Blog

When to Plant Radicchio in Sutter County, CA

Sutter County, California Zone 9b May

This month in Sutter County, California

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

Avg. last frost March 4
Avg. first frost November 26
Soil temp (4") 76°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Start harvesting radicchio

    Check every 1–2 days. Many of these get tough or go to seed if you wait too long.

June will be here before you know it — start on
  • First harvests: radicchio

Instant PDF download. No spam, unsubscribe any time.

Radicchio is an Italian chicory with stunning red and white leaves and a pleasantly bitter flavor. It forms tight heads and is used in salads, grilled, or braised.

Sutter County, California is in USDA Zone 9b. The average last spring frost is March 4 and the first fall frost is November 26, giving you a growing season of approximately 267 days.

At an elevation of 484 feet, Sutter County receives approximately 21.4 inches of rainfall annually with predominantly loam soil. Summer highs average 88°F, providing good warmth for Radicchio during the growing season.

Sutter County, CA (Zone 9b) Long season
267 days
Last Spring Frost March 4
267 growing days
First Fall Frost November 26

Sutter County Soil Profile

Soil Type

Loam

Soil pH

6.8-7.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (181 days to spare)
Start indoors: Jan 10 Transplant: Feb 7 🍅 Harvest: Apr 11 – May 16
Recommended (50%) ✓ Fits season (169 days to spare)
Start indoors: Feb 4 Transplant: Mar 4 🍅 Harvest: May 6 – Jun 10
Safe Start (90%) ✓ Fits season (136 days to spare)
Start indoors: Mar 30 Transplant: Apr 27 🍅 Harvest: Jun 29 – Aug 3

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 Sutter County

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

Soil pH

Your soil pH (6.8–7.7) is more alkaline than Radicchio prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Radicchio.

Organic Matter

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

How to Plant Radicchio

0.5"
Planting Depth
6"
Between Plants
12"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Radicchio

5
successive plantings in your 267-day season

Sow every 6.9 weeks. Last sowing by Sep 07 to harvest before frost.

For a dedicated fall crop, sow by Oct 01.

Plant Water Budget

Plant needs
0.7″/week
Rainfall provides
0.3″/week
You supply
0.7″/week
Watering frequency 1-2 times/week
Season total 1,635 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Radicchio

Radicchio needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Radicchio Needs Rainfall You Supplement Action
Jan 4.6" 0" ❄️ Dormant
Feb 4.2" 0" ❄️ Dormant
Mar 3" 3.7" 0" ✅ Rainfall sufficient
Apr 3" 1.4" 1.6" 🚿 Regular watering
May 3" 0.6" 2.4" 🚿 Regular watering
Jun 3" 0.1" 2.9" 🚿 Regular watering
Jul 3" 0" 3" 🚿 Regular watering
Aug 3" 0" 3" 🚿 Regular watering
Sep 3" 0.2" 2.8" 🚿 Regular watering
Oct 3" 0.9" 2.1" 🚿 Regular watering
Nov 3" 1.8" 1.2" 💧 Light watering
Dec 3.8" 0" ❄️ Dormant

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

Radicchio 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.

Radicchio needs ~1,120 GDD — county provides 4,272 GDD Excellent fit

Radicchio Planting Timeline — Sutter County, CA

Radicchio Planting Calendar

Activity When Date Range
Start Indoors February 4 Feb 4 – Feb 18
Transplant Outdoors March 4 Mar 4 – Mar 18
Direct Sow February 11 Feb 11 – Mar 4
Harvest May 6 May 6 – Jun 10
Fall Sowing October 1 Oct 1 – Oct 15

Plant 0.5" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · 1-2 times/week

📅 Days to Maturity

60–80 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

267 days in Sutter County

Growing Tips for Radicchio in Sutter County

Direct sow Radicchio outdoors after March 04 in Sutter County when soil has warmed and frost danger has passed.

Common pests for Radicchio in this region include aphids and slugs. Use row covers early in the season and inspect plants weekly.

General growing tips

Start in late summer for fall harvest. The red color develops with cool nights and light frost. Harvest when heads are firm and compact.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radicchio in Sutter County, CA?

Sutter County is in Zone 9b with an average last frost of March 4. Plan your Radicchio planting based on this frost date — see the calendar above for exact timing.

What planting zone is Sutter County, CA?

Sutter County, California is in USDA Hardiness Zone 9b. The average last spring frost is March 4 and first fall frost is November 26.

🌱

Your Sutter County Garden Planner — Free

A 24-page printable planner built for Sutter 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.

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 Sutter 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.