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When to plant Mitsuba in Pima County, AZ

Aim to plant Mitsuba in Pima County on or after March 11; the window stays open through April 1. Pima County's 222-day frost-free season gives you enough for a full main crop and a short fall succession. A second sowing from September 14 to September 28 extends the harvest into fall.

When to Plant Mitsuba in Pima County, AZ

Pima County, Arizona Zone 9b July

Top priorities for Pima County, Arizona gardeners in July

July 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") 84°F
Watering High
Pest pressure High
Daylight 13.9 hrs
  1. It's harvest week for mitsuba

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

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Mitsuba (Japanese parsley) is a shade-loving herb with trefoil leaves and a mild celery-parsley flavor. It is essential in Japanese cuisine for soups, salads, and garnishes.

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 Mitsuba may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Mitsuba will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Mitsuba 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

Mitsuba Planting Risk Windows

Early Start (70% safe) ✓ Fits season (120 days to spare)
Start indoors: Feb 22 Transplant: Mar 15 🍅 Harvest: May 10 – Jul 5
Recommended (50%) ✓ Fits season (117 days to spare)
Start indoors: Mar 4 Transplant: Mar 25 🍅 Harvest: May 20 – Jul 15
Safe Start (90%) ✓ Fits season (110 days to spare)
Start indoors: Apr 7 Transplant: Apr 28 🍅 Harvest: Jun 23 – Aug 18

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 Mitsuba's growing requirements.

Soil pH

Your soil pH (6.8–8.3) is more alkaline than Mitsuba prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Mitsuba.

Organic Matter

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

How to Plant Mitsuba

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 Mitsuba

5
successive plantings in your 222-day season

Sow every 5.7 weeks. Last sowing by Aug 31 to harvest before frost.

For a dedicated fall crop, sow by Sep 14.

Mitsuba 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 Mitsuba

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

Month Mitsuba 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.

Mitsuba 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.

Mitsuba needs ~1,635 GDD — county provides 6,049 GDD Excellent fit

Mitsuba Planting Timeline — Pima County, AZ

Mitsuba 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 20 May 20 – Jul 15
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

50–70 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9b

📆 Growing Season

222 days in Pima County

Growing Tips for Mitsuba in Pima County

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

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

Common pests for Mitsuba in this region include carrot rust fly and parsleyworm. Use row covers early in the season and inspect plants weekly.

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

General growing tips

Direct sow or start indoors in partial shade. Mitsuba prefers cool, moist conditions. Harvest outer stems as needed. Self-sows readily in shaded garden areas.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Mitsuba in Pima County, AZ?

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

When should I plant Mitsuba in Pima County, AZ?

In Pima County, AZ, plant Mitsuba after the last frost (around April 1) and before the first frost (around November 9). Best results when soil holds above 50°F.

What growing zone is Pima County, AZ for Mitsuba?

Pima County sits in USDA Zone 9b. Mitsuba grows reliably in zones 4a through 9b, so it's a good fit here.

Can Mitsuba grow in Pima County's climate?

Yes — Mitsuba grows well in Pima County's temperate climate. Pima County averages a 222-day frost-free season, with last frost around April 1 and first frost around November 9.

🌱

Your Pima County Garden Planner — Free

A 22-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: July 2026.

Sources & credits

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