Male Flowering

Marijuana Horticulture

by Jorge Cervantes

When given a 12/12 day/night photoperiod, male cannabis reaches maturity and flowers one to two weeks before females. However, male plants do not necessarily need a 12/12 day/night photoperiod to dawn flowers and shed pollen. Males can flower under long days and short nights as well, but they generally produce fewer flowers.

Once male calyxes show, pollen develops quickly and can disperse within a very short time. There is always an early opener that shed pollen, often within 24 hours or less! To avoid pollination problems, remove males as soon as they are distinguished. If growing male plants, always isolate them from females, so they will not be pollinated.

Males continue flowering and shedding yellowish, dust-like pollen from bell-shaped pollen sacks well into females’ flowering stage, which ensures pollination. If you are making seeds, pollinating females too early, before the girls have developed many receptive female pistils, will result in a small seed crop.

Male flowers are about one quarter inch long and pastel green to yellowish in color. Flowers first develop near the top of the plant. Pollen sacks develop on a short spike and hang in clusters at the base of branches. Gradually, flowers develop towards the bottom of the plant. After two to six weeks of the 12-hour photoperiod, fully formed floral sacks split open and shed pollen.

Males are usually taller than female and have stout stems, sporadic branching, and fewer leaves. In nature, wind and gravity carry pollen from taller males to fertilize (pollinate) receptive females. Male plants produce fewer flowers than females, because one male plant can pollinate many females. Males also contain less THC and overall lower cannabinoid levels.

Males fertilize females, causing them to stop high THC production and start seed formation. Remove and destroy males, except those used for breeding, as soon as their sex has been determined. The instant they show sex, separate male plants used for breeding from females. Do not let them shed pollen. Premature pollen sacks often form and open early or are hidden under foliage and go unnoticed until it is too late. If growing from seed, take special care to ferret out male flowers and plants.

Growers have reported that bouncing photoperiod around and dynamically raising or lowering the temperature have the effect of producing more male plants. Note that each stimulus involves creating a climate that causes plants to suffer stress. Also, the stressful environment does not necessarily turn the entire plant male; it turn it hermaphrodite. The most susceptible plants already have a predisposition to hermaphrodism.

There are several ways to promote male or female plants during seedling growth. During vegetative growth you can get a good idea of a plant’s sex from its genetic background and growth characteristics. The most dependable way to deduce sex is “Cloning for Sex”.