Growing Hemp: How to Identify the Sex of Your Plants

My first year of farming hemp was filled with lots of anxiety about correctly identifying male flowers. 

I quickly learned that sexing plants are crucial to harvesting premium flower. It will make a difference when trying to land a buyer or getting the value your hemp crop deserves. 

Learning how to identify the early stages of flowering and identifying male vs. female flowers will hopefully relieve you of the same anxiety.

The Impact of Seeds and Pollen

If you are a connoisseur in the hemp/Cannabis world, you already know that seeds in your flower directly affect the buds' quality. 

Seeds take away from the Cannabinoid content of each flower and make the flower less favorable for smoking as each seed must be removed. 

Producing sinsemilla, or high-quality seedless buds starts with the farmer's eye and culling male plants.

Industrial hemp plants are typically male; however, you do not want a male plant to produce flowers. 

Most hemp plants are dioecious (separate male and female plants), with the rare exception of a stressed plant becoming a hermaphrodite. 

Once a male plant or hermaphroditic plant starts producing pollen, this pollen will cross-pollinate any female flower it touches, and one plant's pollen can travel to pollinate over 100 plants, and even in fields of hemp miles away

picture-of-hemp-field


Where to look

Once the hemp plants are triggered internally into flower mode, the plant's genetic code is to create flowers at each node, especially the young ones toward the top of the plant. 

A node is the corner/intersection where a young stem or leaf meets the attached branch, and internodes are the spaces of the branch between each node. 

Stipules (tiny green thorn-like leaves that will grow at the base of the flower/node) are formed at each node when flowering. 

These nodes are where you'll be looking for pre-flower signs and where the distinction is made for male pre-flowers vs. female.

A magnifying glass/jewelers loupe is very handy for identifying sex and can help you identify gender earlier as the signs start out incredibly small. 

Stressed plants should be the first ones you check (again, stress can lead to hermaphrodites). Male plants typically are taller, so this can be another sign to help with identification, but not always.

What to look for

Once you have seen male pre-flowers and female pre-flowers regularly, identification becomes much more natural and second nature. 

The female flowers will start off as a tiny stipule at the node with a small protruding white 'hair' above it, usually perpendicular to the stem. 

This wispy white 'hair' will grow to become the flower bud's pistol, and it is typically accompanied by a pair of tiny leaves at the base called bracts.

The male pre-flowers will look like spade-shaped balls, typically in pairs, at the node (no pun intended) and generally are much less white in color than a female pre-flower. 

These balls will grow into larger male pollen sacs. 

The white hair from a female pre-flower can be easily identified under a magnifying glass as they literally look like thick white hairs with 'bristles' all along with them. 

If you're unsure, keep a close eye and wait another day.

Conclusion

When trying to sex an entire hemp field, time is very precious as a male flower can begin producing pollen as little as 1-2 weeks after being triggered into flowering, whereas females can be 3-4 weeks before being visually noticeable. 

It is essential to stay vigilant and check your plants regularly as they grow. 

As I said, sexing your plants is the key to creating the highest quality flower and will impact the value your hemp plants deserve. 

If you ever are unsure or need help identifying, reach out to us, and one of our Hemp Resource Agents will be glad to assist you!

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We want each farmer to feel supported as if they have their own consultant, on-call, that leads them through their growing season and post-harvest solutions. Our Hemp Resource Team can suggest Integrative Pest Management Solutions and the Nutrients/Amendments you need for a successful harvest.