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When to Plant New Zealand Spinach in Sonoma County, CA

Sonoma County, California Zone 9b May

This month in Sonoma County, California

We've pulled the most time-sensitive tasks for Sonoma 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") 76°F
Watering Critical
Pest pressure High
Daylight 14.1 hrs
  1. Collect new zealand spinach at their peak

    Morning harvests are best — cooler temperatures mean crisper produce and longer fridge life.

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New Zealand spinach is a heat-tolerant ground-cover plant with thick, triangular leaves that taste similar to true spinach. It thrives in hot weather when regular spinach bolts.

Sonoma 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 91 feet, Sonoma County receives approximately 31.1 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 90°F, providing good warmth for New Zealand Spinach during the growing season. Sandy soil warms quickly in spring — great for early planting — but New Zealand Spinach will need more frequent watering and organic matter to retain nutrients.

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

Sonoma County Soil Profile

Soil Type

Sandy Loam

Soil pH

5.9-7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (194 days to spare)
Start indoors: Dec 30 Transplant: Feb 17 🍅 Harvest: Apr 14 – May 12
Recommended (50%) ✓ Fits season (182 days to spare)
Start indoors: Jan 15 Transplant: Mar 5 🍅 Harvest: Apr 30 – May 28
Safe Start (90%) ✓ Fits season (168 days to spare)
Start indoors: Feb 19 Transplant: Apr 9 🍅 Harvest: Jun 4 – Jul 2

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 Sonoma County

How your county's soil matches New Zealand Spinach's growing requirements.

Soil pH

Your soil pH (5.9–7.0) overlaps with New Zealand Spinach's range (6.0–7.5), though not a perfect match.

Soil Texture

Sandy soil in Sonoma County warms quickly in spring but drains fast. New Zealand Spinach will need more frequent watering and regular compost additions to retain nutrients.

Drainage

Drainage is adequate for New Zealand Spinach.

Organic Matter

Organic matter is moderate (2.5%). Annual compost additions will help New Zealand Spinach.

How to Plant New Zealand Spinach

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

Succession Planting New Zealand Spinach

5
successive plantings in your 273-day season

Sow every 6.3 weeks. Last sowing by Sep 17 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
1.0″/week
Watering frequency 2-3 times/week
Season total 2,409 gal / 100 sq ft
Drought risk

Water stress score is 6/10 — consider drought-tolerant varieties and mulching

Monthly Watering Guide for New Zealand Spinach

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

Month New Zealand Spinach Needs Rainfall You Supplement Action
Jan 6.2" 0" ❄️ Dormant
Feb 4.3" 6.8" 0" ✅ Rainfall sufficient
Mar 4.3" 5.2" 0" ✅ Rainfall sufficient
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" 0.4" 3.9" 🚿 Regular watering
Oct 4.3" 1.3" 3" 🚿 Regular watering
Nov 4.3" 2.7" 1.6" 💧 Light watering
Dec 5.2" 0" ❄️ Dormant

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

New Zealand Spinach 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.

New Zealand Spinach needs ~1,094 GDD — county provides 4,795 GDD Excellent fit

New Zealand Spinach Planting Timeline — Sonoma County, CA

New Zealand Spinach Planting Calendar

Activity When Date Range
Start Indoors January 15 Jan 15 – Jan 29
Transplant Outdoors March 5 Mar 5 – Mar 19
Direct Sow February 26 Feb 26 – Mar 19
Harvest April 30 Apr 30 – May 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

55–70 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9b

📆 Growing Season

273 days in Sonoma County

Growing Tips for New Zealand Spinach in Sonoma County

Direct sow New Zealand Spinach outdoors after February 26 in Sonoma County when soil has warmed and frost danger has passed.

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

General growing tips

Soak seeds overnight before planting. Direct sow after last frost. Pinch growing tips regularly to encourage bushy growth and tender new leaves.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant New Zealand Spinach in Sonoma County, CA?

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

What planting zone is Sonoma County, CA?

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

🌱

Your Sonoma County Garden Planner — Free

A 24-page printable planner built for Sonoma 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 Sonoma 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.