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When to Plant Chives in Marin County, CA

Marin County, California Zone 9b May

Your May planting checklist for Marin County, California

We've pulled the most time-sensitive tasks for Marin County, California this May and put them front and centre. Tackle them in order.

Avg. last frost February 26
Avg. first frost November 26
Soil temp (4") 79°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Start harvesting chives

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

Before June arrives, get these ready
  • First harvests: chives

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Chives are a hardy perennial herb with a mild onion flavor and attractive purple pom-pom flowers. They are one of the easiest herbs to grow and maintain.

Marin County, California is in USDA Zone 9b. The average last spring frost is February 26 and the first fall frost is November 26, giving you a growing season of approximately 273 days.

At an elevation of 302 feet, Marin County receives approximately 36 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 81°F, so choose short-season varieties of Chives to ensure they mature before fall. Sandy soil warms quickly in spring — great for early planting — but Chives will need more frequent watering and organic matter to retain nutrients.

Marin County, CA (Zone 9b) Year-round
273 days
Last Spring Frost February 26
273 growing days
First Fall Frost November 26

Marin County Soil Profile

Soil Type

Sandy Loam

Soil pH

6-6.9

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (145 days to spare)
Transplant: Feb 17 🍅 Harvest: Apr 21 – Jun 30
Recommended (50%) ✓ Fits season (133 days to spare)
Transplant: Mar 5 🍅 Harvest: May 7 – Jul 16
Safe Start (90%) ✓ Fits season (119 days to spare)
Transplant: Apr 9 🍅 Harvest: Jun 11 – Aug 20

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 Marin County

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

Soil pH

Your soil pH (6.0–6.9) is within Chives's preferred range (6.0–7.0).

Soil Texture

Sandy soil in Marin County warms quickly in spring but drains fast. Chives will need more frequent watering and regular compost additions to retain nutrients.

Organic Matter

Organic matter is moderate (2.3%). Annual compost additions will help Chives.

How to Plant Chives

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Chives

5
successive plantings in your 273-day season

Sow every 6.9 weeks. Last sowing by Aug 28 to harvest before frost.

Plant Water Budget

Plant needs
0.4″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Chives

Chives needs approximately 0.4 inches of water per week (1.7" per month). Here's how your county's rainfall compares month by month.

Month Chives Needs Rainfall You Supplement Action
Jan 7.2" 0" ❄️ Dormant
Feb 1.7" 6.5" 0" ✅ Rainfall sufficient
Mar 1.7" 6.2" 0" ✅ Rainfall sufficient
Apr 1.7" 2.7" 0" ✅ Rainfall sufficient
May 1.7" 1" 0.7" 💧 Light watering
Jun 1.7" 0.2" 1.5" 🚿 Regular watering
Jul 1.7" 0" 1.7" 🚿 Regular watering
Aug 1.7" 0" 1.7" 🚿 Regular watering
Sep 1.7" 0.4" 1.3" 🚿 Regular watering
Oct 1.7" 1.4" 0.3" 💧 Light watering
Nov 1.7" 3.5" 0" ✅ Rainfall sufficient
Dec 6.9" 0" ❄️ Dormant

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

Chives 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.

Chives needs ~806 GDD — county provides 2,945 GDD Excellent fit

Chives Planting Timeline — Marin County, CA

Chives Planting Calendar

Activity When Date Range
Transplant Outdoors March 5 Mar 5 – Mar 19
Harvest May 7 May 7 – Jul 16

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.4"/week · Natural rainfall sufficient

📅 Days to Maturity

60–90 days

🧪 Soil pH

Needs 6–7 · Your soil: ideal

🗺️ USDA Zone

Zone 9b

📆 Growing Season

273 days in Marin County

Growing Tips for Chives in Marin County

Direct sow Chives outdoors after February 26 in Marin County when soil has warmed and frost danger has passed.

Sandy soil in Marin County dries quickly — mulch Chives with 2-3 inches of straw and water deeply 2-3 times per week rather than lightly every day.

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

General growing tips

Start from seed or divisions in spring. Cut back to 2 inches after flowering to encourage fresh growth. Both the leaves and flowers are edible and delicious.

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 Chives in Marin County, CA?

Marin County is in Zone 9b with an average last frost of February 26. Plan your Chives planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marin County, CA?

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

🌱

Your Marin County Garden Planner — Free

A 24-page printable planner built for Marin 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 Marin 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.