When to Plant Butternut Squash in Fairbanks North Star Borough, AK
May to-do list for Fairbanks North Star Borough, Alaska
We've pulled the most time-sensitive tasks for Fairbanks North Star Borough, Alaska this May and put them front and centre. Tackle them in order.
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Plant butternut squash from seed, right in the garden
Your soil is 42°F — warm enough for these to germinate without babying.
To set up a strong June, finish these tasks
- Transplants going out: butternut squash
- Starting indoors: butternut squash
Butternut squash is a popular winter squash with a long neck, small seed cavity, and sweet, nutty orange flesh. It stores exceptionally well for months.
Fairbanks North Star Borough, Alaska is in USDA Zone 3b. The average last spring frost is May 15 and the first fall frost is September 8, giving you a growing season of approximately 116 days.
At an elevation of 2,540 feet, Fairbanks North Star Borough receives approximately 29.3 inches of rainfall annually with predominantly silt loam soil. Summer highs average 69°F, so choose short-season varieties of Butternut Squash to ensure they mature before fall.
Fairbanks North Star Borough Soil Profile
Soil Type
Silt Loam
Soil pH
5.2-6.4
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 Fairbanks North Star Borough
How your county's soil matches Butternut Squash's growing requirements.
Soil pH
Your soil pH (5.2–6.4) is more acidic than Butternut Squash prefers (6.0–7.0). Add garden lime to raise pH.
Soil Texture
The silt loam soil in Fairbanks North Star Borough is excellent for Butternut Squash — good drainage, moisture retention, and nutrient holding capacity.
Drainage
Drainage is adequate for Butternut Squash.
Organic Matter
Organic matter is excellent (6.7%) — Butternut Squash will thrive.
How to Plant Butternut Squash
Plant Water Budget
Monthly Watering Guide for Butternut Squash
Butternut Squash needs approximately 1.1 inches of water per week (4.8" per month). Here's how your county's rainfall compares month by month.
| Month | Butternut Squash Needs | Rainfall | You Supplement | Action |
|---|---|---|---|---|
| Jan | — | 1.6" | 0" | ❄️ Dormant |
| Feb | — | 1.4" | 0" | ❄️ Dormant |
| Mar | — | 1" | 0" | ❄️ Dormant |
| Apr | — | 1" | 0" | ❄️ Dormant |
| May | 4.8" | 1.2" | 3.6" | 🚿 Regular watering |
| Jun | 4.8" | 2.4" | 2.4" | 🚿 Regular watering |
| Jul | 4.8" | 3.3" | 1.5" | 💧 Light watering |
| Aug | 4.8" | 4.1" | 0.7" | 💧 Light watering |
| Sep | 4.8" | 5.3" | 0" | ✅ Rainfall sufficient |
| Oct | — | 3.8" | 0" | ❄️ Dormant |
| Nov | — | 2.2" | 0" | ❄️ Dormant |
| Dec | — | 1.9" | 0" | ❄️ Dormant |
Water needs are for active growing months only (May–Sep in Fairbanks North Star Borough). Supplement amounts are based on average rainfall — actual needs vary with temperature, soil, and mulching.
Butternut Squash 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.
Butternut Squash Planting Timeline — Fairbanks North Star Borough, AK
Butternut Squash Planting Calendar
| Activity | When | Date Range |
|---|---|---|
| Start Indoors | April 3 | Apr 3 – Apr 17 |
| Transplant Outdoors | June 5 | Jun 5 – Jun 19 |
| Direct Sow | May 29 | May 29 – Jun 19 |
| Harvest | September 4 | Sep 4 – Oct 9 |
Plant 1" deep · 30" apart · Rows 42" apart
Month-by-Month Timeline
| Month | Activities |
|---|---|
| January | — |
| February | — |
| March | — |
| April | Start Indoors |
| May | Direct Sow |
| June | Transplant Outdoors Direct Sow |
| July | — |
| August | — |
| September | Harvest |
| October | Harvest |
| November | — |
| December | — |
Growing Conditions
☀️ Sun
Full Sun (6-8+ hours)
💧 Water
1.1"/week · Natural rainfall sufficient
📅 Days to Maturity
85–110 days
🧪 Soil pH
Needs 6–7 · Your soil: too_acidic
🗺️ USDA Zone
Zone 3b
📆 Growing Season
116 days in Fairbanks North Star Borough
Growing Tips for Butternut Squash in Fairbanks North Star Borough
Direct sow Butternut Squash outdoors after May 15 in Fairbanks North Star Borough when soil has warmed and frost danger has passed.
Your 116.0-day growing season in Fairbanks North Star Borough is tight for Butternut Squash (85.0-110.0 days to maturity). Start indoors and choose early-maturing varieties.
Common pests for Butternut Squash in this region include squash vine borer and cucumber beetles. Use row covers early in the season and inspect plants weekly.
General growing tips
Start seeds indoors 3 weeks early or direct sow after frost. Allow 6-8 feet for sprawling vines. Harvest when the skin is hard and uniformly tan. Cure in the sun for 10 days.
Companion Planting
Good Companions
Avoid Planting Near
Check more plant combinations with our Companion Planting Checker →
Butternut Squash in Other Locations
Frequently Asked Questions
When should I plant Butternut Squash in Fairbanks North Star Borough, AK?
Fairbanks North Star Borough is in Zone 3b with an average last frost of May 15. Plan your Butternut Squash planting based on this frost date — see the calendar above for exact timing.
What planting zone is Fairbanks North Star Borough, AK?
Fairbanks North Star Borough, Alaska is in USDA Hardiness Zone 3b. The average last spring frost is May 15 and first fall frost is September 8.
Your Fairbanks North Star Borough Garden Planner — Free
A 24-page printable planner built for Fairbanks North Star Borough (Zone 3b). Planting dates, a month-by-month schedule, harvest log, seed inventory, and succession charts — all dialed in for your exact growing season.