Planting Guides

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

Anchorage, Alaska

USDA Zone 4b

Last Frost: May 20

Last updated: October 30, 2025

Plant kale in Anchorage May 1-15 for summer harvest or July 15-25 for frost-sweetened fall crop in Alaska's unique Zone 4b growing conditions.

TTom Erikson

October 30, 2025

Kale plants growing in Anchorage garden with Alaska mountain backdrop showing Zone 4b conditions — — Image © PlantReference.org 2026

Quick Answer

Plant kale in Anchorage May 1-15 for summer harvest or July 15-25 for fall crop. Alaska's cool temperatures and 20-hour summer daylight create ideal conditions for sweet, tender kale.

TL;DR

Plant kale in Anchorage May 1-15 for summer harvest or July 15-25 for fall crop. Anchorage's Zone 4b climate with 118-day growing season and cool temperatures creates ideal conditions for sweet, tender kale. Brassica oleracea 'Winterbor' and Brassica oleracea 'Red Russian' are top choices for Alaska's short but productive growing window.

Frequently Asked Questions

When should I start kale seeds indoors in Anchorage?

Start kale seeds indoors March 15-30 for spring transplanting, about 6-8 weeks before your planned outdoor planting date of May 1-15. Use a cool location (60-65°F/15-18°C) as kale prefers cooler conditions for germination than many vegetables. Anchorage's naturally cool spring temperatures are actually ideal for hardening off seedlings—just protect them from freezing winds during the transition period.

Can kale survive winter in Anchorage?

Kale cannot survive Anchorage winters outdoors without significant protection due to Zone 4b temperatures regularly dropping below 0°F (-18°C). However, you can extend the harvest season into November using cold frames, row covers, or unheated greenhouses. Brassica oleracea 'Winterbor' offers the best cold tolerance for season extension attempts, surviving down to 10°F (-12°C) with protection.

Why is my spring-planted kale turning yellow in Anchorage?

Yellow leaves on spring kale in Anchorage typically indicate waterlogged soil rather than heat stress (unlikely in Alaska's cool climate). Anchorage's wet springs can saturate soils, preventing proper root function and nutrient uptake. Improve drainage with raised beds or organic matter additions, and avoid overwatering. Cool, wet soil conditions also slow nitrogen uptake, so side-dress with fish emulsion every 3 weeks during active growth.

Which kale variety grows fastest in Alaska's short season?

Brassica oleracea 'Red Russian' is the fastest-maturing variety for Anchorage, ready to harvest in just 50-60 days. This makes it ideal for succession plantings throughout Alaska's short growing season. Its flat, tender leaves are perfect for salads and smoothies, while the purple-veined foliage adds visual interest to Alaska gardens. Plant every 3-4 weeks from May through July for continuous harvest.

How do I know when kale is ready to harvest in Anchorage?

Harvest kale leaves when they reach 6-8 inches long, typically 6-8 weeks after planting in Anchorage conditions. Alaska's cool temperatures keep leaves tender much longer than warmer climates, so you can safely harvest leaves up to 12-14 inches without toughness issues. For fall crops, wait until after the first frost for maximum sweetness—this natural "candy kale" effect only occurs in cool climates like Anchorage.

What's the best way to preserve my Anchorage kale harvest?

Freeze or dehydrate kale for long-term storage. For freezing, blanch leaves 2-3 minutes, cool in ice water, drain thoroughly, and package in freezer bags for winter use. For dehydration, Alaska's dry indoor winter air makes homemade kale chips simple and effective. Store fresh, unharvested kale in the garden under row covers into November for continuous fresh harvests until hard freezes arrive.

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Tagged with

#when to plant kale anchorage #alaska kale growing #zone 4b kale #anchorage gardening #alaska vegetables #short season kale #cold hardy kale varieties #anchorage frost dates #alaska gardening tips #northern climate vegetables

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.