Visual Guide to Floral Hemp Maturation

Knowing how far along floral hemp is in its flower development can be tricky. Catching the transition between vegetative and reproductive growth in the field is difficult. Often when we notice the crop flowering it has actually been in the reproductive phase for a couple of weeks. Those who grow floral hemp in controlled environments where daylength can be manually changed know exactly when the reproductive phase starts. Field producers do not have this luxury.

Understanding where the crop is in terms of floral development is critical for properly timed harvest. Initially, harvest recommendations were based on trichome and stigma ("hairs") coloration. This method is rather vague and can lead to potentially hot crops. Increasingly, seed companies and breeders recommend harvesting based off of weeks after floral initiation. Because cannabinoid production and accumulation is so tightly regulated by the plant's genetics, basing harvest on weeks after floral initiation is a more objective means of harvesting. Additionally, basing harvest on weeks after flower initiation makes scheduling compliance testing easy. For example, if a crop is to be harvested 6 weeks (42 days) after flower initiation then compliance testing should be done 12 days after flower initiation (this assumes the USDA final rule compliance testing of 30 days before harvest). When in doubt, submitting samples to a lab for cannabinoid analysis is the best means to definitively know how far along your crop is in cannabinoid production.

To help visualize floral development, we grew 'BaOx' and 'Cherry Wine' in the greenhouse under 16 hours of light and then reduced this to 12 hours to switch to reproductive growth. These images are from randomly selected plants from the same cultivar throughout a 10-week period.