In the Witcher 3, there are alchemy ingredients littered all over the map. From the in game tutorials though, it states you only need to create a potion once, and then after that, when you meditate, alcohol will refill your potions automatically. So what am I supposed to do with all the extra alchemy ingredients?
If you meditate with hard alcohol, then any potion, oil, or bomb (basically most quick-action consumables) you've previously crafted will refill. This doesn't work obviously for mutagens and components Just be sure to meditate in a safe spot. Wine doesn't work, it has to be hard liquor.
If you craft a mutagen potion, it will forever refill in this way. This is a direct response to Dragon Age: Inquisitions need to have you gather herbs endlessly to keep making health potions. You only have to craft a potion once.
Well there are tons and tons of diagrams for new potions so all those ingredients can go for those new potions. And now you need a lot more ingredients to make a potion so it isn't bad gathering ingredients.
If you don't need them go ahead and sell them for some extra orens.