When to Plant Radish in Kenai Peninsula Borough, AK
May in Kenai Peninsula Borough, Alaska — your action list
A quick May briefing for Kenai Peninsula Borough, Alaska gardeners — what's urgent, what's next, and what can wait.
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Direct-sow radish
Your soil is 52°F — warm enough for these to germinate without babying.
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Start harvesting radish
The more you pick, the more the plant produces. Letting fruit overripen tells the plant it's time to stop.
Get ahead of June
- First harvests: radish
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.
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 Radish to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Radish root diseases.
Kenai Peninsula Borough Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.8
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 Kenai Peninsula Borough
How your county's soil matches Radish's growing requirements.
Soil pH
Your soil pH (5.2–6.8) overlaps with Radish's range (6.0–7.0), though not a perfect match.
Soil Texture
The silt loam soil in Kenai Peninsula Borough is excellent for Radish — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (6.6%) — 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 Aug 21 to harvest before frost.
For a dedicated fall crop, sow by Jul 17.
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 | — | 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.
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 — Kenai Peninsula Borough, AK
Radish Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Direct Sow | May 3 | May 3 – May 24 |
| Harvest | May 31 | May 31 – Jun 21 |
| Fall Sowing | July 17 | Jul 17 – Jul 31 |
Plant 0.5" deep · 2" apart · Rows 6" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | — |
| May | Direct Sow Harvest |
| June | Harvest |
| July | Fall Sowing |
| August | — |
| 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: acceptable
🗺️ USDA Zone
Zone 5a
📆 Growing Season
131 days in Kenai Peninsula Borough
Growing Tips for Radish in Kenai Peninsula Borough
Direct sow Radish outdoors after May 17 in Kenai Peninsula Borough when soil has warmed and frost danger has passed.
Your generous 131.0-day season in Kenai Peninsula 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 56" of annual rainfall in Kenai Peninsula 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 Kenai Peninsula Borough, AK?
Kenai Peninsula Borough is in Zone 5a with an average last frost of May 17. Plan your Radish 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.