Dahlias should be planted about 4 to 6 inches (10 to 15 cm) deep in the soil. The tuber is typically placed on its side with the growing eye facing up, then covered with soil to that depth. This depth allows the tuber to be well- covered but not too deep, which helps prevent rot and encourages healthy sprouting

. Spacing between plants should be at least 12 to 18 inches (30 to 45 cm) to allow for good air circulation and growth

. For larger varieties, spacing up to 18 to 30 inches (45 to 75 cm) is recommended

. In raised beds, a soil depth of at least 18 inches (45 cm) is advised to accommodate tubers and root growth adequately

. In summary:

• Plant tubers 4-6 inches deep.
• Place tuber on its side with the eye facing up.
• Space plants 12-18 inches apart (or more for larger varieties).
• Raised beds should be at least 18 inches deep for dahlias.

This planting depth and spacing ensure healthy growth and blooming of dahlias.