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When to Plant Pomegranate in Walla Walla County, WA

Walla Walla County, Washington Zone 7a May

Your May game plan for Walla Walla County, Washington

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

Avg. last frost April 20
Avg. first frost October 15
Soil temp (4") 56°F
Watering High
Pest pressure Low
Daylight 14.8 hrs
  1. Move pomegranate into the garden

    Bring a watering can to the bed. Each transplant gets a drink the moment it's in the ground, not ten minutes later.

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Pomegranates are drought-tolerant shrubs or small trees producing fruits filled with jewel-like, sweet-tart arils. They thrive in hot, dry climates and make excellent hedges.

Walla Walla County, Washington is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 15, giving you a growing season of approximately 178 days.

At an elevation of 3,151 feet, Walla Walla County receives approximately 23.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 85°F, providing good warmth for Pomegranate during the growing season.

Walla Walla County, WA (Zone 7a) Moderate season
178 days
Last Spring Frost April 20
178 growing days
First Fall Frost October 15

Walla Walla County Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: Apr 24
Recommended (50%) ✓ Fits season
Transplant: May 11
Safe Start (90%) ✓ Fits season
Transplant: Jun 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 Walla Walla County

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

Soil pH

Your soil pH (5.2–6.4) overlaps with Pomegranate's range (5.5–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Walla Walla County is excellent for Pomegranate — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (4.2%) — Pomegranate will thrive.

How to Plant Pomegranate

120"
Between Plants
144"
Between Rows

Plant Water Budget

Plant needs
0.5″/week
Rainfall provides
0.6″/week
Watering frequency Natural rainfall sufficient
Season total 0 gal / 100 sq ft

Monthly Watering Guide for Pomegranate

Pomegranate needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Pomegranate Needs Rainfall You Supplement Action
Jan 2.9" 0" ❄️ Dormant
Feb 2.7" 0" ❄️ Dormant
Mar 2.3" 0" ❄️ Dormant
Apr 2.2" 1.7" 0.5" 💧 Light watering
May 2.2" 1.5" 0.7" 💧 Light watering
Jun 2.2" 1" 1.2" 🚿 Regular watering
Jul 2.2" 0.4" 1.8" 🚿 Regular watering
Aug 2.2" 0.5" 1.7" 🚿 Regular watering
Sep 2.2" 0.9" 1.3" 🚿 Regular watering
Oct 2.2" 2.2" 0" ✅ Rainfall sufficient
Nov 3.7" 0" ❄️ Dormant
Dec 3.8" 0" ❄️ Dormant

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

Pomegranate 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.

Pomegranate needs ~12,547 GDD — county provides 2,447 GDD May not mature

Pomegranate Planting Timeline — Walla Walla County, WA

Pomegranate Planting Calendar

Activity When Date Range
Transplant Outdoors May 11 May 11 – May 25

· 120" apart · Rows 144" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

730–1095 days

🧪 Soil pH

Needs 5.5–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 7a

📆 Growing Season

178 days in Walla Walla County

Growing Tips for Pomegranate in Walla Walla County

Direct sow Pomegranate outdoors after April 20 in Walla Walla County when soil has warmed and frost danger has passed.

Your 178.0-day growing season in Walla Walla County is tight for Pomegranate (730.0-1095.0 days to maturity). Start indoors and choose early-maturing varieties.

Walla Walla County receives only 24" of rain annually. Pomegranate needs consistent moisture — install drip irrigation or water deeply 2-3 times per week.

General growing tips

Plant in full sun with well-drained soil. Water deeply but infrequently. Prune to maintain shape and remove suckers. Harvest when fruits have developed full color and sound metallic when tapped.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Pomegranate in Walla Walla County, WA?

Walla Walla County is in Zone 7a with an average last frost of April 20. Plan your Pomegranate planting based on this frost date — see the calendar above for exact timing.

What planting zone is Walla Walla County, WA?

Walla Walla County, Washington is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 15.

🌱

Your Walla Walla County Garden Planner — Free

A 24-page printable planner built for Walla Walla County (Zone 7a). 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 Walla Walla County, WA. 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.