Sexing marijuana

how to tell female from male cannabis plants

Cannabis is dioecious: except in unusual circumstances, a plant will bear either male or female flowers, but not both. Only the female plants produce flowers containing desirable amounts of THC, and, if they are fertilised (i.e. pollinated by a male plant) the amount of THC is reduced as the female puts her energy into seed production instead. Because of this, it is vital to remove any male plants as early as possible.

Newbie growers often become quite anxious about sexing their marijuana plants, when actually it is easy to tell the difference between a male and female.

Male marijuana plants

wp5f2d1784_05_06-300x216As you can see, the male cannabis plant produces little “balls” of pollen which make it easy to tell – and remember. Sometimes these are more banana shaped than cylindrical. No hairs – pistils – will emerge from these.



Female marijuanahow to tell female cannabis

Instead of pollen sacs, the female plants start as individual pistils or white hairs (occasionally these may be yellow or pink tinged) protected at the base by a membranous layer, the calyx. . As flowering progresses, more and more of these pistils will form until they produce the sticky clusters that make up bud.




Tips on sexing cannabis plants:

  1. One pre-flowering indicator is growth. Male plants of the same strain and in the same environment tend to have a leggier appearance than female ones. But this should only be used as a guide: it will give you an idea of which plants to watch most closely and is not a hard and fast rule.
  2. If you don’t have a large number of marijuana plants growing, and you have the facilities, you can save time, and money on grow foods, by carefully taking labelled cuttings from each plant and using light cycles, force the rooted cuttings into flower without a growth period. To do this, you need a separate light protected area and a small light on a 12 hour darkness cycle. As soon as the cuttings show sex (1-2 weeks), remove the parent plant from either your indoor or outdoor grow.

Hermaphrodite plants

“ Hermies” are freak accidents which can ruin a crop: they produce little good value bud as they self-seed – and can pollinate true females – and also the seed is of little value either as the tendency to become hermaphrodite is passed on. Whilst each individual plant’s genetic code determines its sex, there is sufficient anecdotal evidence that extreme stress at early points in the vegetative stage can force marijuana to become hermaphrodite. Whilst there is some debate on the matter, as it is a fact that hermaphrodites are to be avoided, the best answer is to avoid unduly stressing your plants!


Feminised seeds

As there is nothing more disheartening than discovering that a statistical blip means that ¾ of your crop is male, and all that time, money and effort you spent germinating and growing marijuana has to be pulled out and burnt, its always worth considering buying feminized seeds.

Although these are more expensive to buy – a lot more work goes into their production – you are assured that all of your germinated seedlings will mature into female plants. There is also the added benefit that you can more accurately control the number of seeds you buy and the number of plants you grow. This has security implications as the law tends not to discriminate between number of plants / weight of plant matter and those which will result in a good smoke.

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