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When to Plant Grapes in Slope County, ND

Slope County, North Dakota Zone 4b May

Your May planting checklist for Slope County, North Dakota

Your Slope County, North Dakota garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost May 15
Avg. first frost September 24
Soil temp (4") 52°F
Watering Moderate
Pest pressure Low
Daylight 14.8 hrs
To set up a strong June, finish these tasks
  • Transplants going out: grapes

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Grapes are vigorous climbing vines producing clusters of sweet or wine-quality fruits. They require training on a trellis or arbor and annual pruning for best production.

Slope County, North Dakota is in USDA Zone 4b. The average last spring frost is May 15 and the first fall frost is September 24, giving you a growing season of approximately 132 days.

At an elevation of 1,230 feet, Slope County receives approximately 31.4 inches of rainfall annually with predominantly loam soil. Summer highs average 80°F, so choose short-season varieties of Grapes to ensure they mature before fall.

Slope County, ND (Zone 4b) Short season
132 days
Last Spring Frost May 15
132 growing days
First Fall Frost September 24
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Slope County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Jun 9
Recommended (50%) ✓ Fits season
Transplant: Jun 12
Safe Start (90%) ✓ Fits season
Transplant: Jun 29

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 Slope County

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

Soil pH

Your soil pH (6.7–7.6) is more alkaline than Grapes prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Grapes.

Organic Matter

Organic matter is excellent (4.2%) — Grapes will thrive.

How to Plant Grapes

72"
Between Plants
96"
Between Rows

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
1.0″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Grapes

Grapes needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Grapes Needs Rainfall You Supplement Action
Jan 2.4" 0" ❄️ Dormant
Feb 1.9" 0" ❄️ Dormant
Mar 3.1" 0" ❄️ Dormant
Apr 2.9" 0" ❄️ Dormant
May 3" 3.3" 0" ✅ Rainfall sufficient
Jun 3" 2.3" 0.7" 💧 Light watering
Jul 3" 3.1" 0" ✅ Rainfall sufficient
Aug 3" 3" 0" ✅ Rainfall sufficient
Sep 3" 2.3" 0.7" 💧 Light watering
Oct 2.7" 0" ❄️ Dormant
Nov 2.3" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

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

Grapes 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.

Grapes needs ~9,125 GDD — county provides 1,320 GDD May not mature

Grapes Planting Timeline — Slope County, ND

Grapes Planting Calendar

Activity When Date Range
Transplant Outdoors June 12 Jun 12 – Jun 26

· 72" apart · Rows 96" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Natural rainfall sufficient

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 4b

📆 Growing Season

132 days in Slope County

Growing Tips for Grapes in Slope County

Direct sow Grapes outdoors after May 15 in Slope County when soil has warmed and frost danger has passed.

Your 132.0-day growing season in Slope County is tight for Grapes (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Provide a strong trellis system. Prune heavily in late winter while dormant. Thin fruit clusters for larger berries. Good air circulation prevents fungal diseases.

Companion Planting

Good Companions

Avoid Planting Near

  • Cabbage
  • Radish

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Grapes in Slope County, ND?

Slope County is in Zone 4b with an average last frost of May 15. Plan your Grapes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Slope County, ND?

Slope County, North Dakota is in USDA Hardiness Zone 4b. The average last spring frost is May 15 and first fall frost is September 24.

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Your Slope County Garden Planner — Free

A 24-page printable planner built for Slope County (Zone 4b). 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 Slope 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.