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When to Plant Rhubarb in Haines Borough, AK

Haines Borough, Alaska Zone 5b May

May to-do list for Haines Borough, Alaska

Your garden in Haines Borough, Alaska is working on a schedule, even when you're not. Here's where you should be this May.

Avg. last frost May 7
Avg. first frost September 29
Soil temp (4") 58°F
Watering High
Pest pressure Low
Daylight 16.6 hrs
  1. Transplant rhubarb outside

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

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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.

Haines Borough, Alaska is in USDA Zone 5b. The average last spring frost is May 7 and the first fall frost is September 29, giving you a growing season of approximately 145 days.

At an elevation of 1,921 feet, Haines Borough receives approximately 57.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 68°F, so choose short-season varieties of Rhubarb to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rhubarb root diseases.

Haines Borough, AK (Zone 5b) Short season
145 days
Last Spring Frost May 7
145 growing days
First Fall Frost September 29

Haines Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season
Transplant: May 19
Recommended (50%) ✓ Fits season
Transplant: May 28
Safe Start (90%) ✓ Fits season
Transplant: Jun 18

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 Haines Borough

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

Soil pH

Your soil pH (4.9–6.4) is more acidic than Rhubarb prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in Haines 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 (6.6%) — 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
1.7″/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 2.8" 0" ❄️ Dormant
Feb 2.6" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 2" 0" ❄️ Dormant
May 4.3" 2.7" 1.6" 💧 Light watering
Jun 4.3" 4" 0.3" 💧 Light watering
Jul 4.3" 8.1" 0" ✅ Rainfall sufficient
Aug 4.3" 8.5" 0" ✅ Rainfall sufficient
Sep 4.3" 10.6" 0" ✅ Rainfall sufficient
Oct 6.5" 0" ❄️ Dormant
Nov 4.1" 0" ❄️ Dormant
Dec 3.4" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Haines 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 ~548 GDD — county provides 145 GDD May not mature

Rhubarb Planting Timeline — Haines Borough, AK

Rhubarb Planting Calendar

Activity When Date Range
Transplant Outdoors May 28 May 28 – Jun 11

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

Month-by-Month Timeline

MonthActivities
January
February
March
April
May Transplant Outdoors
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

145 days in Haines Borough

Growing Tips for Rhubarb in Haines Borough

Direct sow Rhubarb outdoors after May 07 in Haines Borough when soil has warmed and frost danger has passed.

Your 145.0-day growing season in Haines 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 Haines Borough, AK?

Haines Borough is in Zone 5b with an average last frost of May 7. Plan your Rhubarb planting based on this frost date — see the calendar above for exact timing.

What planting zone is Haines Borough, AK?

Haines Borough, Alaska is in USDA Hardiness Zone 5b. The average last spring frost is May 7 and first fall frost is September 29.

🌱

Your Haines Borough Garden Planner — Free

A 24-page printable planner built for Haines Borough (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 Haines Borough, AK. Local conditions may vary. Last updated: May 2026.

Sources & credits

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