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When to Plant Pumpkin in Colusa County, CA

Colusa County, California Zone 9b May

What to do in May

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

Avg. last frost March 6
Avg. first frost November 28
Soil temp (4") 74°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
To set up a strong June, finish these tasks
  • First harvests: pumpkin

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Pumpkins are large-fruited squash varieties grown for eating, decoration, and seed production. They require ample space and a long, warm growing season.

Colusa County, California is in USDA Zone 9b. The average last spring frost is March 6 and the first fall frost is November 28, giving you a growing season of approximately 267 days.

At an elevation of 112 feet, Colusa County receives approximately 29.8 inches of rainfall annually with predominantly loam soil. Summer highs average 94°F, providing good warmth for Pumpkin during the growing season.

Colusa County, CA (Zone 9b) Long season
267 days
Last Spring Frost March 6
267 growing days
First Fall Frost November 28

Colusa County Soil Profile

Soil Type

Loam

Soil pH

6.6-7.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (123 days to spare)
Start indoors: Jan 26 Transplant: Mar 2 🍅 Harvest: Jun 1 – Jul 20
Recommended (50%) ✓ Fits season (120 days to spare)
Start indoors: Feb 6 Transplant: Mar 13 🍅 Harvest: Jun 12 – Jul 31
Safe Start (90%) ✓ Fits season (98 days to spare)
Start indoors: Mar 21 Transplant: Apr 25 🍅 Harvest: Jul 25 – Sep 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 Colusa County

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

Soil pH

Your soil pH (6.6–7.5) is within Pumpkin's preferred range (6.0–7.5).

Soil Texture

The loam soil in Colusa County is excellent for Pumpkin — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Pumpkin.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help Pumpkin.

How to Plant Pumpkin

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

Plant Water Budget

Plant needs
1.3″/week
Rainfall provides
0.5″/week
You supply
1.5″/week
Watering frequency 2-3 times/week
Season total 3,482 gal / 100 sq ft
Drought risk

Water stress score is 8/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for Pumpkin

Pumpkin needs approximately 1.3 inches of water per week (5.6" per month). Here's how your county's rainfall compares month by month.

Month Pumpkin Needs Rainfall You Supplement Action
Jan 6.2" 0" ❄️ Dormant
Feb 6.7" 0" ❄️ Dormant
Mar 5.6" 4.7" 0.9" 💧 Light watering
Apr 5.6" 2" 3.6" 🚿 Regular watering
May 5.6" 0.7" 4.9" 🚿 Regular watering
Jun 5.6" 0.1" 5.5" 🚿 Regular watering
Jul 5.6" 0" 5.6" 🚿 Regular watering
Aug 5.6" 0" 5.6" 🚿 Regular watering
Sep 5.6" 0.3" 5.3" 🚿 Regular watering
Oct 5.6" 1.1" 4.5" 🚿 Regular watering
Nov 5.6" 3" 2.6" 💧 Light watering
Dec 4.9" 0" ❄️ Dormant

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

Pumpkin 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.

Pumpkin needs ~2,101 GDD — county provides 5,473 GDD Excellent fit

Pumpkin Planting Timeline — Colusa County, CA

Pumpkin Planting Calendar

Activity When Date Range
Start Indoors February 6 Feb 6 – Feb 20
Transplant Outdoors March 13 Mar 13 – Mar 27
Direct Sow March 6 Mar 6 – Mar 27
Harvest June 12 Jun 12 – Jul 31

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1.3"/week · 2-3 times/week

📅 Days to Maturity

85–120 days

🧪 Soil pH

Needs 6–7.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

267 days in Colusa County

Growing Tips for Pumpkin in Colusa County

Direct sow Pumpkin outdoors after March 06 in Colusa County when soil has warmed and frost danger has passed.

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

General growing tips

Direct sow on mounds after last frost. Allow 6-10 feet between plants. Slip a board under developing fruit to prevent rot. Harvest when rind is hard and deep in color.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pumpkin in Colusa County, CA?

Colusa County is in Zone 9b with an average last frost of March 6. Plan your Pumpkin planting based on this frost date — see the calendar above for exact timing.

What planting zone is Colusa County, CA?

Colusa County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 6 and first fall frost is November 28.

🌱

Your Colusa County Garden Planner — Free

A 24-page printable planner built for Colusa 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 Colusa 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.