Every website that legally sells marijuana seeds offers a curious option to buy so called feminized seeds, usually at two or three times the price for the same quantity of ordinary seeds. But what are feminized marijuana seeds? And why do people buy them if they cost much more?

What are they?

Marijuana plants are either male or female – the male produces flowers that fertilize the female plant, which develops buds and seeds. A standard pack of cheap marijuana seeds will produce a mixture of male and female plants in a roughly 50/50 ratio.

Feminized marijuana seeds are produced by cloning and "shocking" female plants by spraying them with a silver solution. This prevents them from developing as males. The seeds from plants that have been treated in this way will only produce female plants – hence they are called feminized marijuana seeds.

Why do people buy them?

There are number of reasons why many experienced growers choose to buy feminized marijuana seeds. Most male plants have very low levels of THC, so they cannot be harvested for marijuana. Furthermore, if a crop has a mixture of sexes it is necessary to identify and separate the male plants as soon as possible to make sure they do not fertilize the females – unfertilized female plants produce bigger, riper buds, while fertilized females produce smaller buds that are filled with marijuana seeds. Good growing can still be done with ordinary seeds and mixed sex plants, but it can take a lot more effort, and yields can vary greatly.

Feminized marijuana seeds will produce all female plants. This saves this hassle of identifying and separating the male plants in a crop before they can fertilize the females, and it also means that out of a pack of ten seeds it is possible to produce ten plants that can be harvested for marijuana rather than (on average) five plants. Most growers will naturally have a limited amount of space, and a guaranteed all female crop can help to make the most of a smaller growing space.

Of course, growers want to produce more plants without having to repeatedly buy marijuana seeds, but it is possible to do this without breeding plants – more experienced growers prefer to clone their plants by taking a good cutting from a mature plant and then replanting it. Not only does this allow them to maintain unfertilized females and maintain a high yield from all their plants, the clone will maintain all the characteristics of its "parent", meaning that the best quality plants can be reproduced exactly.

They cost buyers more. Cheap marijuana seeds can be produced very easily, but it takes some serious time and effort to produce feminized marijuana seeds. Since these seeds produce more valuable plants, they are consequently more expensive. But they remain popular amongst growers. They save growers the trouble of identifying and separating the male plants, and also give a guaranteed female from every marijuana seed that is bought, leading to more buds and higher yields.