Planting dahlias early inside in mn
Thank you for the question. Dahlia tubers can be planted directly outside in the ground in late May. They grow quickly provided they receive plenty of water and direct sunlight. If you want to get earlier blooms, you can follow this advice from University of Iowa Extension:
When should I start dahlias indoors?
For earlier bloom, plant dahlia tubers indoors in early April. Fill an 8-inch-diameter pot about one-half full with a commercial potting mix, place a tuber horizontally on the potting mix surface, then cover with an additional 1 to 2 inches of potting soil. Water thoroughly. When growth emerges, place the dahlias in a sunny window or under artificial lighting.
Plant dahlias outdoors after the danger of frost is past. Before planting, harden or acclimate the dahlias to outdoor conditions for several days.
To learn more, read our publication "Growing Dahlias": https://www.extension.umn.edu/garden/yard-garden/flowers/growing-dahlias/
Thank you for contacting Extension.