When do the seed pods grow? After the flower petals have dropped off, the plant uses all its remaining energy to reproduce. The seed pods will grow fat with seeds and eventually the seed vents will open to reseed themselves. Brianna Perry2023-03-20T22:30:30+00:00March 17, 2023|Planting and Growing, Poppy Seed General Information| Share This Story, Choose Your Platform! FacebookXRedditLinkedInWhatsAppTumblrPinterestEmail