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When to Plant Spinach in Sitka City and Borough, AK

Spinach is a nutrient-packed cool-season green that grows quickly in spring and fall. It is rich in iron, vitamins, and antioxidants and excellent raw or cooked.

Sitka City and Borough, Alaska is in USDA Zone 7a. The average last spring frost is April 20 and the first fall frost is October 24, giving you a growing season of approximately 187 days.

At an elevation of 1,935 feet, Sitka City and Borough receives approximately 21.8 inches of rainfall annually with predominantly silt loam soil. Summer highs average 69ยฐF, so choose short-season varieties of Spinach to ensure they mature before fall.

Sitka City and Borough, AK (Zone 7a) Moderate season
187 days
Last Spring Frost April 20
187 growing days
First Fall Frost October 24

Sitka City and Borough Soil Profile

Soil Type

Silt Loam

Soil pH

4.9-6.4

Drainage

Well Drained

Plant Planting Risk Windows

Early Start (70% safe) ✓ Fits season (91 days to spare)
Start indoors: Mar 8 Transplant: Apr 12 🍅 Harvest: May 17 – Jul 19
Recommended (50%) ✓ Fits season (89 days to spare)
Start indoors: Mar 16 Transplant: Apr 20 🍅 Harvest: May 25 – Jul 27
Safe Start (90%) ✓ Fits season (83 days to spare)
Start indoors: Apr 8 Transplant: May 13 🍅 Harvest: Jun 17 – Aug 19

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.

Plant Water Budget

Plant needs
1.0″/week
Rainfall provides
0.5″/week
You supply
0.5″/week
Watering frequency 1-2 times/week
Season total 849 gal / 100 sq ft
Spinach needs ~74 GDD — county provides 327 GDD Excellent fit

Spinach Planting Timeline โ€” Sitka City and Borough, AK

Spinach Planting Calendar

Activity When Date Range
Start Indoors March 16 Mar 16 โ€“ Mar 30
Transplant Outdoors April 20 Apr 20 โ€“ May 4
Direct Sow April 6 Apr 6 โ€“ Apr 27
Fall Sowing August 15 Aug 15 โ€“ Aug 29
Harvest May 25 May 25 โ€“ Jul 27

Plant 0.5" deep ยท 6" apart ยท Rows 12" apart

Month-by-Month Timeline

MonthActivities
January โ€”
February โ€”
March Start Indoors
April Transplant Outdoors Direct Sow
May Transplant Outdoors Harvest
June Harvest
July Harvest
August Fall Sowing
September โ€”
October โ€”
November โ€”
December โ€”

Growing Conditions

Sun

Partial Shade (3-6 hours)

Water

Moderate โ€” regular watering

Days to Maturity

35โ€“50 days

Soil pH

6.5 โ€“ 7.5

USDA Zone

Zone 7a

Growing Season

187 days

Growing Tips for Sitka City and Borough

Direct sow as soon as soil can be worked in spring. Plant in partial shade for summer crops to delay bolting. Succession plant every 2 weeks for continuous harvest.

Companion Planting

Good Companions

Level Up Your Garden

๐ŸŒพ Save Your Own Spinach Seeds
Life Cycle Annual
Pollination Wind Pollinated
How to Collect Let plants bolt. Harvest seed stalks when seeds turn tan.
Storage Store airtight; viable 5 years at 35ยฐF, under 45% humidity.

Wind pollinated โ€” isolate 1/2 mile for purity. Easy to let bolt in heat.

Frequently Asked Questions

When should I plant Spinach in Sitka City and Borough, AK?

Sitka City and Borough is in Zone 7a with an average last frost of April 20. Plan your Spinach planting based on this frost date โ€” see the calendar above for exact timing.

What planting zone is Sitka City and Borough, AK?

Sitka City and Borough, Alaska is in USDA Hardiness Zone 7a. The average last spring frost is April 20 and first fall frost is October 24.

๐ŸŒฑ

Plan Your Garden with Confidence

Get our free Garden Planner โ€” designed to help Sitka City and Borough gardeners in Zone 7a 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.

Data sources: USDA Plant Hardiness Zone Map (2023), NOAA 30-Year Climate Normals. Frost dates are based on 50% probability averages for Sitka City and Borough, AK. Local conditions may vary. Last updated: April 2026.