The 3 per seed mod is the best and easiest way to create seeds that have a higher chance of producing fruits. It is based on a simple principle: every plant can be split into three parts, and every part has a certain chance of producing a fruit. If you try to split a plant into three parts and get a fruit from each of them, you will have a higher chance of getting a fruit if you get seeds from this mod.

You don't need to do anything special to get seeds. All you need to do is to destroy a certain number of plants.