When to Plant Dahlia in Alaska

Growing Dahlia in Alaska: Complete Guide

Dahlia (Dahlia pinnata) is a warm-season crop that needs a head start indoors before Alaska's last frost. Most Alaska gardeners begin seeds indoors around Sunday, March 29, 2026 and move transplants outside around Sunday, May 17, 2026, after the risk of frost has passed.

Because Alaska stretches across 16 USDA hardiness zones (1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, 6a, 6b, 7a, 7b, 8a, 8b), planting windows can shift by as much as six to eight weeks from one end of the state to the other. Gardeners in the warmer southern zones can start earlier, while those in cooler northern zones should wait until the zone table above shows their last frost has passed.

With 90 days to maturity, Dahlia needs the indoor head start that Alaska's growing season requires. Starting indoors ensures you have strong transplants ready the moment outdoor conditions are right.

Dahlia requires full sun (6-8 hours) and regular (1-2 inches/week) moisture. Alaska's long summer days accelerate growth, but frost can arrive early in August — season extension with row covers is essential.

For the most precise planting dates tailored to your exact location, enter your ZIP code on our planting calendar or use the zone table above to find the schedule for your area of Alaska.