Angel Trumpet seed pods, either Brugmansia or Datura, are ready for harvest once they reach maturity, usually after 3 to 4 months of growth. An Angel Trumpet seed pod is mature when the outer husk starts to soften, the pod starts to yellow and the stem turns brown.
Ripened seeds are dark brown to black in color, while immature seeds are white or lighter in color. Seeds harvested too early may not be viable. Depending on the variety grown, some plants produce sterile seeds, especially certain hybrid varieties. For best results, harvest Angel Trumpet seed pods once they reach full maturity.