How do you keep onions from bolting?
To help keep your onions from bolting, we suggest protecting your onions from environmental stresses. Make sure you keep your onions adequately watered during the hot summer months and protected from any early season cold spells. Hot dry weather in summer or a cold snap early in the season can force mature onions to begin to set flower much earlier than plants not under stress. If your onions start to bolt, be sure to cut the flowers back as soon as possible.