Planting Guides

When to Plant Tomatoes in Anchorage: Complete Guide + Best Varieties for Zone 4b

Anchorage, Alaska

USDA Zone 4b

Last Frost: May 20

Last updated: November 30, 2025

Learn when to plant tomatoes in Anchorage with specific dates for Zone 4b. Compare 6 varieties, get a complete timeline, and discover which tomatoes grow best in Alaska.

TTom Erikson

November 30, 2025

Tomato seedlings growing in Anchorage greenhouse with Alaska mountain views showing Zone 4b growing conditions — — Image © PlantReference.org 2026

Quick Answer

Start tomato seeds indoors by April 7 in Anchorage. Transplant outdoors after May 26 when soil reaches 55°F. Choose early varieties like 'Stupice' (52-60 days) to beat the September 14 first frost.

TL;DR

Start tomato seeds indoors by April 7 in Anchorage's Zone 4b climate. Transplant outdoors after May 26 when nights stay above 45°F. Choose early varieties like 'Stupice' and 'Early Girl' that mature in 50-65 days to beat September 14 first frost. Alaska's 118-day growing season requires strategic variety selection and season extension techniques.

Frequently Asked Questions

Can I direct sow tomato seeds outdoors in Anchorage?

Direct sowing tomatoes in Anchorage is not recommended due to Zone 4b's cool soil temperatures and short growing season. Soil temperatures don't reach the required 60°F (16°C) consistently until mid-June, leaving insufficient time for seed germination, plant development, and fruit maturation before September frost.

Do I need a greenhouse to grow tomatoes in Anchorage?

A greenhouse isn't essential for tomato success in Anchorage, but it significantly improves results and extends the growing season. Many successful gardeners grow early varieties like Solanum lycopersicum 'Stupice' and {Solanum lycopersicum 'Early Girl' outdoors using row covers and other season extension techniques.

What's the latest I can plant tomatoes in Anchorage and still get a harvest?

The absolute latest transplant date for Anchorage tomato success is June 15, using only the earliest varieties like Solanum lycopersicum 'Stupice' (52-day maturity). This schedule allows harvest by August 6, providing 5-6 weeks before the average September 14 first frost.

Which tomato varieties handle Alaska's cool nights best?

Solanum lycopersicum 'Stupice' demonstrates the best cold tolerance, setting fruit reliably when nighttime temperatures drop to 40-45°F (4-7°C). This Czech heirloom was specifically bred for cold climate conditions similar to Alaska's.

How do I protect tomato plants from unexpected frost in Anchorage?

Keep frost protection materials readily available from late August onward, as Anchorage can experience frost 1-2 weeks before the September 14 average date. Row cover fabric provides 3-5°F (2-3°C) protection and can save plants from light frosts.

Can I save seeds from tomatoes grown in Anchorage for next year's planting?

Seed saving works well for open-pollinated varieties like Solanum lycopersicum 'Stupice', Solanum lycopersicum 'Cherokee Purple', Solanum lycopersicum 'Brandywine', and Solanum lycopersicum 'San Marzano'. Allow fruit to fully ripen on the plant, then extract and dry seeds using standard fermentation methods.

What soil amendments work best for tomatoes in Anchorage's volcanic soil?

Anchorage's volcanic soils drain well but often lack organic matter and tend toward acidity (pH 5.5-6.0). Add 3-4 inches (7.5-10 cm) of compost or well-aged manure annually to improve soil structure and provide slow-release nutrients.

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Tagged with

#Anchorage gardening #Alaska tomatoes #Zone 4b planting #short season varieties #tomato varieties Alaska #when to plant Anchorage #Alaska vegetable gardening #cold climate tomatoes #season extension techniques #Alaska growing guide

Written By

Tom Erikson

Tom is a lifelong Alaskan who gardens in Anchorage, where the growing season is short but intense. He works for the state cooperative extension service and has spent years figuring out what works in a climate where the ground freezes deep, the growing season starts in late May, and you get 19 hours of daylight in June. Tom grows cold-hardy vegetables, maintains a collection of boreal-adapted perennials, and experiments with season extension using cold frames and row covers. He writes about the realities of northern gardening—the unique advantages (those long summer days produce remarkable growth) and the genuine limitations. Tom's tone is calm and practical, with the quiet humor of someone who's gardened through Alaskan winters for decades.