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When to Plant Edamame in Pinal County, AZ

Pinal County, Arizona Zone 9a May

May in Pinal County, Arizona — your action list

Your garden in Pinal County, Arizona is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost February 23
Avg. first frost November 27
Soil temp (4") 66°F
Watering Critical
Pest pressure High
Daylight 13.7 hrs
  1. It's harvest week for edamame

    Taste as you pick. The first ripe produce is the best feedback loop you'll get all season.

Get ahead of June
  • First harvests: edamame

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Edamame are soybeans harvested at the immature green stage for a sweet, nutty snack. They are high in protein and easy to grow in warm climates.

Pinal County, Arizona is in USDA Zone 9a. The average last spring frost is February 23 and the first fall frost is November 27, giving you a growing season of approximately 277 days.

At an elevation of 3,959 feet, Pinal County receives approximately 15.8 inches of rainfall annually with predominantly sandy loam soil. Summer highs average 98°F, so Edamame may need afternoon shade and extra watering during peak heat. Sandy soil warms quickly in spring — great for early planting — but Edamame will need more frequent watering and organic matter to retain nutrients. With low rainfall, drip irrigation is essential for growing Edamame successfully. Mulch heavily to conserve soil moisture.

Pinal County, AZ (Zone 9a) Year-round
277 days
Last Spring Frost February 23
277 growing days
First Fall Frost November 27
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Pinal County Soil Profile

Soil Type

Sandy Loam

Soil pH

7-8.6

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (166 days to spare)
Transplant: Feb 10 🍅 Harvest: Apr 28 – Jun 9
Recommended (50%) ✓ Fits season (158 days to spare)
Transplant: Feb 23 🍅 Harvest: May 11 – Jun 22
Safe Start (90%) ✓ Fits season (146 days to spare)
Transplant: Mar 24 🍅 Harvest: Jun 9 – Jul 21

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 Pinal County

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

Soil pH

Your soil pH (7.0–8.6) is more alkaline than Edamame prefers (6.0–7.0). Add sulfur or peat moss to lower pH.

Soil Texture

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

Drainage

Drainage is adequate for Edamame.

Organic Matter

Organic matter is low (0.7%). Add 2-3 inches of compost before planting Edamame.

How to Plant Edamame

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Succession Planting Edamame

4
successive plantings in your 277-day season

Sow every 8.6 weeks. Last sowing by Aug 19 to harvest before frost.

Plant Water Budget

Plant needs
0.9″/week
Rainfall provides
0.2″/week
You supply
1.1″/week
Watering frequency 2-3 times/week
Season total 2,765 gal / 100 sq ft
Drought risk

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

Monthly Watering Guide for Edamame

Edamame needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.

Month Edamame Needs Rainfall You Supplement Action
Jan 1" 0" ❄️ Dormant
Feb 3.9" 1" 2.9" 🚿 Regular watering
Mar 3.9" 0.8" 3.1" 🚿 Regular watering
Apr 3.9" 0.5" 3.4" 🚿 Regular watering
May 3.9" 0.3" 3.6" 🚿 Regular watering
Jun 3.9" 0.5" 3.4" 🚿 Regular watering
Jul 3.9" 3" 0.9" 💧 Light watering
Aug 3.9" 3.5" 0.4" 💧 Light watering
Sep 3.9" 1.9" 2" 🚿 Regular watering
Oct 3.9" 1.5" 2.4" 🚿 Regular watering
Nov 3.9" 0.8" 3.1" 🚿 Regular watering
Dec 1" 0" ❄️ Dormant

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

Edamame 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.

Edamame needs ~2,056 GDD — county provides 6,533 GDD Excellent fit

Edamame Planting Timeline — Pinal County, AZ

Edamame Planting Calendar

Activity When Date Range
Direct Sow March 2 Mar 2 – Mar 23
Harvest May 18 May 18 – Jun 29

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April
May Harvest
June Harvest
July
August
September
October
November
December
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Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.9"/week · 2-3 times/week

📅 Days to Maturity

75–100 days

🧪 Soil pH

Needs 6–7 · Your soil: too_alkaline

🗺️ USDA Zone

Zone 9a

📆 Growing Season

277 days in Pinal County

Growing Tips for Edamame in Pinal County

Direct sow Edamame outdoors after February 23 in Pinal County when soil has warmed and frost danger has passed.

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

With summer highs reaching 98°F in Pinal County, provide afternoon shade for Edamame and water deeply in the morning.

Common pests for Edamame in this region include bean beetles and aphids. Use row covers early in the season and inspect plants weekly.

Pinal County receives only 16" of rain annually. Edamame needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Direct sow after soil is warm. Do not over-fertilize with nitrogen. Harvest when pods are plump and bright green but before they start to yellow. Steam or boil pods before eating.

Companion Planting

Good Companions

Avoid Planting Near

  • Onion
  • Garlic

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Edamame in Pinal County, AZ?

Pinal County is in Zone 9a with an average last frost of February 23. Plan your Edamame planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pinal County, AZ?

Pinal County, Arizona is in USDA Hardiness Zone 9a. The average last spring frost is February 23 and first fall frost is November 27.

🌱

Your Pinal County Garden Planner — Free

A 24-page printable planner built for Pinal County (Zone 9a). 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 Pinal 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.