A quick web search will bring up all kinds of myths about how to tell female cannabis seeds from males. One of the most popular ones comes from a chart showing 5 different seeds that claims that the female seeds have “a perfectly round volcano-like depression at the bottom (from where the seed was attached to the plant).”
It’s important to only conduct this test if you are planning to germinate the seeds immediately afterwards. The viable seeds that sunk to the bottom of the glass will have taken in water, crossing the membrane of the seed and signalling that it’s time to come to life—activating germination.
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
The one true method to test the genetic potential of a seed is to simply put it in the soil. It won’t take too long to see the results. This option is best for the hobby home grower who has time and space to spare for a risky project. Growers cultivating cannabis for commercial use likely don’t have the excess time to invest.
Keep in mind that the simple process of packaging and storing cannabis seeds can also affect their appearance. Abrupt changes in humidity, temperature, or light exposure can make some seeds appear darker or lighter than others, but ultimately have no effect on their quality.
Remember, just like animals and other living things, cannabis seeds are biologically different from one another (even if they are technically the same strain) and therefore will exhibit different physical characteristics. Don’t let these natural differences fool you into thinking that a larger, rounder, and darker seed (for example) is of better quality than a lighter, smaller, and more oval-shaped one.
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.
Having male cannabis plants in your garden is basically a recipe for disaster, so you want to avoid it at all costs. By the way, here’s how to figure out if your plants are male or female.
Cannabis seeds are surprisingly beautiful. They have a mottled brown appearance with patches of light and dark, and sometimes gorgeous tiger stripes. The seeds are also quite shiny if you view them close enough.
How to Test Cannabis Seeds
After germination, you’re good to go. Remember to check back as the plants mature to make sure you haven’t got any male cannabis plants.
In some instances, you can crack the seed open and see inside if you can’t tell anything from the outer shell. An oily inside with a musty smell means that the seed has gone bad. Similarly, black inside the seed means that it’s fermenting. Again, it won’t germinate in this instance.
There are several easy methods for testing cannabis seeds. Most of them can be performed before germination, saving you some time and resources. Let’s find out how to check your seeds.
1. Appearance & Color
2. Size & Shape
If you know how old the (fully mature) seeds are you’ll be able to have a better idea of viable they are. Like all genetic material, seeds degrade over time, so freshly harvested seeds are often more viable than ones that are months or years old. You should store seeds in a cool, dark place (even a freezer) so they don’t rot or get mold.
You can identify quality cannabis seeds by their size and shape, especially when you can compare several seeds side-by-side. The largest seeds with the most symmetrical round or teardrop-shape are the best quality, while immature seeds are small and often have an irregular shape.
High-quality seeds have certain aesthetic qualities that set them apart from seeds that aren’t as healthy. The most viable seeds are brown, tan, or even black, as immature seeds are lighter colors like white, yellow, and pale green. Some people even claim that the best seeds feature dark spots or stripe patterns and that there should be a healthy sheen on the surface when held under light, like a fresh coat of wax.