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When to Plant Hubbard Squash in Yolo County, CA

Yolo County, California Zone 9b May

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Avg. last frost February 9
Avg. first frost December 3
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
Before June arrives, get these ready
  • First harvests: hubbard squash

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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.

Yolo County, California is in USDA Zone 9b. The average last spring frost is February 9 and the first fall frost is December 3, giving you a growing season of approximately 297 days.

At an elevation of 163 feet, Yolo County receives approximately 27.7 inches of rainfall annually with predominantly loam soil. Summer highs average 95°F, so Hubbard Squash may need afternoon shade and extra watering during peak heat.

Yolo County, CA (Zone 9b) Year-round
297 days
Last Spring Frost February 9
297 growing days
First Fall Frost December 3
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Yolo County Soil Profile

Soil Type

Loam

Soil pH

6.7-7.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (158 days to spare)
Start indoors: Dec 28 Transplant: Feb 1 🍅 Harvest: May 17 – Jun 21
Recommended (50%) ✓ Fits season (150 days to spare)
Start indoors: Jan 12 Transplant: Feb 16 🍅 Harvest: Jun 1 – Jul 6
Safe Start (90%) ✓ Fits season (134 days to spare)
Start indoors: Feb 13 Transplant: Mar 20 🍅 Harvest: Jul 3 – Aug 7

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 Yolo County

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

Soil pH

Your soil pH (6.7–7.8) is more alkaline than Hubbard Squash prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Organic Matter

Organic matter is moderate (2.4%). Annual compost additions will help Hubbard Squash.

How to Plant Hubbard Squash

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.4″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,940 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — 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 6" 0" ❄️ Dormant
Feb 4.3" 5.4" 0" ✅ Rainfall sufficient
Mar 4.3" 4" 0.3" 💧 Light watering
Apr 4.3" 2.3" 2" 💧 Light watering
May 4.3" 0.8" 3.5" 🚿 Regular watering
Jun 4.3" 0.1" 4.2" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.3" 4" 🚿 Regular watering
Oct 4.3" 1.1" 3.2" 🚿 Regular watering
Nov 4.3" 2.6" 1.7" 💧 Light watering
Dec 4.3" 5.1" 0" ✅ Rainfall sufficient

Water needs are for active growing months only (Feb–Dec in Yolo 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 ~2,338 GDD — county provides 6,332 GDD Excellent fit

Hubbard Squash Planting Timeline — Yolo County, CA

Hubbard Squash Planting Calendar

Activity When Date Range
Start Indoors January 12 Jan 12 – Jan 26
Transplant Outdoors February 16 Feb 16 – Mar 2
Direct Sow February 9 Feb 9 – Mar 2
Harvest June 1 Jun 1 – Jul 6

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

100–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

297 days in Yolo County

Growing Tips for Hubbard Squash in Yolo County

Direct sow Hubbard Squash outdoors after February 09 in Yolo 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 Yolo County, CA?

Yolo County is in Zone 9b with an average last frost of February 9. Plan your Hubbard Squash planting based on this frost date — see the calendar above for exact timing.

What planting zone is Yolo County, CA?

Yolo County, California is in USDA Hardiness Zone 9b. The average last spring frost is February 9 and first fall frost is December 3.

🌱

Your Yolo County Garden Planner — Free

A 24-page printable planner built for Yolo County (Zone 9b). 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 Yolo County, CA. 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.