Choose a sunny location with at least 6 to 8 hours of direct sunlight
Plant in well-draining, fertile soil
Prepare the soil with compost or aged manure
Plant dahlia tubers after the danger of frost has passed
Place tubers 4 to 6 inches deep with the eye facing up
Space plants 12 to 36 inches apart, depending on variety
Water lightly after planting, then keep soil evenly moist
Avoid overwatering to prevent tuber rot
Add stakes or supports for taller varieties at planting time
Pinch back the growing tips when plants are about 12 inches tall
Deadhead spent flowers regularly to encourage more blooms
Fertilize with a low-nitrogen fertilizer during the growing season
Mulch around plants to retain moisture and suppress weeds
Watch for pests such as slugs, aphids, and earwigs
Dig up tubers after the first frost in colder climates
Allow tubers to dry before storing
Store tubers in a cool, dark, frost-free place over winter
Divide tubers in spring if needed before replanting