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When to Plant Rue in Kenai Peninsula Borough, AK

Kenai Peninsula Borough, Alaska Zone 5a May

Top priorities for Kenai Peninsula Borough, Alaska gardeners in May

May is a pivotal month for Kenai Peninsula Borough, Alaska gardens. Focus on these tasks first and you'll set up the rest of the season for success.

Avg. last frost May 17
Avg. first frost September 25
Soil temp (4") 52°F
Watering High
Pest pressure Low
Daylight 16.8 hrs
  1. Time to transplant rue

    Harden off for 7 days — a little more sun each day — before planting. That's the difference between a seedling that thrives and one that stalls.

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Rue is a bitter, aromatic perennial herb with bluish-green foliage used historically in medicine and as a pest deterrent. Handle with care as its sap can cause skin irritation.

Kenai Peninsula Borough, Alaska is in USDA Zone 5a. The average last spring frost is May 17 and the first fall frost is September 25, giving you a growing season of approximately 131 days.

At an elevation of 1,824 feet, Kenai Peninsula Borough receives approximately 55.7 inches of rainfall annually with predominantly silt loam soil. Summer highs average 60°F, so choose short-season varieties of Rue to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Rue root diseases.

Kenai Peninsula Borough, AK (Zone 5a) Short season
131 days
Last Spring Frost May 17
131 growing days
First Fall Frost September 25

Kenai Peninsula Borough Soil Profile

Soil Type

Silt Loam

Soil pH

5.2-6.8

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✗ May not fit
Transplant: May 19 🍅 Harvest: Jul 28 – Sep 29
Recommended (50%) ✗ May not fit
Transplant: May 24 🍅 Harvest: Aug 2 – Oct 4
Safe Start (90%) ✗ May not fit
Transplant: Jun 8 🍅 Harvest: Aug 17 – Oct 19

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 Kenai Peninsula Borough

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

Soil pH

Your soil pH (5.2–6.8) overlaps with Rue's range (6.0–7.5), though not a perfect match.

Soil Texture

The silt loam soil in Kenai Peninsula Borough is excellent for Rue — good drainage, moisture retention, and nutrient holding capacity.

Organic Matter

Organic matter is excellent (6.6%) — Rue will thrive.

How to Plant Rue

0.5"
Planting Depth
8"
Between Plants
12"
Between Rows

Succession Planting Rue

2
successive plantings in your 131-day season

Sow every 8 weeks. Last sowing by Jun 27 to harvest before frost.

Plant Water Budget

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

Monthly Watering Guide for Rue

Rue needs approximately 0.5 inches of water per week (2.2" per month). Here's how your county's rainfall compares month by month.

Month Rue Needs Rainfall You Supplement Action
Jan 3.2" 0" ❄️ Dormant
Feb 2.4" 0" ❄️ Dormant
Mar 2" 0" ❄️ Dormant
Apr 1.5" 0" ❄️ Dormant
May 2.2" 2.3" 0" ✅ Rainfall sufficient
Jun 2.2" 3.8" 0" ✅ Rainfall sufficient
Jul 2.2" 7.6" 0" ✅ Rainfall sufficient
Aug 2.2" 8.3" 0" ✅ Rainfall sufficient
Sep 2.2" 10.1" 0" ✅ Rainfall sufficient
Oct 7" 0" ❄️ Dormant
Nov 4.3" 0" ❄️ Dormant
Dec 3.2" 0" ❄️ Dormant

Water needs are for active growing months only (May–Sep in Kenai Peninsula Borough). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.

Rue 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.

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

Rue Planting Timeline — Kenai Peninsula Borough, AK

Rue Planting Calendar

Activity When Date Range
Transplant Outdoors May 24 May 24 – Jun 7
Harvest August 2 Aug 2 – Oct 4

Plant 0.5" deep · 8" apart · Rows 12" apart

Month-by-Month Timeline

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

Growing Conditions

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

70–90 days

🧪 Soil pH

Needs 6–7.5 · Your soil: acceptable

🗺️ USDA Zone

Zone 5a

📆 Growing Season

131 days in Kenai Peninsula Borough

Growing Tips for Rue in Kenai Peninsula Borough

Direct sow Rue outdoors after May 17 in Kenai Peninsula Borough when soil has warmed and frost danger has passed.

General growing tips

Start seeds indoors or direct sow. Plant in well-drained soil. Wear gloves when handling as sap can cause phytophotodermatitis. Prune in early spring.

Companion Planting

Good Companions

Avoid Planting Near

  • Basil
  • Sage

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Rue in Kenai Peninsula Borough, AK?

Kenai Peninsula Borough is in Zone 5a with an average last frost of May 17. Plan your Rue planting based on this frost date — see the calendar above for exact timing.

What planting zone is Kenai Peninsula Borough, AK?

Kenai Peninsula Borough, Alaska is in USDA Hardiness Zone 5a. The average last spring frost is May 17 and first fall frost is September 25.

🌱

Your Kenai Peninsula Borough Garden Planner — Free

A 24-page printable planner built for Kenai Peninsula Borough (Zone 5a). 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 Kenai Peninsula 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.