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When to Plant Grapes in Winona County, MN

Winona County, Minnesota Zone 4b May

May to-do list for Winona County, Minnesota

May is a pivotal month for Winona County, Minnesota gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost April 30
Avg. first frost October 7
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.6 hrs
  1. Harden off and plant grapes

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

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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.

Winona County, Minnesota is in USDA Zone 4b. The average last spring frost is April 30 and the first fall frost is October 7, giving you a growing season of approximately 160 days.

At an elevation of 1,396 feet, Winona County receives approximately 37.1 inches of rainfall annually with predominantly silt loam soil. Summer highs average 80°F, so choose short-season varieties of Grapes to ensure they mature before fall.

Winona County, MN (Zone 4b) Moderate season
160 days
Last Spring Frost April 30
160 growing days
First Fall Frost October 7
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Winona County Soil Profile

Soil Type

Silt Loam

Soil pH

6.3-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 23
Recommended (50%) ✓ Fits season
Transplant: May 28
Safe Start (90%) ✓ Fits season
Transplant: Jun 12

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 Winona County

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

Soil pH

Your soil pH (6.3–6.8) is within Grapes's preferred range (5.5–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.2%) — 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

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 1.7" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2.5" 0" ❄️ Dormant
Apr 3" 3.9" 0" ✅ Rainfall sufficient
May 3" 4.5" 0" ✅ Rainfall sufficient
Jun 3" 4.2" 0" ✅ Rainfall sufficient
Jul 3" 4.3" 0" ✅ Rainfall sufficient
Aug 3" 4.1" 0" ✅ Rainfall sufficient
Sep 3" 2.8" 0.2" 💧 Light watering
Oct 3" 3.2" 0" ✅ Rainfall sufficient
Nov 2.6" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Winona 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 1,600 GDD May not mature

Grapes Planting Timeline — Winona County, MN

Grapes Planting Calendar

Activity When Date Range
Transplant Outdoors May 28 May 28 – Jun 11

· 72" apart · Rows 96" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
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: ideal

🗺️ USDA Zone

Zone 4b

📆 Growing Season

160 days in Winona County

Growing Tips for Grapes in Winona County

Direct sow Grapes outdoors after April 30 in Winona County when soil has warmed and frost danger has passed.

Your 160.0-day growing season in Winona 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 Winona County, MN?

Winona County is in Zone 4b with an average last frost of April 30. Plan your Grapes planting based on this frost date — see the calendar above for exact timing.

What planting zone is Winona County, MN?

Winona County, Minnesota is in USDA Hardiness Zone 4b. The average last spring frost is April 30 and first fall frost is October 7.

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Your Winona County Garden Planner — Free

A 24-page printable planner built for Winona 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 Winona County, MN. 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.