Pre-flower

Pre-flowers are the earliest visible indicator of cannabis plant sex, allowing growers to identify and remove males before they pollinate females and ruin the crop. They appear at the internodes (where branches meet the main stem) starting around week 4-6 of vegetative growth in photoperiod plants — before the plant has been triggered into full flowering. Female pre-flowers are tiny calyx structures, typically light green and teardrop-shaped, with two white hair-like pistils emerging from the tip. These pistils are the stigmas that catch pollen during fertilization. Male pre-flowers are spherical pollen sacs that hang from short stalks at the internodes, resembling tiny green grapes; they begin appearing 1-2 weeks earlier than female pre-flowers. Identifying sex during pre-flower is critical when growing regular (non-feminized) seeds — males must be removed before they open and release pollen, which can occur within 7-10 days of first appearance. With feminized seeds, pre-flower inspection serves as a hermaphrodite check: 99%+ of feminized seeds produce female pre-flowers, but the rare hermaphrodite can show both pistils and pollen sacs at the same nodes (often called "bananas" or "nanners"). Pre-flowers are easiest to spot with a 10x jeweler's loupe or smartphone macro lens, focusing on internodes near the upper third of the plant where mature growth occurs first. Once the plant is flipped to 12/12, pre-flowers expand into the full flower clusters of the flowering stage.