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Growing Green Gold: The Role of Cannabis Sex Testing in Crop Optimization

Updated: Mar 19

Cannabis sex testing involves identifying the sex of cannabis plants. It’s an important step in the cultivation process for several reasons:

  • At an early stage, growers can detect if any plants are male.

  • Female plants are the only plants that flower and produce the strong resinous buds for harvesting.

  • The testing saves time and money and can maximize a crop yield.

Cannabis Basics

Many experienced growers, often referred to as master gardeners, are familiar with the differences between male and female cannabis plants. Male plants are known for their preflower sacs, have fewer leaves and thicker stalks. They have X and Y chromosomes, do not produce cannabis resinous buds and have much less therapeutic value. In contrast, female plants have tear-drop shaped flowers, emit stronger aromas, and have more leaves. With two X chromosomes, they are prized for producing the highest concentration of cannabinoids, which are known for their psychoactive effects and therapeutic value. Master gardeners do not want the presence of any male plants in their growing rooms. It’s best to dispose of male plants as early as possible before they start signaling to mature female plants to make seeds and not flower.


However, sometimes in a growing room filled with female plants, one plant may become hermaphroditic (possessing both male and female traits) and start producing seeds. Hermaphroditism can occur due to several factors, and scientists don’t know why or what triggers this transformation. Growers do not want their female cannabis plants to become “hermies” because they trigger other female plants to produce seeds, and hermies produce less flower because they are putting energy towards seed production.


Hermies plants signal female plants to start producing seeds and not to flower.

Cannabis Sex qPCR DNA Testing

Master Gardeners buy their cannabis seeds from seed bank companies, who typically have a variety of strains to choose from and can guarantee that out of 100 seeds, only one seed will be a male plant. After two weeks of growing, essentially when the plants start showing leaves, cannabis sex testing can be used to detect male plants. By determining early on which plants are male, growers benefit by not spending time, resources and growing costs on male plants that ultimately will need to be destroyed.


Cannabis sex testing saves growers six weeks of growing costs.


There are two types of cannabis sex testing: DNA testing and chromosome analysis. DNA testing is the most accurate; it is a quantitative polymerase chain reaction (qPCR) genetic test that can detect specific  sequences of DNA over 95% of the time. The DNA is extracted from leaves and the thermocycler will detect which leaves have the presence of a Y chromosome, a male plant.


Choosing PB Laboratories (PBL) for Sex DNA Testing

Since Sex DNA testing only requires the use of leaves, growers are legally allowed to send them to any company in the U.S. However, there are benefits to using a local cannabis testing organization:


  • Leaves have the potential to degrade when shipping to other parts of the country.

  • Shipping costs are much more expensive.


In addition, PBL offers:

  • A validated cannabis sex detection test.

  • The turnaround time for the testing is 24 hours.

  • The cost is $15 per test.



PB Laboratories, located in Albuquerque, NM, is a state approved cannabis testing laboratory.

The organization has experience in high-throughput clinical, environmental, biomedical, and genetic testing laboratories. The team has the resources to tackle any aspect of cannabis testing.

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