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When to Plant Radish in North Slope Borough, AK

North Slope Borough, Alaska Zone 2b May

May in the garden — North Slope Borough, Alaska

Each item below is timed to North Slope Borough, Alaska's frost dates and soil temperatures. Skip nothing, stress about nothing.

Soil temp (4") 42°F
Watering Critical
Pest pressure Low
Daylight 20.6 hrs

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Radishes are one of the fastest-growing vegetables, with some varieties ready in under a month. They come in round, elongated, and large winter types.

North Slope Borough, Alaska is in USDA Zone 2b. The average last spring frost is May 27 and the first fall frost is July 31, giving you a growing season of approximately 65 days.

At an elevation of 2,600 feet, North Slope Borough receives approximately 16.6 inches of rainfall annually with predominantly silt loam soil. Summer highs average 69°F, so choose short-season varieties of Radish to ensure they mature before fall. With low rainfall, drip irrigation is essential for growing Radish successfully. Mulch heavily to conserve soil moisture.

North Slope Borough, AK (Zone 2b) Very short season
65 days
Last Spring Frost May 27
65 growing days
First Fall Frost July 31
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North Slope Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.7

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (134 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3
Recommended (50%) ✓ Fits season (134 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3
Safe Start (90%) ✓ Fits season (134 days to spare)
Transplant: Apr 15 🍅 Harvest: May 13 – Jun 3

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 North Slope Borough

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

Soil pH

Your soil pH (4.9–6.7) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.

Soil Texture

The silt loam soil in North Slope Borough is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.

Drainage

Drainage is adequate for Radish.

Organic Matter

Organic matter is excellent (5.7%) — Radish will thrive.

How to Plant Radish

0.5"
Planting Depth
2"
Between Plants
6"
Between Rows

Fall planting: Sow 12 weeks before your first frost date for a fall harvest.

Plant Water Budget

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

Monthly Watering Guide for Radish

Radish 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 Radish Needs Rainfall You Supplement Action
Jan 0.7" 0" ❄️ Dormant
Feb 0.6" 0" ❄️ Dormant
Mar 0.6" 0" ❄️ Dormant
Apr 0.5" 0" ❄️ Dormant
May 2.2" 0.7" 1.5" 🚿 Regular watering
Jun 2.2" 1.2" 1" 💧 Light watering
Jul 2.2" 2.2" 0" ✅ Rainfall sufficient
Aug 2.4" 0" ❄️ Dormant
Sep 3.1" 0" ❄️ Dormant
Oct 2.2" 0" ❄️ Dormant
Nov 1.3" 0" ❄️ Dormant
Dec 1" 0" ❄️ Dormant

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

Radish 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.

Radish needs ~50 GDD — county provides 113 GDD Excellent fit

Radish Planting Timeline — North Slope Borough, AK

Radish Planting Calendar

Activity When Date Range
Direct Sow May 20 May 20 – Jun 10
Harvest June 17 Jun 17 – Jul 8
Fall Sowing May 8 May 8 – May 22

Plant 0.5" deep · 2" apart · Rows 6" apart

Month-by-Month Timeline

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

☀️ Sun

Full Sun (6-8+ hours)

💧 Water

0.5"/week · Natural rainfall sufficient

📅 Days to Maturity

22–35 days

🧪 Soil pH

Needs 6–7 · Your soil: too_acidic

🗺️ USDA Zone

Zone 2b

📆 Growing Season

65 days in North Slope Borough

Growing Tips for Radish in North Slope Borough

Common pests for Radish 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 every 1-2 weeks for continuous harvest. Do not transplant. Harvest spring radishes promptly to prevent them from becoming pithy and hot.

Companion Planting

Good Companions

Avoid Planting Near

  • Hyssop

Check more plant combinations with our Companion Planting Checker →

Frequently Asked Questions

When should I plant Radish in North Slope Borough, AK?

North Slope Borough is in Zone 2b with an average last frost of May 27. Plan your Radish planting based on this frost date — see the calendar above for exact timing.

What planting zone is North Slope Borough, AK?

North Slope Borough, Alaska is in USDA Hardiness Zone 2b. The average last spring frost is May 27 and first fall frost is July 31.

🌱

Your North Slope Borough Garden Planner — Free

A 24-page printable planner built for North Slope Borough (Zone 2b). 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 North Slope 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.