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When to Plant Shallot in Butte County, CA

Butte County, California Zone 9b May

Your May planting checklist for Butte County, California

A quick May briefing for Butte County, California gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 20
Avg. first frost November 10
Soil temp (4") 75°F
Watering Critical
Pest pressure High
Daylight 14.2 hrs
  1. Time to start shallot inside

    You're about 24 weeks out from your last frost — the perfect window to get these germinating indoors.

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Shallots are a gourmet allium prized for their complex, sweet, and mild flavor. Each bulb multiplies into a cluster, making them easy and rewarding to grow.

Butte County, California is in USDA Zone 9b. The average last spring frost is April 20 and the first fall frost is November 10, giving you a growing season of approximately 204 days.

At an elevation of 144 feet, Butte County receives approximately 44.8 inches of rainfall annually with predominantly loam soil. Summer highs average 90°F, providing good warmth for Shallot during the growing season.

Butte County, CA (Zone 9b) Long season
204 days
Last Spring Frost April 20
204 growing days
First Fall Frost November 10

Butte 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 (59 days to spare)
Start indoors: Feb 26 Transplant: Mar 26 🍅 Harvest: Jun 25 – Aug 13
Recommended (50%) ✓ Fits season (64 days to spare)
Start indoors: Mar 23 Transplant: Apr 20 🍅 Harvest: Jul 20 – Sep 7
Safe Start (90%) ✓ Fits season (64 days to spare)
Start indoors: Apr 26 Transplant: May 24 🍅 Harvest: Aug 23 – Oct 11

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 Butte County

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

Soil pH

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

Soil Texture

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

Drainage

Drainage is adequate for Shallot.

Organic Matter

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

How to Plant Shallot

1"
Planting Depth
6"
Between Plants
12"
Between Rows

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

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.9″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 823 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Shallot

Shallot needs approximately 1 inches of water per week (4.3" per month). Here's how your county's rainfall compares month by month.

Month Shallot Needs Rainfall You Supplement Action
Jan 9.7" 0" ❄️ Dormant
Feb 9.9" 0" ❄️ Dormant
Mar 6.9" 0" ❄️ Dormant
Apr 4.3" 3" 1.3" 💧 Light watering
May 4.3" 1.1" 3.2" 🚿 Regular watering
Jun 4.3" 0.2" 4.1" 🚿 Regular watering
Jul 4.3" 0" 4.3" 🚿 Regular watering
Aug 4.3" 0" 4.3" 🚿 Regular watering
Sep 4.3" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 2.1" 2.2" 🚿 Regular watering
Nov 4.3" 3.7" 0.6" 💧 Light watering
Dec 7.8" 0" ❄️ Dormant

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

Shallot 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.

Shallot needs ~1,838 GDD — county provides 3,570 GDD Excellent fit

Shallot Planting Timeline — Butte County, CA

Shallot Planting Calendar

Activity When Date Range
Start Indoors March 23 Mar 23 – Apr 6
Transplant Outdoors April 20 Apr 20 – May 4
Direct Sow March 30 Mar 30 – Apr 20
Harvest July 20 Jul 20 – Sep 7
Fall Sowing September 15 Sep 15 – Sep 29

Plant 1" deep · 6" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 1-2 times/week

📅 Days to Maturity

90–120 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

204 days in Butte County

Growing Tips for Shallot in Butte County

Direct sow Shallot outdoors after April 20 in Butte County when soil has warmed and frost danger has passed.

Common pests for Shallot in this region include onion maggots and thrips. Use row covers early in the season and inspect plants weekly.

General growing tips

Plant sets in fall for spring harvest or early spring for summer harvest. Mulch heavily if overwintering. Harvest when tops brown and dry, then cure for storage.

Companion Planting

Good Companions

Avoid Planting Near

  • Peas
  • Green Beans

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Shallot in Butte County, CA?

Butte County is in Zone 9b with an average last frost of April 20. Plan your Shallot planting based on this frost date — see the calendar above for exact timing.

What planting zone is Butte County, CA?

Butte County, California is in USDA Hardiness Zone 9b. The average last spring frost is April 20 and first fall frost is November 10.

🌱

Your Butte County Garden Planner — Free

A 24-page printable planner built for Butte 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 Butte 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.