When to Plant Radish in Ketchikan Gateway Borough, AK
Your May planting checklist for Ketchikan Gateway Borough, Alaska
Welcome to May in Zone 7b. These are the moves that will have the biggest impact on your growing season.
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Bring in the radish
This is the payoff month. Bring a basket, bring a friend, and get into the beds.
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.
Ketchikan Gateway Borough, Alaska is in USDA Zone 7b. The average last spring frost is April 25 and the first fall frost is October 19, giving you a growing season of approximately 177 days.
At an elevation of 1,212 feet, Ketchikan Gateway Borough receives approximately 57.5 inches of rainfall annually with predominantly silt loam soil. Summer highs average 65°F, so choose short-season varieties of Radish to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.
Ketchikan Gateway Borough Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.7
Drainage
Well Drained
Plant Planting Risk Windows
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 Ketchikan Gateway Borough
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (5.0–6.7) is more acidic than Radish prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Ketchikan Gateway 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 (5.9%) — Radish will thrive.
How to Plant Radish
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Succession Planting Radish
Sow every 2.4 weeks. Last sowing by Sep 14 to harvest before frost.
For a dedicated fall crop, sow by Aug 10.
Plant Water Budget
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 | — | 2.8" | 0" | ❄️ Dormant |
| Feb | — | 2.6" | 0" | ❄️ Dormant |
| Mar | — | 1.8" | 0" | ❄️ Dormant |
| Apr | 2.2" | 2" | 0.2" | 💧 Light watering |
| May | 2.2" | 2.4" | 0" | ✅ Rainfall sufficient |
| Jun | 2.2" | 4.5" | 0" | ✅ Rainfall sufficient |
| Jul | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| Aug | 2.2" | 9.5" | 0" | ✅ Rainfall sufficient |
| Sep | 2.2" | 11" | 0" | ✅ Rainfall sufficient |
| Oct | 2.2" | 6.6" | 0" | ✅ Rainfall sufficient |
| Nov | — | 3.8" | 0" | ❄️ Dormant |
| Dec | — | 3.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (Apr–Oct in Ketchikan Gateway 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 Planting Timeline — Ketchikan Gateway Borough, AK
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | April 11 | Apr 11 – May 2 |
| Harvest | May 9 | May 9 – May 30 |
| Fall Sowing | August 10 | Aug 10 – Aug 24 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Direct Sow |
| May | Direct Sow Harvest |
| June | — |
| July | — |
| August | Fall Sowing |
| September | — |
| October | — |
| November | — |
| December | — |
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 7b
📆 Growing Season
177 days in Ketchikan Gateway Borough
Growing Tips for Radish in Ketchikan Gateway Borough
Direct sow Radish outdoors after April 25 in Ketchikan Gateway Borough when soil has warmed and frost danger has passed.
Your generous 177.0-day season in Ketchikan Gateway Borough allows multiple plantings of Radish. Sow every 11.0 days for continuous harvest.
Common pests for Radish in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
With 58" of annual rainfall in Ketchikan Gateway Borough, ensure good drainage for Radish — excess moisture can promote root rot and fungal diseases.
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
Check more plant combinations with our Companion Planting Checker →
Radish in Other Locations
Frequently Asked Questions
When should I plant Radish in Ketchikan Gateway Borough, AK?
Ketchikan Gateway Borough is in Zone 7b with an average last frost of April 25. Plan your Radish planting based on this frost date — see the calendar above for exact timing.
What planting zone is Ketchikan Gateway Borough, AK?
Ketchikan Gateway Borough, Alaska is in USDA Hardiness Zone 7b. The average last spring frost is April 25 and first fall frost is October 19.
Your Ketchikan Gateway Borough Garden Planner — Free
A 24-page printable planner built for Ketchikan Gateway 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.