Northwest Arctic Borough, AK — Planting Guide
Northwest Arctic Borough is in USDA Zone 1b. The average last spring frost is May 18 and the first fall frost is August 6, giving you a growing season of approximately 80 days.
At an elevation of 2,144 ft, Northwest Arctic Borough receives approximately 42.6 in of rainfall annually. Summer highs average 56°F with winter lows around -10°F. The predominant soil type is Silt Loam.
🌡️ Zone
1b (-55°F to -50°F min)
❄️ Last Frost
May 18
🍂 First Frost
August 6
📅 Growing Season
80 days
⛰️ Elevation
2,144 ft
🌧️ Annual Rainfall
42.6 in
Monthly Watering Calendar
When you'll need to water your garden — based on average monthly rainfall vs. the ~1 inch/week most gardens need.
View detailed monthly data
| Month | Avg Rainfall | Rainy Days | Extra Water Needed | Watering Effort |
|---|---|---|---|---|
| Jan | 2.1 in | 6 days | — | None |
| Feb | 1.6 in | 5 days | — | None |
| Mar | 1.7 in | 5 days | — | None |
| Apr | 1.4 in | 5 days | — | None |
| May | 2 in | 6 days | 2.3 in | High |
| Jun | 2.9 in | 8 days | 1.4 in | Moderate |
| Jul | 6 in | 12 days | — | Low |
| Aug | 6.1 in | 14 days | — | Low |
| Sep | 8.6 in | 15 days | — | Low |
| Oct | 4.7 in | 10 days | — | None |
| Nov | 3.1 in | 8 days | — | None |
| Dec | 2.5 in | 7 days | — | None |
Annual total: 42.7 in. Gardens typically need ~1 inch of water per week during the growing season. Months marked "None" for extra water are outside the active growing season for your zone — most gardens are dormant and don't need irrigation during those months.
Northwest Arctic Borough Soil Profile
Soil Type
Silt Loam
Soil pH
5-6.7
Drainage
Well Drained
Gardening Difficulty Score
Northwest Arctic Borough is a very forgiving place to garden. Most plants thrive here with minimal effort.
Local Gardening Help in Northwest Arctic Borough
Free expert help is closer than you think. Your county's cooperative extension office connects you with trained gardeners, soil testing labs, and local programs — all specific to Northwest Arctic Borough's climate and soil.
County Extension Office
Northwest Arctic Borough University of Alaska Fairbanks Cooperative Extension Extension Office
Phone: 907-474-5211
Visit Extension Office Website →
Extension offices are run by land-grant universities and funded by the USDA. Their advice is free, research-based, and tailored to your county's specific conditions.
Master Gardener Program
Free gardening help from trained volunteers
Master Gardeners are community volunteers who complete 40–60 hours of university horticultural training. They answer gardening questions, diagnose plant problems, and offer workshops — all free.
Many extension offices run a Master Gardener hotline where you can call or email with photos of plant problems for free diagnosis.
Soil Testing
Available through your extension office
Before amending your soil, get it tested. Your extension office offers soil testing (typically $10–$25) that tells you exact pH, nutrient levels, and amendment recommendations specific to what you want to grow.
Services Available in Northwest Arctic Borough
Finding local nurseries & garden centers in Northwest Arctic Borough
Why Buy Local
Local nurseries carry plants that are proven to grow in your area. Staff can give you advice specific to Northwest Arctic Borough's soil and climate that big-box stores can't. Plants from local growers are typically hardier because they're already acclimated to your zone.
How to Find Them
Search for "nurseries near Northwest Arctic Borough AK" or "garden center Northwest Arctic Borough" on Google Maps. Also check with your extension office — they often maintain lists of reputable local nurseries and plant sales.
Community gardens & gardening groups
Community gardens are a great way to learn from experienced gardeners in your area, especially if you're limited on space. Search "community garden Northwest Arctic Borough AK" or check your extension office and local parks department. Facebook groups like "Northwest Arctic Borough Gardeners" or "Alaska Gardening" are also excellent for local advice and plant swaps.
Sunlight & Day Length
Monthly daylight hours and peak sun — critical for onion varieties, photoperiod-sensitive plants, and solar garden planning.
Longest Day
24 hours
Summer solstice daylight
Shortest Day
0 hours
Winter solstice daylight
Peak Sun Hours
11.8 hr/day peak (summer)
Peak sun hours (green dashed line below) account for cloud cover — this is the usable direct sunlight your garden actually receives. Most vegetables need 6+ peak sun hours.
