Dahlia

Dahlias need fertile, well-drained soil with a pH of 6.0-7.0. Add compost before planting and avoid excess nitrogen, then install supports early for tall, heavy-flowered cultivars.

Sun

Full sun

Water

1–2 in/week once growing

Spacing

18 in

First harvest

90–120 from tuber

Tips

• Plant tubers about 4-6 inches deep with the growing eye upward, spacing compact types 18 inches apart and larger types farther apart.
• Water sparingly before shoots appear, then supply about 1-2 inches weekly once plants are growing.
• Apply a low-nitrogen flower fertilizer after growth begins, using the labeled rate.
• Protect emerging shoots from slugs and inspect tender growth for aphids.
• Cut flowers and deadhead regularly, and lift tubers after frost where winters would freeze them.