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When to Plant Rutabaga in Gresham, OR

Multnomah County, Oregon Zone 9a July

This month in Multnomah County, Oregon

Here's what deserves your attention in Multnomah County, Oregon this month. Everything below is tailored to Zone 9a and timed around your local frost dates.

Avg. last frost April 14
Avg. first frost October 27
Soil temp (4") 89°F
Watering Critical
Pest pressure High
Daylight 15.2 hrs
  1. Bring in the rutabaga

    This is the payoff month. Bring a basket, bring a friend, and get into the beds.

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Rutabagas are a cross between turnips and cabbage, producing large yellow-fleshed roots with a sweet, mild flavor. They are excellent mashed, roasted, or in stews.

Gresham, Oregon is in USDA Zone 9a. The average last spring frost is April 14 and the first fall frost is October 27, giving you a growing season of approximately 196 days.

At an elevation of 357 feet, Multnomah County receives approximately 35.9 inches of rainfall annually with predominantly silt loam soil. Summer highs average 84°F, so choose short-season varieties of Rutabaga to ensure they mature before fall.

Gresham, OR (Zone 9a) Moderate season
196 days
Last Spring Frost April 14
196 growing days
First Fall Frost October 27

Gresham Soil Profile

Soil Type

Silt Loam

Soil pH

5.8-6.3

Drainage

Well Drained

Rutabaga Planting Risk Windows

Early Start (70% safe) ✓ Fits season (74 days to spare)
Transplant: Apr 8 🍅 Harvest: Jul 1 – Aug 5
Recommended (50%) ✓ Fits season (77 days to spare)
Transplant: Apr 14 🍅 Harvest: Jul 7 – Aug 11
Safe Start (90%) ✓ Fits season (75 days to spare)
Transplant: May 9 🍅 Harvest: Aug 1 – Sep 5

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 Gresham

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

Soil pH

Your soil pH (5.8–6.3) overlaps with Rutabaga's range (6.0–7.5), though not a perfect match.

Soil Texture

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

Drainage

Drainage is adequate for Rutabaga.

Organic Matter

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

How to Plant Rutabaga

1"
Planting Depth
15"
Between Plants
24"
Between Rows

Fall planting: Sow 8 weeks before your first frost date for a fall harvest.

Succession Planting Rutabaga

2
successive plantings in your 196-day season

Sow every 9.1 weeks. Last sowing by Jul 19 to harvest before frost.

For a dedicated fall crop, sow by Sep 01.

Rutabaga Water Budget

Plant needs
0.7″/week
Rainfall provides
0.8″/week
You supply
0.1″/week
Watering frequency Only during dry spells
Season total 245 gal / 100 sq ft

Monthly Watering Guide for Rutabaga

Rutabaga needs approximately 0.7 inches of water per week (3" per month). Here's how your county's rainfall compares month by month.

Month Rutabaga Needs Rainfall You Supplement Action
Jan 5.8" 0" ❄️ Dormant
Feb 4.1" 0" ❄️ Dormant
Mar 3.5" 0" ❄️ Dormant
Apr 3" 2.3" 0.7" 💧 Light watering
May 3" 2.3" 0.7" 💧 Light watering
Jun 3" 1.3" 1.7" 🚿 Regular watering
Jul 3" 0.6" 2.4" 🚿 Regular watering
Aug 3" 0.7" 2.3" 🚿 Regular watering
Sep 3" 1.6" 1.4" 💧 Light watering
Oct 3" 2.9" 0.1" 💧 Light watering
Nov 6" 0" ❄️ Dormant
Dec 4.9" 0" ❄️ Dormant

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

Rutabaga 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.

Rutabaga needs ~1,170 GDD — county provides 2,548 GDD Excellent fit

Rutabaga Planting Timeline — Gresham, OR

Rutabaga Planting Calendar

Activity When Date Range
Direct Sow March 24 Mar 24 – Apr 14
Harvest June 16 Jun 16 – Jul 21
Fall Sowing September 1 Sep 1 – Sep 15

Plant 1" deep · 15" apart · Rows 24" apart

Month-by-Month Timeline

MonthActivities
January
February
March Direct Sow
April Direct Sow
May
June Harvest
July Harvest
August
September Fall Sowing
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.7"/week · Only during dry spells

📅 Days to Maturity

80–100 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 9a

📆 Growing Season

196 days in Multnomah County

Growing Tips for Rutabaga in Gresham

Direct sow Rutabaga outdoors after April 14 in Multnomah County when soil has warmed and frost danger has passed.

Common pests for Rutabaga in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.

General growing tips

Direct sow in early summer for fall harvest. Thin seedlings to 6-8 inches apart. Flavor improves significantly after a few light frosts.

Companion Planting

Good Companions

Avoid Planting Near

  • Potatoes

Check more plant combinations with our Companion Planting Checker →

🌱

Your Multnomah County Garden Planner — Free

A 22-page printable planner built for Multnomah 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 Multnomah County, OR. Local conditions may vary. Last updated: July 2026.