I recommend planting the tubers in potting soil in small pots or even an open Ziploc bag hung along an indoor line (so there is not much soil to warm up). Do not overwater at this stage they only need slightly moist potting soil. They need a bit of warmth and indirect light. Place the pots in a well-lit room in your home or greenhouse. You can pinch back to the second leaf set for a fuller flowering plant as the foliage emerges. The foliage will regrow if broken or pinched. 

Then when the danger of all frost has passed in your region, move the young plants or tubers outside for planting in a daily sunny location. Plant each tuber individually 4  - 6” deep in the soil, 12 - 18 inches apart or in very large pots (minimum 5 gallon size). If you have some organic fertilizer, glacier rock dust and/or bone meal (max 1 tablespoon/ hole mixed into the soil under the tuber), it is good to incorporate when planting. I have read not to add high nitrogen fertilizer after July as it can affect the tuber viability in storage in the winter.

There are a number of pests that can cause trouble in the dahlia garden. But the dahlias most destructive enemy in it’s early stages of growth and development outside is the slug. Once you move your tubers are planted outside, focus on eliminating or discouraging slugs from eating the foliage. Nighttime flashlight and bucket slug hunts, egg shells, beer traps and slug bait are all options in dahlia preservation.

If well cared for your dahlias should bloom from July until frost. I have grown all these varieties here in Chilliwack with great success. Dahlia’s enjoy full sun, and warm soil. They require lots of water during flowering in summer.  Most dahlias also require staking and will do best in a non-windy location. Once the outdoor soil temperature has warmed up in June, I mulch around mine with straw to retain moisture in the soil during the hotter part of summer months for water conservation. 

Enjoy!