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When to Plant Hubbard Squash in Jones County, IA

Jones County, Iowa Zone 5a May

Top priorities for Jones County, Iowa gardeners in May

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

Avg. last frost April 25
Avg. first frost October 11
Soil temp (4") 57°F
Watering Moderate
Pest pressure Low
Daylight 14.4 hrs
  1. Move hubbard squash into the garden

    Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.

  2. Outdoor sowing time: hubbard squash

    Succession planting is the secret here. Put in a row now, another in 2 weeks, a third in 4.

  3. Indoor seed-starting week for hubbard squash

    Starting these indoors now means sturdy transplants ready the moment your soil warms up.

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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.

Jones County, Iowa is in USDA Zone 5a. The average last spring frost is April 25 and the first fall frost is October 11, giving you a growing season of approximately 169 days.

At an elevation of 837 feet, Jones County receives approximately 31.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Hubbard Squash during the growing season.

Jones County, IA (Zone 5a) Moderate season
169 days
Last Spring Frost April 25
169 growing days
First Fall Frost October 11

Jones County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (15 days to spare)
Start indoors: Mar 17 Transplant: May 5 🍅 Harvest: Aug 18 – Sep 22
Recommended (50%) ✓ Fits season (15 days to spare)
Start indoors: Mar 21 Transplant: May 9 🍅 Harvest: Aug 22 – Sep 26
Safe Start (90%) ✓ Fits season (8 days to spare)
Start indoors: Apr 7 Transplant: May 26 🍅 Harvest: Sep 8 – Oct 13

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 Jones County

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

Soil pH

Your soil pH (5.7–6.8) overlaps with Hubbard Squash's range (6.0–7.0), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Hubbard Squash.

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
0.8″/week
You supply
0.6″/week
Watering frequency 1-2 times/week
Season total 938 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

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 1.2" 0" ❄️ Dormant
Feb 1.5" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 4.3" 2.9" 1.4" 💧 Light watering
May 4.3" 3.4" 0.9" 💧 Light watering
Jun 4.3" 4.5" 0" ✅ Rainfall sufficient
Jul 4.3" 3.7" 0.6" 💧 Light watering
Aug 4.3" 3.2" 1.1" 💧 Light watering
Sep 4.3" 2.6" 1.7" 💧 Light watering
Oct 4.3" 2.3" 2" 💧 Light watering
Nov 2.2" 0" ❄️ Dormant
Dec 1.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Jones 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 ~1,595 GDD — county provides 2,450 GDD Excellent fit

Hubbard Squash Planting Timeline — Jones County, IA

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors March 21 Mar 21 – Apr 4
Transplant Outdoors May 9 May 9 – May 23
Direct Sow May 2 May 2 – May 23
Harvest August 22 Aug 22 – Sep 26

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

Month-by-Month Timeline

MonthActivities
January
February
March Start Indoors
April Start Indoors
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 · 1-2 times/week

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

169 days in Jones County

Growing Tips for Hubbard Squash in Jones County

Direct sow Hubbard Squash outdoors after April 25 in Jones 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 Jones County, IA?

Jones County is in Zone 5a with an average last frost of April 25. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Jones County, IA?

Jones County, Iowa is in USDA Hardiness Zone 5a. The average last spring frost is April 25 and first fall frost is October 11.

🌱

Your Jones County Garden Planner — Free

A 24-page printable planner built for Jones County (Zone 5a). 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 Jones County, IA. 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.