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When to Plant Jicama in Josephine County, OR

Josephine County, Oregon Zone 8b May

May in Josephine County, Oregon — your action list

A quick May briefing for Josephine County, Oregon gardeners — what's urgent, what's next, and what can wait.

Avg. last frost April 22
Avg. first frost October 20
Soil temp (4") 69°F
Watering High
Pest pressure High
Daylight 14.4 hrs
  1. Move jicama from tray to bed

    Water the tray well an hour before you transplant. Roots slide out cleanly and settle in faster.

Coming up in June — start thinking about
  • Starting indoors: jicama

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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.

Josephine County, Oregon is in USDA Zone 8b. The average last spring frost is April 22 and the first fall frost is October 20, giving you a growing season of approximately 181 days.

At an elevation of 340 feet, Josephine County receives approximately 52.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 90°F, providing good warmth for Jicama during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Jicama root diseases.

Josephine County, OR (Zone 8b) Moderate season
181 days
Last Spring Frost April 22
181 growing days
First Fall Frost October 20

Josephine County Soil Profile

Soil Type

Silt Loam

Soil pH

5.7-6.2

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Start indoors: Feb 19 Transplant: Apr 23 🍅 Harvest: Aug 27 – Nov 5
Recommended (50%) ✗ May not fit
Start indoors: Mar 4 Transplant: May 6 🍅 Harvest: Sep 9 – Nov 18
Safe Start (90%) ✗ May not fit
Start indoors: Mar 24 Transplant: May 26 🍅 Harvest: Sep 29 – Dec 8

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 Josephine County

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

Soil pH

Your soil pH (5.7–6.2) is more acidic than Jicama prefers (6.0–7.5). Add garden lime to raise pH.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.4%) — 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
1.2″/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 8.4" 0" ❄️ Dormant
Feb 6.6" 0" ❄️ Dormant
Mar 6.2" 0" ❄️ Dormant
Apr 4.3" 3.6" 0.7" 💧 Light watering
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 0.8" 3.5" 🚿 Regular watering
Aug 4.3" 0.9" 3.4" 🚿 Regular watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 4.4" 0" ✅ Rainfall sufficient
Nov 7.4" 0" ❄️ Dormant
Dec 8.2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Josephine 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 ~2,625 GDD — county provides 3,167 GDD Good fit

Jicama Planting Timeline — Josephine County, OR

Jicama Planting Calendar

Activity When Date Range
Start Indoors March 4 Mar 4 – Mar 18
Transplant Outdoors May 6 May 6 – May 20
Direct Sow April 29 Apr 29 – May 20
Harvest September 9 Sep 9 – Nov 18

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

Month-by-Month Timeline

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

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 8b

📆 Growing Season

181 days in Josephine County

Growing Tips for Jicama in Josephine County

Direct sow Jicama outdoors after April 22 in Josephine County when soil has warmed and frost danger has passed.

Your 181.0-day growing season in Josephine County is tight for Jicama (120.0-180.0 days to maturity). Start indoors and choose early-maturing varieties.

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 Josephine County, OR?

Josephine County is in Zone 8b with an average last frost of April 22. Plan your Jicama planting based on this frost date — see the calendar above for exact timing.

What planting zone is Josephine County, OR?

Josephine County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 22 and first fall frost is October 20.

🌱

Your Josephine County Garden Planner — Free

A 24-page printable planner built for Josephine County (Zone 8b). 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 Josephine County, OR. 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.