Gendering Your Marijuana Plant
As any cannabis connoisseur can tell you, an all-female crop produces the finest bud of all. It’s true, and the reason is pretty simple: when females are left unfertilized (i.e. they never come into contact with the pollen from male flowers) they devote all their energy and resources to producing buds that are encrusted with trichomes and sticky, thick resin, rather than into seeds. This is why gendering your crop is so important.
The term for a crop of all-female plants is sensimilla, which derives from the Spanish ‘sin semilla’ and literally means ‘without seeds’. If you have access to clones or pre-gendered starter plants, then growing a crop of all-female plants is easy to achieve. This is part of why cloning is such a popular technique, aside from the fact that it allows you to reproduce a genetically identical plant from a mother you know to produce good bud.
Most first-time growers start with seeds, though, and this means you’ll be playing a bit of Russian Roulette, as it were. Assuming odds of roughly 50/50, you can expect that half the seeds you plant will be male. In reality, you might end up with 80% that are male, or even 100%. It really depends on how many seeds you plant.
If you plant 10 seeds, you have good odds of getting at least 2 – 3 female plants, possibly more. You could also end up with 80% of your plants being female, which means you can celebrate. But wait just a second, because how on earth can you tell what gender your plant is?
At first, the answer is that you can’t. As frustrating as it may be, if you’re starting from seed you will have to wait at least 6 – 8 weeks before you can successfully gender your seedlings. Ideally, the best time to gender them is at 3 – 4 months of age, when you’re ready to initiate flowering.
To gender your plants, you can selectively induce flowering on a specific limb. You’ll need to reference some photos if you’ve never seen it before, but what you’ll be looking for is the developing pistles on a female plant or the calyx of a male plant.
To selectively induce flowering, choose a specific limb and slide a paper towel tube over it for 12 hours of each day, to simulate night-time. Allow the limb 12 hours of light, and within 1 – 2 weeks you should see the beginning a calyx or a pistle in the node of the branch.
Toss the males you identify, and continue on with your females. Keep a sharp eye on them, though, just in case you missed a boy. Alternatively, you can simply put your whole crop in to flower and watch each plant on a daily basis, removing males the instant you spot them.
It’s a little risky to leave males in while inducing full-fledged flowering, so make sure you are checking your plants thoroughly every single day. If you spot the male too late (i.e. his flowers have shown up and opened, which can happen very quickly) your whole crop could already be pollinated and you won’t be able to do a thing about it.