Onion tip: Your long summer days (14+ hours) support long-day onion varieties like Walla Walla, Sweet Spanish, and Ailsa Craig.
View detailed monthly data
| Month | Daylight Hours | Peak Sun Hours | Day Length |
|---|---|---|---|
| January | 3.3 hr | 1 hr | Short day |
| February | 7.5 hr | 2.7 hr | Short day |
| March | 11.1 hr | 4.5 hr | Short day |
| April | 15 hr | 7 hr | Long day |
| May | 19 hr | 8.7 hr | Long day |
| June | 24 hr | 11.8 hr | Long day |
| July | 20.9 hr | 10.5 hr | Long day |
| August | 16.7 hr | 7.5 hr | Long day |
| September | 12.7 hr | 5.2 hr | Neutral |
| October | 8.9 hr | 3.2 hr | Short day |
| November | 4.8 hr | 1.3 hr | Short day |
| December | 0 hr | 0 hr | Short day |
Peak sun hours factor in typical cloud cover — use these for solar panel and shade-planning calculations.
Soil Temperature & Composting Calendar
Monthly soil temps tell you when to plant warm-season crops, and when your compost pile is actively working.
Plant Warm Crops When
Soil reaches 60°F+
Soil warm enough from Jul through Aug.
Best Month to Compost
Jun
Microbial activity peaks when soil is warm.
Active Composting
4 months
Short season — insulate pile or use indoor vermicomposting.
View detailed monthly data
| Month | Soil 4" Deep | Soil 8" Deep | Compost Activity | Time to Finish |
|---|---|---|---|---|
| Jan | 0°F | 11°F | ❄️ Dormant | ~36 weeks |
| Feb | -0°F | 10°F | ❄️ Dormant | ~36 weeks |
| Mar | 13°F | 16°F | ❄️ Dormant | ~36 weeks |
| Apr | 29°F | 27°F | ❄️ Dormant | ~36 weeks |
| May | 44°F | 40°F | 🐢 Slow | ~24 weeks |
| Jun | 53°F | 49°F | ♻️ Active | ~14 weeks |
| Jul | 63°F | 56°F | ♻️ Active | ~14 weeks |
| Aug | 61°F | 59°F | ♻️ Active | ~14 weeks |
| Sep | 56°F | 53°F | ♻️ Active | ~14 weeks |
| Oct | 38°F | 42°F | ❄️ Dormant | ~36 weeks |
| Nov | 24°F | 31°F | ❄️ Dormant | ~36 weeks |
| Dec | 8°F | 19°F | ❄️ Dormant | ~36 weeks |
Highlighted rows = soil 60°F+ (safe for warm-season transplants). Compost finishes fastest during peak activity months.
Pest & Disease Pressure in Northwest Arctic Borough
Computed from local climate patterns — warmer, humid conditions increase pest generations and fungal disease risk.
Insect Pest Pressure
Low — basic prevention and occasional hand-picking.
Disease Risk
Moderate — watch for mildew and blight during wet periods.
Seasonal Risk
View 4 common pests in your area
| Pest | Risk Level | Peak Months |
|---|---|---|
| Aphids | Low | Jun, Jul, Aug |
| Cabbage worms | Moderate | Jun, Jul, Aug |
| Flea beetles | Low | May, Jun, Jul |
| Slugs | Moderate | May, Jun, Jul, Aug |
Organic pest management tips
- Use row covers on susceptible crops during peak pest months
- Apply neem oil preventatively every 7-14 days during active pest season
- Interplant with strong-scented herbs (basil, marigold) to confuse pests
- Hand-pick larger pests (beetles, caterpillars) in early morning when they're sluggish
- Practice crop rotation — never plant the same family in the same spot within 3 years
Wind & Microclimate
Wind dries soil, stresses plants, and affects frost patterns. Understanding your exposure helps with garden placement.
Seasonal Wind Speed
Spring: 11 mph Summer: 9 mph
Fall: 9 mph Winter: 13 mph
Prevailing wind: N. Moderate wind — consider a temporary windbreak for young seedlings.
Windbreak Benefit
5.1/10
Moderately beneficial — a simple fence or trellis can protect delicate crops from wind stress.
Frost Pocket Risk
High
Hilly terrain with 1,001 ft of elevation range — cold air pools in low spots. Avoid planting frost-sensitive crops in valleys.
Rainwater Harvesting Potential
How much water you can collect, when to collect it, and what size system you need for your garden.
