Dear Cheri,

I recently started growing cannabis and I wanted some advice on how to tell when cannabis plants are ready to harvest.  And specifically, how to tell if you let a marijuana plant grow too long?  I suspect I might have.

Those are great questions.  To some degree exactly when you harvest is a matter of preference and how to tell when cannabis plants are ready to harvest is a hotly debated topic on internet cannabis growing boards. 

That said there is general agreement and in the video above, Cannabis Cheri’s grow editor Mitch Mandell shares his preferences.

Know that you won’t be able to tell with the naked eye because you need to see the plant’s trichomes, the tiny microscopic glands that contain the cannabinoids covering the plants. 

It’s the color of the trichomes that tell you what you need to know.  You might think you can see them well enough with the naked eye, but trust me, you can’t.  Pick up a lighted jeweler’s loupe  or a digital microscope to properly examine your cannabis plants.

In immature plants the trichomes will be clear. 

As the plant matures and nears harvest time the trichomes turn and opaque milky white. 

With more time, the trichomes turn amber.  Mitch likes to harvest just when the base is just starting to turn amber.  And keep in mind we are talking about the microscopic trichomes, NOT the little red hairs you sometimes see.

If a plant is fully amber, you let it go too long by most people’s standards.  You can still use it but expect more sleepy or couch-locked effects, which may or may not be a bad thing depending on how you use cannabis.