Soft Secrets: Sex is Everything!

Pre-flowering

Pre-flowers, described by Robert Clarke in Marijuana Botany as "primordial," are the first indication of a plant's sex. The pre-flowers grow at branch internodes just behind the leaf spur or stipule about the fourth week of vegetative growth, when the plant is six to eight weeks old. This is the point of sexual maturity, the first sign a plant is preparing for flowering–the next stage in life.

You can see pre-flowers with the naked eye, but a 10 to 30X magnifier will make viewing easier. You can accurately determine plant sex after eight weeks. Using this method, you can distinguish sex before inducing flowering.

Image shows a male plant after 24 days of vegetative growth at 18/6 day/night. Staminate flowers are located at the node between the stipule and emerging branch.

Early male flowers are easy to spot with the naked eye. They are located at branch internodes.

Male pollen sacks hang like little balls. Each pollen sac has enough pollen to pollinate all the females in the average grow room.

Male Pre-flowering

Male pre-flowers are normally visible when plants are six to eight weeks old, after the fourth week of vegetative growth. The preflowers emerge behind the stipule at the fourth to fifth branch internodes and generally do not turn into full flowers. But, according to Bongaloid (www.overgrow.com), "a male plant will develop mature staminate flowers after prolonged periods of vegetative growth."

Always wait to induce flowering until after pre-flowers appear. Inducing flowering with 12 hours of uninterrupted darkness and 12 hours of light before pre-flowers develop will stress the plant. This stress could cause peculiar growth, and plants might develop into hermaphrodites. Inducing flowering before pre-flowers form will not expedite flowering. In fact, flowering will occur at about the same time as if you had waited for preflowers to show! Plants grown from seed under an 18/6 day/night photoperiod will generally show pre-flowers before plants that are given a 24/0 day/night photoperiod. Once preflowers are distinguishable as male or female, plants can be induced to flower with a 12/12 day/night photoperiod.

Male flowers develop quickly on the tip of this male plant. Keep an eye out for male plants, and separate them from females as soon as they are spotted.

This male plant is in full bloom. Flowers open over the course of a week or longer to ensure females are completely pollinated.

Grains of pollen are miniscule. This close-up of a grain of male pollen is magnified 4000 times. Eirik (www.overgrow.com) captured this image on a scanning electron microscope.

A word of caution from bc-trichome-farmer (www.overgrow.com): "Do not try to sex a seedling based on the very first pre-flower. Wait and make sure. The time between using a 25X (loupe) to spot the very first pre-flower and the plant dropping pollen is at least 10+ days away, so it's safe."

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