Annual Collection
21,281 gal
Per 1,000 sq ft of roof area (at 80% collection efficiency)
Recommended Setup
6 rain barrels (55 gal each)
For a typical 500 sq ft garden. Serious collectors: consider a 1,500 gal tank.
Legal Status
Unrestricted
Rainwater harvesting is fully legal in your state with no restrictions.
Best Collection Months
Jul, Aug, Sep, Oct
Highest rainfall months — your barrels will fill up quickly during these months.
Months to Draw From Storage
Feb, Mar, Apr
Dry months when you'll rely on stored water — size your storage for this gap.
Rainwater collection tips for your area
- Your county receives approximately 42.7 inches of rain per year
- A 1,000 sq ft roof can collect roughly 21,281 gallons annually
- Rainwater harvesting is fully legal in your state
- Stock up on stored water before your dry season (Feb, Mar, Apr)
- Use a first-flush diverter to keep roof debris out of your collection
Soil & Growing Conditions in Northwest Arctic Borough
Soil Type
Silt Loam
Soil pH 5–6.7 · Somewhat Poorly Drained drainage
Raised beds strongly recommended here — native soil drainage or texture limits in-ground options.
Watering Needs
Drought stress: 1.5/10
Northwest Arctic Borough has very low drought pressure. Natural rainfall usually meets garden needs — water only during extended dry spells.
Season Tips
80-day frost-free season
A short season means indoor starts are critical for warm-season crops. Prioritise cold-hardy, fast-maturing varieties and use row covers to extend autumn harvests.
Free Garden Planner
Plan your entire garden season — organize planting dates, track what you're growing, and know exactly when to start seeds, transplant, and harvest.
Recommended for Your Garden
Test your soil pH, nitrogen, phosphorus, and potassium levels before planting.
Get instant, accurate soil pH readings to fine-tune your amendments.
Boost soil fertility and structure with rich, well-aged organic compost.
🥬 Vegetables to Grow in Northwest Arctic Borough
3 vegetables that grow well in Zone 1b with planting dates for Northwest Arctic Borough.
Show all 3 vegetables with planting dates
| Plant | Start Indoors | Direct Sow | Transplant | Harvest | Days to Maturity |
|---|---|---|---|---|---|
| Cabbage | Apr 6 | May 11 | May 18 | Jul 20 – Sep 14 | 60–100 |
| Microgreens | Apr 6 | May 11 | May 18 | May 25 – Jun 22 | 7–21 |
| Savoy Cabbage | Apr 6 | May 11 | May 18 | Jul 27 – Sep 21 | 70–110 |
Monthly Planting Guide for Northwest Arctic Borough
Gardening Guides & Resources
Helpful guides from The Ultimate Homestead to improve your garden in Northwest Arctic Borough.
Frequently Asked Questions
What planting zone is Northwest Arctic Borough, AK?
Northwest Arctic Borough is in USDA Hardiness Zone 1b. This zone classification determines which perennial plants survive winter and sets the baseline for frost timing across the county.
When is the last frost in Northwest Arctic Borough, AK?
Based on 30 years of NOAA weather station data, the median last spring frost in Northwest Arctic Borough falls around May 18. Plan transplants and direct-sow dates relative to this date.
When is the first fall frost in Northwest Arctic Borough, AK?
The median first fall frost in Northwest Arctic Borough arrives around August 6. Harvest or protect frost-sensitive crops — tomatoes, peppers, basil, squash — before this date.
What is the soil like in Northwest Arctic Borough for gardening?
Northwest Arctic Borough has predominantly Silt Loam soil with a pH range of 5–6.7 and Somewhat Poorly Drained drainage. The native soil conditions make raised beds a particularly good investment here — they let you control drainage and fertility independent of the ground soil.
What is grown commercially in Northwest Arctic Borough?
Northwest Arctic Borough has commercial agriculture that includes Hay, Cattle, Potatoes. These crops reflect the local climate and soil conditions — what succeeds commercially often translates well to home gardens in the same area.
Is Northwest Arctic Borough a good location for home gardening?
Northwest Arctic Borough scores 89/100 (Excellent) on our Microclimate Index, which combines frost reliability, drought pressure, soil challenge, elevation risk, and long-term climate trend. This is an above-average location for home gardening with relatively predictable growing conditions.
Plan Your Garden with Confidence
Get our free Garden Planner — designed to help Northwest Arctic Borough gardeners in Zone 1b organize planting dates, track what's growing, and never miss a planting window.
Get Your Free Garden Planner →Free download. Plan your entire garden season in minutes.
