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When to Plant Hardy Kiwi in Marion County, OR

Marion County, Oregon Zone 8b May

Your May game plan for Marion County, Oregon

May is a pivotal month for Marion County, Oregon 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 30
Soil temp (4") 70°F
Watering Moderate
Pest pressure High
Daylight 14.6 hrs
  1. Get hardy kiwi in the ground

    Your last frost (April 20) has passed. These warm-season crops can handle outdoor soil now.

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Hardy kiwi produces grape-sized, smooth-skinned fruits eaten whole without peeling. Unlike fuzzy kiwi, it is extremely cold-hardy to -25F once established.

Marion County, Oregon is in USDA Zone 8b. The average last spring frost is April 20 and the first fall frost is October 30, giving you a growing season of approximately 193 days.

At an elevation of 422 feet, Marion County receives approximately 50.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 88°F, providing good warmth for Hardy Kiwi during the growing season. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Hardy Kiwi root diseases.

Marion County, OR (Zone 8b) Moderate season
193 days
Last Spring Frost April 20
193 growing days
First Fall Frost October 30

Marion County Soil Profile

Soil Type

Silt Loam

Soil pH

5.4-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 4
Recommended (50%) ✓ Fits season
Transplant: May 11
Safe Start (90%) ✓ Fits season
Transplant: May 30

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 Marion County

How your county's soil matches Hardy Kiwi's growing requirements.

Soil pH

Your soil pH (5.4–6.8) overlaps with Hardy Kiwi's range (5.5–7.0), though not a perfect match.

Soil Texture

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

Organic Matter

Organic matter is excellent (4.5%) — Hardy Kiwi will thrive.

How to Plant Hardy Kiwi

72"
Between Plants
96"
Between Rows

Plant Water Budget

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

Monthly Watering Guide for Hardy Kiwi

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

Month Hardy Kiwi Needs Rainfall You Supplement Action
Jan 6.9" 0" ❄️ Dormant
Feb 5.1" 0" ❄️ Dormant
Mar 4.9" 0" ❄️ Dormant
Apr 4.3" 3.8" 0.5" 💧 Light watering
May 4.3" 2.8" 1.5" 💧 Light watering
Jun 4.3" 2" 2.3" 🚿 Regular watering
Jul 4.3" 0.8" 3.5" 🚿 Regular watering
Aug 4.3" 1" 3.3" 🚿 Regular watering
Sep 4.3" 1.9" 2.4" 🚿 Regular watering
Oct 4.3" 4.2" 0.1" 💧 Light watering
Nov 8.2" 0" ❄️ Dormant
Dec 9" 0" ❄️ Dormant

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

Hardy Kiwi 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.

Hardy Kiwi needs ~23,360 GDD — county provides 3,088 GDD May not mature

Hardy Kiwi Planting Timeline — Marion County, OR

Hardy Kiwi Planting Calendar

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

· 72" apart · Rows 96" 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

1"/week · Natural rainfall sufficient

📅 Days to Maturity

1095–1825 days

🧪 Soil pH

Needs 5.5–7 · Your soil: acceptable

🗺️ USDA Zone

Zone 8b

📆 Growing Season

193 days in Marion County

Growing Tips for Hardy Kiwi in Marion County

Direct sow Hardy Kiwi outdoors after April 20 in Marion County when soil has warmed and frost danger has passed.

Your 193.0-day growing season in Marion County is tight for Hardy Kiwi (1095.0-1825.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant male and female vines for pollination. Provide very strong trellising as vines become massive. Prune similarly to grapes. Protect young plants from late spring frost.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Hardy Kiwi in Marion County, OR?

Marion County is in Zone 8b with an average last frost of April 20. Plan your Hardy Kiwi planting based on this frost date — see the calendar above for exact timing.

What planting zone is Marion County, OR?

Marion County, Oregon is in USDA Hardiness Zone 8b. The average last spring frost is April 20 and first fall frost is October 30.

🌱

Your Marion County Garden Planner — Free

A 24-page printable planner built for Marion 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 Marion 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.