Blog

When to Plant Hubbard Squash in Vilas County, WI

Vilas County, Wisconsin Zone 4a May

Your May planting checklist for Vilas County, Wisconsin

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

Avg. last frost May 21
Avg. first frost September 29
Soil temp (4") 54°F
Watering Low
Pest pressure Low
Daylight 14.8 hrs
A few tasks this May that'll pay off in June
  • Transplants going out: hubbard squash
  • Direct-sowing: hubbard squash

Instant PDF download. No spam, unsubscribe any time.

Hubbard squash is a large, bumpy-skinned winter squash with dense, sweet, dry flesh ideal for baking and pies. The hard shell allows storage for 6 months or more.

Vilas County, Wisconsin is in USDA Zone 4a. The average last spring frost is May 21 and the first fall frost is September 29, giving you a growing season of approximately 131 days.

At an elevation of 543 feet, Vilas County receives approximately 36.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Hubbard Squash to ensure they mature before fall.

Vilas County, WI (Zone 4a) Short season
131 days
Last Spring Frost May 21
131 growing days
First Fall Frost September 29
Share this guide:

Vilas County Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-7.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Apr 5 Transplant: Jun 7 🍅 Harvest: Sep 20 – Oct 25
Recommended (50%) ✗ May not fit
Start indoors: Apr 9 Transplant: Jun 11 🍅 Harvest: Sep 24 – Oct 29
Safe Start (90%) ✗ May not fit
Start indoors: Apr 21 Transplant: Jun 23 🍅 Harvest: Oct 6 – Nov 10

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 Vilas County

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

Soil pH

Your soil pH (5.8–7.3) overlaps with Hubbard Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

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

How to Plant Hubbard Squash

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

Plant Water Budget

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

Monthly Watering Guide for Hubbard Squash

Hubbard Squash needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Hubbard Squash Needs Rainfall You Supplement Action
Jan 1.3" 0" ❄️ Dormant
Feb 1.7" 0" ❄️ Dormant
Mar 2.6" 0" ❄️ Dormant
Apr 3.6" 0" ❄️ Dormant
May 4.3" 4.3" 0" ✅ Rainfall sufficient
Jun 4.3" 4.3" 0" ✅ Rainfall sufficient
Jul 4.3" 4.2" 0.1" 💧 Light watering
Aug 4.3" 4.4" 0" ✅ Rainfall sufficient
Sep 4.3" 2.9" 1.4" 💧 Light watering
Oct 2.9" 0" ❄️ Dormant
Nov 2.2" 0" ❄️ Dormant
Dec 2.1" 0" ❄️ Dormant

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

Hubbard 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.

Hubbard Squash needs ~1,430 GDD — county provides 1,703 GDD Good fit

Hubbard Squash Planting Timeline — Vilas County, WI

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors April 9 Apr 9 – Apr 23
Transplant Outdoors June 11 Jun 11 – Jun 25
Direct Sow June 4 Jun 4 – Jun 25
Harvest September 24 Sep 24 – Oct 29

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

Month-by-Month Timeline

MonthActivities
January
February
March
April Start Indoors
May
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"/week · Natural rainfall sufficient

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 4a

📆 Growing Season

131 days in Vilas County

Growing Tips for Hubbard Squash in Vilas County

Direct sow Hubbard Squash outdoors after May 21 in Vilas County when soil has warmed and frost danger has passed.

Your 131.0-day growing season in Vilas County is tight for Hubbard Squash (100.0-120.0 days to maturity). Start indoors and choose early-maturing varieties.

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

General growing tips

Start seeds indoors in short-season areas. Requires ample space and rich soil. Harvest when the skin is very hard and the color is deep. Cure in the sun before storing.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hubbard Squash in Vilas County, WI?

Vilas County is in Zone 4a with an average last frost of May 21. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Vilas County, WI?

Vilas County, Wisconsin is in USDA Hardiness Zone 4a. The average last spring frost is May 21 and first fall frost is September 29.

🌱

Your Vilas County Garden Planner — Free

A 24-page printable planner built for Vilas 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 Vilas County, WI. 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.