When to Plant Brussels Sprouts in Kenai Peninsula Borough, AK
Your May game plan for Kenai Peninsula Borough, Alaska
If you only do a handful of things in the garden this May, make it these. They're sequenced around your zone's frost timing.
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Plant out brussels sprouts
Pick a cloudy afternoon or evening to plant. Less transplant shock, and your seedlings will barely blink.
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Scatter brussels sprouts into prepared beds
Mark the row. Birds and stray feet both have opinions about unmarked beds.
A few tasks this May that'll pay off in June
- Starting indoors: brussels sprouts
Brussels sprouts are a cold-hardy brassica that produces miniature cabbage-like heads along a tall stalk. Flavor improves after a light frost.
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 Brussels Sprouts to ensure they mature before fall. Ample rainfall means less supplemental watering, but ensure good drainage to prevent Brussels Sprouts 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 Brussels Sprouts's growing requirements.
Soil pH
Your soil pH (5.2–6.8) overlaps with Brussels Sprouts's range (6.0–7.5), though not a perfect match.
Soil Texture
The silt loam soil in Kenai Peninsula Borough is excellent for Brussels Sprouts — good drainage, moisture retention, and nutrient holding capacity.
Organic Matter
Organic matter is excellent (6.6%) — Brussels Sprouts will thrive.
How to Plant Brussels Sprouts
Fall planting: Sow 10 weeks before your first frost date for a fall harvest.
Plant Water Budget
Monthly Watering Guide for Brussels Sprouts
Brussels Sprouts needs approximately 0.9 inches of water per week (3.9" per month). Here's how your county's rainfall compares month by month.
| Month | Brussels Sprouts 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 | 3.9" | 2.3" | 1.6" | 💧 Light watering |
| Jun | 3.9" | 3.8" | 0.1" | 💧 Light watering |
| Jul | 3.9" | 7.6" | 0" | ✅ Rainfall sufficient |
| Aug | 3.9" | 8.3" | 0" | ✅ Rainfall sufficient |
| Sep | 3.9" | 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.
Brussels Sprouts 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.
Brussels Sprouts Planting Timeline — Kenai Peninsula Borough, AK
Brussels Sprouts Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 12 | Apr 12 – Apr 26 |
| Transplant Outdoors | May 17 | May 17 – May 31 |
| Direct Sow | May 3 | May 3 – May 24 |
| Harvest | August 16 | Aug 16 – Oct 11 |
| Fall Sowing | July 17 | Jul 17 – Jul 31 |
Plant 1" deep · 15" apart · Rows 24" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Transplant Outdoors Direct Sow |
| June | — |
| July | Fall Sowing |
| August | Harvest |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
0.9"/week · Natural rainfall sufficient
📅 Days to Maturity
90–130 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 Brussels Sprouts in Kenai Peninsula Borough
Direct sow Brussels Sprouts outdoors after May 17 in Kenai Peninsula Borough when soil has warmed and frost danger has passed.
Your 131.0-day growing season in Kenai Peninsula Borough is tight for Brussels Sprouts (90.0-130.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Brussels Sprouts in this region include cabbage worm and flea beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 12-14 weeks before first fall frost. Stake tall plants to prevent toppling. Remove lower leaves as sprouts develop to improve air circulation.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Brussels Sprouts in Other Locations
Frequently Asked Questions
When should I plant Brussels Sprouts in Kenai Peninsula Borough, AK?
Kenai Peninsula Borough is in Zone 5a with an average last frost of May 17. Plan your Brussels Sprouts 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.