Some smokers might be pleased to see some cannabis seeds in their bag, and might think themselves lucky. However, finding seeds in a bag is bad for various reasons. For one, this means the grower has messed up and allowed their female plants to be pollinated by an invading male. When flowers are pollinated, they stop producing THC-containing resin and divert their energy toward producing seeds. Secondly, the seeds will have added to the overall weight of the bag, which means less weed for your buck.
Immature cannabis seeds, on the other hand, tend to be green and have a soft outer shell that breaks when any kind of pressure is applied to it.
This simple and cost-effective method is a great way to tell the good genetics from the bad; they will sink or swim, literally. Seeds that remain buoyant on the surface are more than likely of poor quality and are to be discarded. Seeds that sink to the bottom like a botanical cannonball are probably healthy and should be germinated.
Germinating All Your Seeds Regardless
However, slight patience is required when conducting the float test, as results are not immediately apparent. You’ll have to wait for approximately 1–2 hours before confirming the results. Some good-quality seeds will need adequate time to absorb enough water for them to sink. Use this time to go water the garden and get some much needed pruning done. Upon your return, any seeds that remain on the surface are most likely not viable and won’t be worth further time and effort.
Unlike other agricultural crops (like vegetables, fruit, or grain), cannabis hasn’t undergone the vigorous breeding techniques that ensure a stable crop. This means that you’ll sometimes sow a pack of seeds technically labeled as the same “strain,” but may end up with very different looking plants. It also means that the individual seeds you buy from a seed bank can vary in appearance.
The alternative to this is to risk buying seeds from a hobbyist. This isn’t to say that hobby growers cannot produce fantastic genetics, but if you don’t know them or their skills, there’s no way to know whether your seeds will grow.
This is absolutely not true. As we explained earlier, cannabis seeds naturally look different, and no single physical trait of a seed can tell you whether that seed contains the genetics for a male or female plant. The only way to tell a female cannabis plant from a male is by looking at its flowers when it begins to sex. Don’t be fooled into throwing out perfectly healthy seeds just because a popular internet chart told you so.
Most cannabis soils, with the exception of special soil mixes used for propagation and seedlings, are pre-fertilised. This way, you won’t have to administer nutrients until several weeks into the grow. In fact, you may only need to feed nutrients when your plants start to flower. If for some reason your growing medium isn’t pre-fertilised, you will have to give nutrients to your plants from the beginning.
Use some type of absorbent paper (kitchen paper, coffee filter) and place a couple sheets on a flat surface such as a plate. Put your seeds on the paper, spaced a little apart, and cover with a couple more sheets over the top. Moisten the paper and make sure to keep it damp so it doesn’t dry out. After a few days, when the seeds have sprouted 2–3mm taproots, transfer them to their seedling pots.
4. NOT USING PROPER POTS
Some grows fail before seeds even have a chance to sprout, as growers tend to make mistakes when germinating seeds.
Fill a small seedling pot with an unfertilised or “light” potting mix. Poke a small hole about 1cm deep in the middle and place your seed inside. Cover lightly with soil. Water the soil and cover the seedling pot with clingfilm to lock in moisture. Seeds should germinate in a few days.
It does happen: Someone hands you a bag of seeds of “some great weed” for you to grow. You’re happy since you just saved some cash on seeds. The problem is, you don’t know what type of cannabis the seeds are, whether it’s sativa, indica, autoflowers, etc. We’re already off to a pretty bad start.
Through cloning, you can create a new harvest with exact replicas of your favorite plant. Because genetics are identical, a clone will give you a plant with the same characteristics as the mother, such as flavor, cannabinoid profile, yield, grow time, etc. So if you come across a specific strain or phenotype you really like, you might want to clone it to reproduce more buds that have the same effects and characteristics.
The main drawback to growing from seed is there is no guarantee as to what you’ll end up with—if you buy a regular pack of cannabis seeds, it will be a mix of males and females. You’ll need to sex them out (more below) to identify the males and get rid of them, because you don’t want your females producing seeds.
What are feminized cannabis seeds?
Take four sheets of paper towels and soak them with distilled water. The towels should be soaked but shouldn’t have excess water running off.
Check out Johanna’s full video series on how to grow weed on Leafly’s YouTube .
Some varieties of cannabis can produce male parts alongside female flowers on the same plant, especially if exposed to environmental stressors. These plants are known as hermaphrodites, and sometimes they can self-pollinate to create seeds.