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When to Plant Jicama in Pacific County, WA

Pacific County, Washington Zone 9a May

What to do in May

Welcome to May in Zone 9a. These are the moves that will have the biggest impact on your growing season.

Avg. last frost April 18
Avg. first frost October 29
Soil temp (4") 71°F
Watering Moderate
Pest pressure High
Daylight 14.8 hrs
  1. Indoor seed-starting week for jicama

    These need a head start before your last frost (April 18). Sow into cells now so you're ready to transplant in a few weeks.

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Jicama is a tropical legume grown for its crisp, sweet, starchy root. It requires a very long, warm growing season but produces a refreshing, water chestnut-like tuber.

Pacific County, Washington is in USDA Zone 9a. The average last spring frost is April 18 and the first fall frost is October 29, giving you a growing season of approximately 194 days.

At an elevation of 14 feet, Pacific County receives approximately 47.4 inches of rainfall annually with predominantly silt loam soil. Summer highs average 86°F, providing good warmth for Jicama during the growing season.

Pacific County, WA (Zone 9a) Moderate season
194 days
Last Spring Frost April 18
194 growing days
First Fall Frost October 29
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Pacific County Soil Profile

Soil Type

Silt Loam

Soil pH

5.6-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 22 Transplant: Apr 12 🍅 Harvest: Aug 16 – Oct 25
Recommended (50%) ✗ May not fit
Start indoors: Mar 7 Transplant: Apr 25 🍅 Harvest: Aug 29 – Nov 7
Safe Start (90%) ✓ Fits season (4 days to spare)
Start indoors: Mar 28 Transplant: May 16 🍅 Harvest: Sep 19 – Nov 28

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 Pacific County

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

Soil pH

Your soil pH (5.6–6.2) is more acidic than Jicama prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

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

How to Plant Jicama

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

Plant Water Budget

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

Monthly Watering Guide for Jicama

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

Month Jicama Needs Rainfall You Supplement Action
Jan 7.2" 0" ❄️ Dormant
Feb 5" 0" ❄️ Dormant
Mar 4.5" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 1.8" 2.5" 🚿 Regular watering
Jul 4.3" 0.9" 3.4" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 1.7" 2.6" 🚿 Regular watering
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 8" 0" ❄️ Dormant
Dec 6.7" 0" ❄️ Dormant

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

Jicama 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.

Jicama needs ~2,175 GDD — county provides 2,813 GDD Good fit

Jicama Planting Timeline — Pacific County, WA

Jicama Planting Calendar

Activity When Date Range
Start Indoors March 7 Mar 7 – Mar 21
Transplant Outdoors April 25 Apr 25 – May 9
Direct Sow April 18 Apr 18 – May 9
Harvest August 29 Aug 29 – Nov 7

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

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

120–180 days

🧪 Soil pH

Needs 6–7.5 · Your soil: too_acidic

🗺️ USDA Zone

Zone 9a

📆 Growing Season

194 days in Pacific County

Growing Tips for Jicama in Pacific County

Direct sow Jicama outdoors after April 18 in Pacific County when soil has warmed and frost danger has passed.

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

General growing tips

Start seeds indoors 8-10 weeks before last frost. Pinch off flowers to direct energy to root development. Harvest before first frost when roots are 3-6 inches across.

Companion Planting

Good Companions

Avoid Planting Near

  • Fennel

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Jicama in Pacific County, WA?

Pacific County is in Zone 9a with an average last frost of April 18. Plan your Jicama planting based on this frost date — see the calendar above for exact timing.

What planting zone is Pacific County, WA?

Pacific County, Washington is in USDA Hardiness Zone 9a. The average last spring frost is April 18 and first fall frost is October 29.

🌱

Your Pacific County Garden Planner — Free

A 24-page printable planner built for Pacific 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 Pacific 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.