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When to Plant New Zealand Spinach in Pima County, AZ

Pima County, Arizona Zone 9b May

Your May planting checklist for Pima County, Arizona

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

Avg. last frost April 1
Avg. first frost November 9
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.6 hrs
  1. Start new zealand spinach under lights

    A seed-starting mix and a sunny window (or a grow light) are all you need. Keep soil warm — around 70°F — for fast germination.

Coming up in June — start thinking about
  • First harvests: new zealand spinach

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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.

Pima County, Arizona is in USDA Zone 9b. The average last spring frost is April 1 and the first fall frost is November 9, giving you a growing season of approximately 222 days.

At an elevation of 4,327 feet, Pima County receives approximately 14.4 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 103°F, so New Zealand Spinach may need afternoon shade and extra watering during peak heat. 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. With low rainfall, drip irrigation is essential for growing New Zealand Spinach successfully. Mulch heavily to conserve soil moisture.

Pima County, AZ (Zone 9b) Long season
222 days
Last Spring Frost April 1
222 growing days
First Fall Frost November 9

Pima County Soil Profile

Soil Type

Sandy Loam

Soil pH

6.8-8.3

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (134 days to spare)
Start indoors: Feb 8 Transplant: Mar 29 🍅 Harvest: May 24 – Jun 21
Recommended (50%) ✓ Fits season (131 days to spare)
Start indoors: Feb 18 Transplant: Apr 8 🍅 Harvest: Jun 3 – Jul 1
Safe Start (90%) ✓ Fits season (124 days to spare)
Start indoors: Mar 24 Transplant: May 12 🍅 Harvest: Jul 7 – Aug 4

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 Pima County

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

Soil pH

Your soil pH (6.8–8.3) is more alkaline than New Zealand Spinach prefers (6.0–7.5). Add sulfur or peat moss to lower pH.

Soil Texture

Sandy soil in Pima 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 low (0.9%). Add 2-3 inches of compost before planting New Zealand Spinach.

How to Plant New Zealand Spinach

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

Succession Planting New Zealand Spinach

4
successive plantings in your 222-day season

Sow every 6.3 weeks. Last sowing by Aug 31 to harvest before frost.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.3″/week
You supply
1.2″/week
Watering frequency 2-3 times/week
Season total 2,436 gal / 100 sq ft
Drought risk

Water stress score is 10/10 — 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 0.9" 0" ❄️ Dormant
Feb 0.8" 0" ❄️ Dormant
Mar 0.7" 0" ❄️ Dormant
Apr 4.3" 0.5" 3.8" 🚿 Regular watering
May 4.3" 0.4" 3.9" 🚿 Regular watering
Jun 4.3" 0.5" 3.8" 🚿 Regular watering
Jul 4.3" 2.7" 1.6" 💧 Light watering
Aug 4.3" 3.2" 1.1" 💧 Light watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 1.4" 2.9" 🚿 Regular watering
Nov 4.3" 0.7" 3.6" 🚿 Regular watering
Dec 0.9" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Nov in Pima 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 ~1,703 GDD — county provides 6,049 GDD Excellent fit

New Zealand Spinach Planting Timeline — Pima County, AZ

New Zealand Spinach Planting Calendar

Activity When Date Range
Start Indoors February 18 Feb 18 – Mar 4
Transplant Outdoors April 8 Apr 8 – Apr 22
Direct Sow April 1 Apr 1 – Apr 22
Harvest June 3 Jun 3 – Jul 1

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

Month-by-Month Timeline

MonthActivities
January
February Start Indoors
March Start Indoors
April Transplant Outdoors Direct Sow
May
June Harvest
July Harvest
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: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

222 days in Pima County

Growing Tips for New Zealand Spinach in Pima County

Direct sow New Zealand Spinach outdoors after April 01 in Pima County when soil has warmed and frost danger has passed.

Sandy soil in Pima 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.

With summer highs reaching 103°F in Pima County, provide afternoon shade for New Zealand Spinach and water deeply in the morning.

Pima County receives only 14" of rain annually. New Zealand Spinach needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

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 Pima County, AZ?

Pima County is in Zone 9b with an average last frost of April 1. Plan your New Zealand Spinach planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pima County, AZ?

Pima County, Arizona is in USDA Hardiness Zone 9b. The average last spring frost is April 1 and first fall frost is November 9.

🌱

Your Pima County Garden Planner — Free

A 24-page printable planner built for Pima 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 Pima County, AZ. 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.