How to Pollinate Cannabis Plants

As people progress and gain experience with all the different aspects of cannabis cultivation, they invariably get to a point where they wish to cultivate their own seed. Despite all the great work by the big seedbanks that has resulted in the thousands of quality cannabis strains that are available today, seeds tend to be very expensive and this can be prohibitive when budgets are tight.

Producing your own seeds is a relatively simple task. Indeed, many growers have produced them by mistake, much to their dismay. It is essential that you take control of this process, producing either seeded plants, or sensimillia, as and when you wish.

First off, let’s have a short 101 on the cannabis life cycle so we all know we’re singing from the same sheet. Conventional cannabis cultivation has us remove all males as soon as they exhibit sexual traits. This means that the females remain unpollinated, essentially ‘virgins’, and put their energy into THC and resin production rather than seed production. The result is sensimillia, literally meaning “without seed”.  If a female plant does become pollinated she will produce abundant seeds. This does not mean that the plant is wasted, despite the fact that many growers trash accidently pollinated plants. Your seed bearing female is still useful to smoke, most of us have bought weed with seeds at some time. It’s just that sensimillia is better!

In the wild cannabis is essentially a wind pollinated species, although there may be a minor part played by some animals. Male plants will come into flower just before the females and will form flowers over a period of several days, ensuring that there is some overlap between the male and female flowering times so that they can be sure to be producing pollen at the correct time.

If you wish to collect pollen from your male plants it is important to keep a good eye on the sex of your plants. Pollinating all the plants in your grow room is not a problem but if you wish to control it and leave some of the females unpollinated, you will need to remove males as soon as you identify them. Put them in a separate room as far from the room with the females as possible. Unwanted pollination of female plants can occur with heart breaking regularity. That pollen has a great knack of getting to the females and you should ensure the utmost hygiene, changing clothes and washing hands when moving between rooms. Fans should always be turned off when dealing with pollen.

Having isolated your males you can begin collecting their pollen. Attach a paper bag over the end of a flowering branch on your chosen male plant. If collecting pollen for cross breeding you will have selected the male with the most desirable characteristics. A bag with a clear plastic window can be useful here, enabling you to see the pollen collecting.

Tape the bag around the stem so that it is completely sealed and then pinch a hole in the top corner to allow the branch to breath. Once a day pinch the breather hole shut and give the branch a good shake. You should be able to see the pollen begin to accumulate in the corner of the bag. Continue this process for a week or so.

Now cut the branch off below where the bag is attached. Tear open the top of the bag and remove the male flowers. At the bottom of the bag will be the pollen and some other bits and pieces of detritus. Pour the pollen into a ziplock bag, seal it and store it in the fridge.

Now it is time to pollinate our female. When the selected female is ready and her flowers have developed long pistils, invert the ziplock bag over the end of the cola. You will see the pollen attach itself to the flowers.

In some cases you may wish to pollinate individual female flowers. This is easily achieved by using a soft paint brush or cosmetics brush to gently apply the pollen directly to the flower.

And that is literally all there is to it. Once pollinated your female flowers will go straight into seed production and you will see the calyxes swelling with seeds. Do not be tempted by impatience. Seeds are not mature until they darken in colour. It is best to wait until the calyxes begin to open, seeds will pop out easily. Actual seed colours may vary from strain to strain but you are looking for dark brown or tiger striped. Light green or tan seeds are not ready.

Once you have harvested your seeds you should air dry them for a week or two. They may then be stored (a film canister is ideal) until required.