Onions

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

Plant name Zone Start seeds indoors Start seeds outdoors Plant seedlings/transplants outdoors Plant spacing # plants per person
Onions 3a March 1-15 Not recommended April 15-May 1 6 inches 12-20
Onions 3b March 1-15 Not recommended April 15-May 1 6 inches 12-20
Onions 4a March 1-15 Not recommended April 15-May 1 6 inches 12-20
Onions 4b March 1-15 Not recommended April 15-May 1 6 inches 12-20
Onions 5a Feb. 1-15 Not recommended March 15-April 1 6 inches 12-20
Onions 5b Feb. 1-15 Not recommended March 15-April 1 6 inches 12-20
Onions 6a Feb. 1-15 Not recommended March 15-April 1 6 inches 12-20
Onions 6b Feb. 1-15 Not recommended March 15-April 1 6 inches 12-20
Onions 7a Feb. 1-15 Not recommended March 15-April 1 6 inches 12-20
Onions 7b Feb. 1-15 Not recommended March 15-April 1 6 inches 12-20
Onions 8a Jan. 1-15 Not recommended Feb. 15-March 1 6 inches 12-20
Onions 8b Jan. 1-15 Not recommended Feb. 15-March 1 6 inches 12-20
Onions 9a Dec. 1-15 Not recommended Jan. 15-30 6 inches 12-20
Onions 9b Dec. 1-15 Not recommended Jan. 15-30 6 inches 12-20
Onions 10a Jan. 15-30; Aug. 1-15 Not recommended March 1-April 15; Oct. 15-Nov. 30 6 inches 12-20
Onions 10b Jan. 15-30; Aug. 1-15 Not recommended March 1-April 15; Oct. 15-Nov. 30 6 inches 12-20
Onions 11a Jan. 15-30; Aug. 1-15 Not recommended March 1-April 15; Oct. 15-Nov. 30 6 inches 12-20
Onions 11b Jan. 15-30; Aug. 1-15 Not recommended March 1-April 15; Oct. 15-Nov. 30 6 inches 12-20

* The best way to plant onions is as sets, or seedlings with small bulbs.