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When to Plant Sorrel in Pima County, AZ

Pima County, Arizona Zone 9b May

This month in Pima County, Arizona

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

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 harvesting sorrel

    Don't tug. Use scissors or pruners for clean cuts — torn stems invite disease.

A few tasks this May that'll pay off in June
  • First harvests: sorrel

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Sorrel is a perennial herb with tangy, lemon-flavored arrow-shaped leaves. It is one of the first greens to emerge in spring and is used in soups and salads.

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 Sorrel may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Sorrel will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Sorrel 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 (127 days to spare)
Start indoors: Feb 22 Transplant: Mar 15 🍅 Harvest: Apr 26 – Jun 28
Recommended (50%) ✓ Fits season (124 days to spare)
Start indoors: Mar 4 Transplant: Mar 25 🍅 Harvest: May 6 – Jul 8
Safe Start (90%) ✓ Fits season (117 days to spare)
Start indoors: Apr 7 Transplant: Apr 28 🍅 Harvest: Jun 9 – Aug 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 Pima County

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

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Sorrel prefers (5.5–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Sorrel.

Organic Matter

Organic matter is low (0.9%). Add 2-3 inches of compost before planting Sorrel.

How to Plant Sorrel

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

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

Succession Planting Sorrel

6
successive plantings in your 222-day season

Sow every 4.6 weeks. Last sowing by Sep 10 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

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 Sorrel

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

Month Sorrel 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.

Sorrel 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.

Sorrel needs ~1,362 GDD — county provides 6,049 GDD Excellent fit

Sorrel Planting Timeline — Pima County, AZ

Sorrel Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors March 25 Mar 25 – Apr 8
Direct Sow March 11 Mar 11 – Apr 1
Harvest May 6 May 6 – Jul 8
Fall Sowing September 14 Sep 14 – Sep 28

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1"/week · 2-3 times/week

📅 Days to Maturity

40–60 days

🧪 Soil pH

Needs 5.5–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

222 days in Pima County

Growing Tips for Sorrel in Pima County

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

Sandy soil in Pima County dries quickly — mulch Sorrel 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 Sorrel and water deeply in the morning.

Your generous 222.0-day season in Pima County allows multiple plantings of Sorrel. Sow every 20.0 days for continuous harvest.

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

General growing tips

Direct sow in early spring or fall. Remove flower stalks promptly to encourage leaf production. Divide clumps every 3-4 years. Young leaves have the best flavor.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Sorrel in Pima County, AZ?

Pima County is in Zone 9b with an average last frost of April 1. Plan your Sorrel 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.