Weeds must be controlled as the seedlings do not compete well. When plants reach about the thickness of a pencil, mulch may be applied to control weeds and conserve moisture. Harvest onions when the green leafy tops weaken at soil level and fall over.
Sow seed indoors in late winter. Sprinkle on soil surface, barely covering, and keep moist until the thread-like seedlings emerge. Grow in full sun, and cool conditions, with afternoon temps under 75 degrees Fahrenheit.
Try to ensure a gap of at least 5.94 inches (15.24 cm) when sowing to prevent overcrowding your seedlings.By our calculations, you should look at sowing Bronze d'amposta about 28 days before your last frost date.
Set seedlings outdoors 6-8 week before last frost of spring into rich, finely-worked garden soil. Plant in rows one foot apart and allow up to 6 inches between seedlings in the row.
By our calculations, you should look at planting out Bronze d'amposta about 42 days before your last frost date.
Named for the small city of Amposta, Spain.