Soil Type

Loam

Soil pH

6.5-7.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Mar 29 Transplant: May 31 🍅 Harvest: Aug 30 – Oct 4
Recommended (50%) ✗ May not fit
Start indoors: Apr 2 Transplant: Jun 4 🍅 Harvest: Sep 3 – Oct 8
Safe Start (90%) ✗ May not fit
Start indoors: Apr 17 Transplant: Jun 19 🍅 Harvest: Sep 18 – Oct 23

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 Oliver County

How your county's soil matches Butternut Squash's growing requirements.

Soil pH

Your soil pH (6.5–7.4) overlaps with Butternut Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

The loam soil in Oliver County is excellent for Butternut Squash — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.0%) — Butternut Squash will thrive.

How to Plant Butternut Squash

1"
Planting Depth
30"
Between Plants
42"
Between Rows

Plant Water Budget

Plant needs
1.1″/week
Rainfall provides
0.7″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 640 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Butternut Squash

Butternut Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.

Month Butternut Squash Needs Rainfall You Supplement Action
Jan 1.5" 0" ❄️ Dormant
Feb 1.1" 0" ❄️ Dormant
Mar 1.7" 0" ❄️ Dormant
Apr 2.3" 0" ❄️ Dormant
May 4.8" 2.4" 2.4" 🚿 Regular watering
Jun 4.8" 1.7" 3.1" 🚿 Regular watering
Jul 4.8" 1.9" 2.9" 🚿 Regular watering
Aug 4.8" 2.5" 2.3" 💧 Light watering
Sep 4.8" 1.7" 3.1" 🚿 Regular watering
Oct 1.7" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1.4" 0" ❄️ Dormant

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

Butternut Squash 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.

Butternut Squash needs ~975 GDD — county provides 1,350 GDD Excellent fit

Butternut Squash Planting Timeline — Oliver County, ND

Butternut Squash Planting Calendar

Activity When Date Range
Start Indoors April 2 Apr 2 – Apr 16
Transplant Outdoors June 4 Jun 4 – Jun 18
Direct Sow May 28 May 28 – Jun 18
Harvest September 3 Sep 3 – Oct 8

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May Direct Sow
June Transplant Outdoors Direct Sow
July
August
September Harvest
October Harvest
November
December
Share this guide:

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.1"/week · 1-2 times/week

📅 Days to Maturity

85–110 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

135 days in Oliver County

Growing Tips for Butternut Squash in Oliver County

Direct sow Butternut Squash outdoors after May 14 in Oliver County when soil has warmed and frost danger has passed.

Common pests for Butternut Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.

Oliver County receives only 21" of rain annually. Butternut Squash needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Butternut Squash in Oliver County, ND?

Oliver County is in Zone 4a with an average last frost of May 14. Plan your Butternut Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Oliver County, ND?

Oliver County, North Dakota is in USDA Hardiness Zone 4a. The average last spring frost is May 14 and first fall frost is September 26.

🌱

Your Oliver County Garden Planner — Free

A 24-page printable planner built for Oliver 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 Oliver 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.