The F1 mark refers to plants that are the direct result of a cross between two previous pure, or landrace, cannabis genetics that occur naturally in certain areas of the world.
F1 hybrid cannabis plants are very popular, especially because they are able to express in the resulting plant the strongest characteristics inherited from the previous parents.

The most famous examples of F1 cannabis hybrids are the famous , the famous and the legendary Northern Lights. The Sensi Seeds seed bank is distinguished by the fact that it exclusively sells F1 cannabis hybrids.