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When to Plant Rhubarb in Valdez-Cordova, AK

Valdez-Cordova, Alaska Zone 5b May

May in the garden — Valdez-Cordova, Alaska

Welcome to May in Zone 5b. These are the moves that will have the biggest impact on your growing season.

Avg. last frost May 12
Avg. first frost October 5
Soil temp (4") 47°F
Watering High
Pest pressure Low
Daylight 17.1 hrs
June will be here before you know it — start on
  • Transplants going out: rhubarb

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Rhubarb is a long-lived perennial vegetable grown for its tart, colorful stalks. Only the stalks are edible as the leaves contain toxic oxalic acid.

Valdez-Cordova, Alaska is in USDA Zone 5b. The average last spring frost is May 12 and the first fall frost is October 5, giving you a growing season of approximately 146 days.

At an elevation of 2,888 feet, Valdez-Cordova receives approximately 38.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 66°F, so choose short-season varieties of Rhubarb to ensure they mature before fall.

Valdez-Cordova, AK (Zone 5b) Short season
146 days
Last Spring Frost May 12
146 growing days
First Fall Frost October 5

Valdez-Cordova Soil Profile

Soil Type

Silt Loam

Soil pH

5-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 21
Recommended (50%) ✓ Fits season
Transplant: Jun 2
Safe Start (90%) ✓ Fits season
Transplant: Jun 25

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 Valdez-Cordova

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

Soil pH

Your soil pH (5.0–6.8) is more acidic than Rhubarb prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Valdez-Cordova is excellent for Rhubarb — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Rhubarb.

Organic Matter

Organic matter is excellent (6.2%) — Rhubarb will thrive.

How to Plant Rhubarb

1"
Planting Depth
30"
Between Plants
42"
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 Rhubarb

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

Month Rhubarb Needs Rainfall You Supplement Action
Jan 1.9" 0" ❄️ Dormant
Feb 1.8" 0" ❄️ Dormant
Mar 1.5" 0" ❄️ Dormant
Apr 1.2" 0" ❄️ Dormant
May 4.3" 1.5" 2.8" 🚿 Regular watering
Jun 4.3" 2.9" 1.4" 💧 Light watering
Jul 4.3" 5.3" 0" ✅ Rainfall sufficient
Aug 4.3" 5.5" 0" ✅ Rainfall sufficient
Sep 4.3" 6" 0" ✅ Rainfall sufficient
Oct 4.3" 5.3" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2.4" 0" ❄️ Dormant

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

Rhubarb 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.

Rhubarb needs ~0 GDD — county provides 0 GDD May not mature

Rhubarb Planting Timeline — Valdez-Cordova, AK

Rhubarb Planting Calendar

Activity When Date Range
Transplant Outdoors June 2 Jun 2 – Jun 16

Plant 1" deep · 30" apart · Rows 42" apart

Month-by-Month Timeline

MonthActivities
January
February
March
April
May
June Transplant Outdoors
July
August
September
October
November
December

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

1"/week · Natural rainfall sufficient

📅 Days to Maturity

365–730 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 5b

📆 Growing Season

146 days in Valdez-Cordova

Growing Tips for Rhubarb in Valdez-Cordova

Direct sow Rhubarb outdoors after May 12 in Valdez-Cordova when soil has warmed and frost danger has passed.

Your 146.0-day growing season in Valdez-Cordova is tight for Rhubarb (365.0-730.0 days to maturity). Start indoors and choose early-maturing varieties.

General growing tips

Plant crowns in early spring in rich, well-drained soil. Do not harvest stalks the first year. Pull (do not cut) stalks at harvest to avoid introducing rot.

Companion Planting

Good Companions

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rhubarb in Valdez-Cordova, AK?

Valdez-Cordova is in Zone 5b with an average last frost of May 12. Plan your Rhubarb planting based on this frost date — see the calendar above for exact timing.

What planting zone is Valdez-Cordova, AK?

Valdez-Cordova, Alaska is in USDA Hardiness Zone 5b. The average last spring frost is May 12 and first fall frost is October 5.

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Your Valdez-Cordova Garden Planner — Free

A 24-page printable planner built for Valdez-Cordova (Zone 5b). 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 Valdez-Cordova, AK. 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.