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When to Plant Rhubarb in Wrangell City and Borough, AK

Wrangell City and Borough, Alaska Zone 7b May

Your May game plan for Wrangell City and Borough, Alaska

Here's what deserves your attention in Wrangell City and Borough, Alaska this month. Everything below is tailored to Zone 7b and timed around your local frost dates.

Avg. last frost April 23
Avg. first frost October 20
Soil temp (4") 62°F
Watering High
Pest pressure Moderate
Daylight 16.1 hrs
  1. Move rhubarb into the garden

    Your last frost (April 23) has passed. These warm-season crops can handle outdoor soil now.

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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.

Wrangell City and Borough, Alaska is in USDA Zone 7b. The average last spring frost is April 23 and the first fall frost is October 20, giving you a growing season of approximately 180 days.

At an elevation of 1,533 feet, Wrangell City and Borough receives approximately 35.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 59°F, so choose short-season varieties of Rhubarb to ensure they mature before fall.

Wrangell City and Borough, AK (Zone 7b) Moderate season
180 days
Last Spring Frost April 23
180 growing days
First Fall Frost October 20
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Wrangell City and Borough Soil Profile

Soil Type

Silt Loam

Soil pH

5.1-6.5

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 7
Recommended (50%) ✓ Fits season
Transplant: May 14
Safe Start (90%) ✓ Fits season
Transplant: Jun 2

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 Wrangell City and Borough

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

Soil pH

Your soil pH (5.1–6.5) is more acidic than Rhubarb prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Wrangell City and Borough is excellent for Rhubarb — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Rhubarb.

Organic Matter

Organic matter is excellent (6.1%) — 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
0.8″/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 1.6" 0" ❄️ Dormant
Mar 1.1" 0" ❄️ Dormant
Apr 4.3" 1.1" 3.2" 🚿 Regular watering
May 4.3" 1.4" 2.9" 🚿 Regular watering
Jun 4.3" 2.9" 1.4" 💧 Light watering
Jul 4.3" 4.4" 0" ✅ Rainfall sufficient
Aug 4.3" 6.2" 0" ✅ Rainfall sufficient
Sep 4.3" 5.4" 0" ✅ Rainfall sufficient
Oct 4.3" 4.8" 0" ✅ Rainfall sufficient
Nov 2.9" 0" ❄️ Dormant
Dec 2" 0" ❄️ Dormant

Water needs are for active growing months only (Apr–Oct in Wrangell City and Borough). 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 — Wrangell City and Borough, AK

Rhubarb Planting Calendar

Activity When Date Range
Transplant Outdoors May 14 May 14 – May 28

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
June
July
August
September
October
November
December
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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 7b

📆 Growing Season

180 days in Wrangell City and Borough

Growing Tips for Rhubarb in Wrangell City and Borough

Direct sow Rhubarb outdoors after April 23 in Wrangell City and Borough when soil has warmed and frost danger has passed.

Your 180.0-day growing season in Wrangell City and Borough 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 Wrangell City and Borough, AK?

Wrangell City and Borough is in Zone 7b with an average last frost of April 23. Plan your Rhubarb planting based on this frost date — see the calendar above for exact timing.

What planting zone is Wrangell City and Borough, AK?

Wrangell City and Borough, Alaska is in USDA Hardiness Zone 7b. The average last spring frost is April 23 and first fall frost is October 20.

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Your Wrangell City and Borough Garden Planner — Free

A 24-page printable planner built for Wrangell City and Borough (Zone 7b). 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 Wrangell City and Borough, 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.