Ah, pollination: plants wouldn’t be around if they didn’t know how to reproduce. That’s a given, but when you’re growing it may sometimes seem like the garden’s doing everything it can to work against you- especially when it’s time to grow new plants.
Given all the natural conditions it takes to make sure pollen gets into a flower, pollination seems like blind luck. When it comes to indoor growing, though, pollination can be less of a miracle and more of a pain when pollen’s available but nothing’s turning out seeds.
Whether your plants reproduce by wind pollination, carrier pollination (like bee’s and animals), we manually pollinate them, or they pollinate themselves when your plants can’t pollinate they can’t produce seeds. That may be desirable to some, but for growers who aren’t the biggest fans of cloning, seed production is key.
Self-Pollination, Cross Pollination, and the Importance of Airflow
There are all sorts of ways pollen gets into plants, but pollination essentially comes down to two techniques: self-pollination and cross-pollination. The male organs of a flower help produce, collect, and release pollen that’s then collected female flowers. The female organs of the flower help trap the pollen and send it to its ovule. In cross-pollinated plants, the pollen is usually carried from a male to a female by wind, by animals, by insects, or it can be done manually. But in self-pollinated plants, those organs exist within the same flower, and with a little bit of movement from the wind or animals, the pollen it creates travels down into its own ovule. From there it creates the pod the seeds will be housed in.
The key factor of pollination is air movement. Whether a plant releases pollen into the air or releases it to itself, if there is no wind to help spread pollen- or if a self-pollinating plant can’t get its pollen into its ovule- pollination won’t occur. Pollination won’t happen by simply having male and females next to each other, and won’t happen on its own simply because the plant is self-pollinating. If a plant sends pollen into the air, the only way it’ll get to another plant is by the wind. At the same time, when a plant has what it needs to pollinate itself, wind movement will help make pollen available to the flower while helping that pollen move down into the ovule.
If you can add a gentle breeze across your canopy to help spread pollen or shake it loose you can get pollination started or get it back on track. You can also help pollinate plants manually by moving pollen from one plant into another, or by gently shaking pollen loose for self-pollinators.
What to do When Your Plants Won’t Pollinate
If your plant needs a little help pollinating you can intervene, but how do you know when to do so? When it comes to determining the right time to pollinate you’ve got to consider what’s best for your plant species and the type of pollination it’s used to.
For self-pollinating plants, nature takes care of a majority of the pollinating process. As long as the plant’s flowers are able to produce pollen it should be able to eventually produce seeds. However, if the environment doesn’t help (no wind movement shaking up that pollen, the temperatures and humidity levels are unfavorable) you’ll need to step in. For these plants, it’s important to know when they normally produce pollen. When the time comes, the air still gives your plants a little shake and helps the pollen get to where it needs to go.
On the other hand, if your plants cross-pollinate you may want to learn the best time to pollinate female flowers. While a female may be able to receive a male’s pollen well before maturity, it may be worthwhile- in the hunt for the best seeds and fruit- to collect pollen and apply it when your female plants are more mature. Most times male plants grow faster than female plants, so while its pollen is ready to rock the female flowers may want a little more time to get as mature as possible. The more optimal the flower the better the end result will be better fruit and/or more seeds.
Manual Pollination: Taking Pollination into Your Own Hands
The same way bees get pollen all over their bodies and spread it from plant to plant, whenever we walk through fields and bushes with lots of pollen we become like that be. We collect it by simply walking through areas with high pollen content (you’d know this best if you have allergies) and when we move it shakes off on to the plants around- but that’s more of a natural, unintentional way of pollinating.
Manual pollination (pollination done by hand) takes much more thorough and intentional work.
First is the collecting of pollen. Lots of flowers have it resting on the inner part of the pedals, so collecting pollen in these cases is as simple as gathering it on the head of a q-tip or a thin paintbrush. In other cases where pollen sacks tend to burst open to release pollen- like in the case of cannabis- there are two ways to collect pollen:
Right before bursting open, pollen sacs can be collected in a small baggie. Once collected and dried, you can open the sacs and its pollen can fall out.
Alternatively, if you’d like to let the flower send off pollen naturally (which can yield more than a possible premature collection) you can surround your plant in a glass, let it send off its pollen, and collect the necessary pollen off of the glass.
If you only want to collect pollen and not pollinate your other plants, we suggest removing the plant and its case entirely from the garden and then collecting.
The second part of manual pollination is the application, and this part is pretty easy. Whether you have a brush or a q-tip, use it to apply pollen to the stigma of the female plant. If your plant self-pollinates, simply use its pollen and apply it to the stigma, and then your plant will be on its way to making seeds, pods, and fruit.
So What About Seedless Plants?
We’ve talked a lot about producing seeds, and explained that fruit (and pods) are what house those seeds. But what about fruit that harvests without seeds? Something can’t produce fruit without being pollinated, can it? But what about seedless grapes or watermelon- how do those come about?
Plants will naturally be male or female or self-pollinating, and in nature, a plant will send off its pollen to pollinate other flowers (or use its own pollen to pollinate itself). But like all things in nature, some plants’ pollen or stigma may be lacking enough genetic energy to grow seeds inside of a fruit. Instead, the pollinated plant will produce a pod/fruit and inside will be little to no seeds. When these properties are seen in a plant it will then be cloned or grafted and bred, and when it pollinates another plant its fruit will pass along the genetic trait of producing little to no seeds.
Plants and seeds can also be bred to grow fruit that does not yield seeds. For example, there’s a growing trend of “feminized” seeds that will take the guesswork out of figuring out the sex because it’s been modified and/or bred to produce fruit and harvests that do not produce pollen or seeds. In other circumstances, the plants are modified so that they produce fruit without being fertilized, and these processes usually involve taking clones and seeds from plants that exhibit those traits.