Blog

When to Plant Ginger in King County, WA

King County, Washington Zone 9a May

Your May gardening checklist

Your King County, Washington garden is entering a new phase. Here's what's on the schedule for May and why each task matters now.

Avg. last frost April 7
Avg. first frost October 30
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.9 hrs
  1. Time to start ginger inside

    These need a head start before your last frost (April 7). Sow into cells now so you're ready to transplant in a few weeks.

Instant PDF download. No spam, unsubscribe any time.

Ginger is a tropical plant grown for its pungent, spicy rhizome used worldwide in cooking and medicine. It requires a long, warm, humid growing season.

King County, Washington is in USDA Zone 9a. The average last spring frost is April 7 and the first fall frost is October 30, giving you a growing season of approximately 206 days.

At an elevation of 258 feet, King County receives approximately 37.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 89°F, providing good warmth for Ginger during the growing season.

King County, WA (Zone 9a) Long season
206 days
Last Spring Frost April 7
206 growing days
First Fall Frost October 30

King County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (261 days to spare)
Start indoors: Feb 10 Transplant: Mar 31 🍅 Harvest: Dec 1 – Jan 26
Recommended (50%) ✓ Fits season (263 days to spare)
Start indoors: Feb 24 Transplant: Apr 14 🍅 Harvest: Dec 15 – Feb 9
Safe Start (90%) ✓ Fits season (242 days to spare)
Start indoors: Apr 8 Transplant: May 27 🍅 Harvest: Jan 27 – Mar 24

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 King County

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

Soil pH

Your soil pH (5.7–6.4) is within Ginger's preferred range (5.5–6.5).

Soil Texture

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

Organic Matter

Organic matter is excellent (5.5%) — Ginger will thrive.

How to Plant Ginger

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

Plant Water Budget

Plant needs
1.5″/week
Rainfall provides
0.8″/week
You supply
0.7″/week
Watering frequency 2-3 times/week
Season total 1,345 gal / 100 sq ft

Monthly Watering Guide for Ginger

Ginger needs approximately 1.5 inches of water per week (6.5" per month). Here's how your county's rainfall compares month by month.

Month Ginger Needs Rainfall You Supplement Action
Jan 5.9" 0" ❄️ Dormant
Feb 4.5" 0" ❄️ Dormant
Mar 3.4" 0" ❄️ Dormant
Apr 6.5" 2.9" 3.6" 🚿 Regular watering
May 6.5" 2" 4.5" 🚿 Regular watering
Jun 6.5" 1.3" 5.2" 🚿 Regular watering
Jul 6.5" 0.6" 5.9" 🚿 Regular watering
Aug 6.5" 0.7" 5.8" 🚿 Regular watering
Sep 6.5" 1.6" 4.9" 🚿 Regular watering
Oct 6.5" 3.4" 3.1" 💧 Light watering
Nov 5.6" 0" ❄️ Dormant
Dec 5.7" 0" ❄️ Dormant

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

Ginger 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.

Ginger needs ~4,522 GDD — county provides 3,450 GDD May not mature

Ginger Planting Timeline — King County, WA

Ginger Planting Calendar

Activity When Date Range
Start Indoors February 24 Feb 24 – Mar 10
Transplant Outdoors April 14 Apr 14 – Apr 28
Direct Sow April 7 Apr 7 – Apr 28
Harvest December 15 Dec 15 – Feb 9

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

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Partial Shade (3-6 hours)

💧 Water

1.5"/week · 2-3 times/week

📅 Days to Maturity

240–300 days

🧪 Soil pH

Needs 5.5–6.5 · Your soil: ideal

🗺️ USDA Zone

Zone 9a

📆 Growing Season

206 days in King County

Growing Tips for Ginger in King County

Direct sow Ginger outdoors after April 07 in King County when soil has warmed and frost danger has passed.

Your 206.0-day growing season in King County is tight for Ginger (240.0-300.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant rhizome pieces with buds 2 inches deep in spring. Keep soil consistently moist but not waterlogged. In cold climates, grow in containers and bring indoors before frost.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Ginger in King County, WA?

King County is in Zone 9a with an average last frost of April 7. Plan your Ginger planting based on this frost date — see the calendar above for exact timing.

What planting zone is King County, WA?

King County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is April 7 and first fall frost is October 30.

🌱

Your King County Garden Planner — Free

A 24-page printable planner built for King 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.

Instant PDF download. No spam, unsubscribe any time.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for King 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.