Plant Sexing

I want to start this topic to discuss different methods for sexing Cannabis Plants. There’s a company called Phylos Bioscience that does plant sexing, and requires a sample from the Cotyledon leaf. You take the leaf and mash it between a paper test card then mail it for testing. Results are quick and available within days on their website when you log into your account.

Does anyone else know of any other companies or methods to determine plant sex prior to maturation?


I’ve seen this service before. This could really save a lot of time if you are starting a new commercial grow from seed.


We have a relationship with them and refer people regularly.

Great people doing great science.


Casey from @yerbabuena has used them. I sent them an invite to join the forum.


On their website they say you can only send in samples of the Cotyledon. I have some immature plants that no longer have cotyledon leaves that I’d like to test. Is this just the formal policy, since you’re mailing the sample cards across state lines? If I use a fan leaf as a sample will it get rejected? Anyone know the answer? The leaf material isn’t actually sent, the leaf is smashed between the sample card and essentially the juice from the plant is used for the test. The organic material is removed after you smash it into the test card.


Gary, call them at 1-844-657-4956 or email them at I’m sure they’d love to answer.

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