How To Grow - Dahlias
Soil—not air—temperature is the key to healthy, beautiful dahlias. A soil temperature of around 60 degrees is ideal. They won't grow faster if planted in cool soil and it could actually retard growth. Dahlias thrive in generous sun exposure - 6 to 8 hours a day. (A little afternoon shade can be helpful for dahlias in very hot climates.) Plant tubers horizontally in holes that are 6 inches deep, and 12-18 inches apart, depending on how big the varietal you’re planting. Unless you live in a hot, extremely dry climate, no need to start watering until after your tubers have sprouted, which will be in 3 to 10 weeks. For more flowers and a bushier plant, pinch or cut the center shoot just above the third set of leaves when the plant is twelve to eighteen inches tall.