Dahlia

Use our zone-based planting guide to know when to plant dahlia.

Plant name Zone Start seeds indoors (spring/fall) Start seeds outdoors (spring/fall) Plant seedlings/transplants outdoors (spring/fall) Plant spacing # plants per person
Dahlia 3a March 15-April 1 On/around May 30 (2 weeks after last frost) On/around May 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 3b March 15-April 1 On/around May 30 (2 weeks after last frost) On/around May 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 4a March 15-April 1 On/around May 30 (2 weeks after last frost) On/around May 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 4b March 15-April 1 On/around May 30 (2 weeks after last frost) On/around May 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 5a Feb. 15-March 1 On/around April 30 (2 weeks after last frost) On/around April 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 5b Feb. 15-March 1 On/around April 30 (2 weeks after last frost) On/around April 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 6a Feb. 15-March 1 On/around April 30 (2 weeks after last frost) On/around April 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 6b Feb. 15-March 1 On/around April 30 (2 weeks after last frost) On/around April 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 7a Feb. 15-March 1 On/around April 30 (2 weeks after last frost) On/around April 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 7b Feb. 15-March 1 On/around April 30 (2 weeks after last frost) On/around April 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 8a Jan. 15-Feb. 1 On/around March 30 (2 weeks after last frost) On/around March 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 8b Jan. 15-Feb. 1 On/around March 30 (2 weeks after last frost) On/around March 30 (2 weeks after last frost) 9 inches-3 feet (depending on variety) n/a
Dahlia 9a 6-8 weeks before planting outdoors Nov. 1-May 30 Nov. 1-May 30 9 inches-3 feet (depending on variety) n/a
Dahlia 9b 6-8 weeks before planting outdoors Nov. 1-May 30 Nov. 1-May 30 9 inches-3 feet (depending on variety) n/a
Dahlia 10a 6-8 weeks before planting outdoors Nov. 1-May 30 Nov. 1-May 30 9 inches-3 feet (depending on variety) n/a
Dahlia 10b 6-8 weeks before planting outdoors Nov. 1-May 30 Nov. 1-May 30 9 inches-3 feet (depending on variety) n/a
Dahlia 11a 6-8 weeks before planting outdoors Nov. 1-May 30 Nov. 1-May 30 9 inches-3 feet (depending on variety) n/a
Dahlia 11b 6-8 weeks before planting outdoors Nov. 1-May 30 Nov. 1-May 30 9 inches-3 feet (depending on variety) n/a

* Dahlias grow as tubers and come in a wide variety of colors and sizes. Tubers can be grown as perennials in Zone 8 and higher; otherwise, grow them as annuals or dig up tubers and store for the winter.