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When to Plant Hubbard Squash in Johnson County, IN

Johnson County, Indiana Zone 6a May

This month in Johnson County, Indiana

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

Avg. last frost April 12
Avg. first frost October 22
Soil temp (4") 63°F
Watering Low
Pest pressure Low
Daylight 14.2 hrs
  1. Time to start hubbard squash inside

    These need a head start before your last frost (April 12). Sow into cells now so you're ready to transplant in a few weeks.

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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.

Johnson County, Indiana is in USDA Zone 6a. The average last spring frost is April 12 and the first fall frost is October 22, giving you a growing season of approximately 193 days.

At an elevation of 1,324 feet, Johnson County receives approximately 36.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Hubbard Squash during the growing season.

Johnson County, IN (Zone 6a) Moderate season
193 days
Last Spring Frost April 12
193 growing days
First Fall Frost October 22

Johnson County Soil Profile

Soil Type

Silt Loam

Soil pH

6.2-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (39 days to spare)
Start indoors: Mar 3 Transplant: Apr 21 🍅 Harvest: Aug 4 – Sep 8
Recommended (50%) ✓ Fits season (39 days to spare)
Start indoors: Mar 8 Transplant: Apr 26 🍅 Harvest: Aug 9 – Sep 13
Safe Start (90%) ✓ Fits season (33 days to spare)
Start indoors: Mar 25 Transplant: May 13 🍅 Harvest: Aug 26 – Sep 30

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 Johnson County

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

Soil pH

Your soil pH (6.2–7.0) is within Hubbard Squash's preferred range (6.0–7.0).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.1%) — 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
0.8″/week
You supply
0.2″/week
Watering frequency Only during dry spells
Season total 357 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 1.7" 0" ❄️ Dormant
Feb 1.6" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 4.3" 3.4" 0.9" 💧 Light watering
May 4.3" 4.6" 0" ✅ Rainfall sufficient
Jun 4.3" 4.1" 0.2" 💧 Light watering
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 4" 0.3" 💧 Light watering
Sep 4.3" 3.1" 1.2" 💧 Light watering
Oct 4.3" 2.9" 1.4" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 2.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Johnson 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 ~1,925 GDD — county provides 3,377 GDD Excellent fit

Hubbard Squash Planting Timeline — Johnson County, IN

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors March 8 Mar 8 – Mar 22
Transplant Outdoors April 26 Apr 26 – May 10
Direct Sow April 19 Apr 19 – May 10
Harvest August 9 Aug 9 – Sep 13

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Only during dry spells

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 6a

📆 Growing Season

193 days in Johnson County

Growing Tips for Hubbard Squash in Johnson County

Direct sow Hubbard Squash outdoors after April 12 in Johnson County when soil has warmed and frost danger has passed.

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 Johnson County, IN?

Johnson County is in Zone 6a with an average last frost of April 12. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Johnson County, IN?

Johnson County, Indiana is in USDA Hardiness Zone 6a. The average last spring frost is April 12 and first fall frost is October 22.

🌱

Your Johnson County Garden Planner — Free

A 24-page printable planner built for Johnson County (Zone 6a). 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 Johnson County, IN. 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.