A note to start, I am a new DM with little experience.
My group is far from being a bigger city and is running out of healing potions. One of my players has competition with the herbalist's kit and asked me if I could collect the ingredients and prepare a healing potion.
I like the idea behind this. I have similar experiences of computer games. For example, I played an MMORPG online for quite some time, where you can choose a profession and in your adventures collect ingredients for your profession. If I had the recipes for them, I could create objects from them. The recipes also had to be found or bought somewhere.
So I looked for the rules, but they are pretty naked about this. The Xanathar Guide states that, given a herbalism kit, a common healing potion takes a day of work to prepare and 25 gp. (also mentioned in this answer SO) I am not sure what your player should do with gold. I doubt it is an ingredient. Also, the tree next to him doesn't seem too interested to turn it into herbs.
So I searched online and found some homemade guides like here and here. They include rules to collect herbs and recipes to combine them.
However, as far as I know, it could be an unproven theory. Apparently it is not commonly used in campaigns. Why is that so? I am looking for experience with this type of crafts. Have you done something similar in your campaign and how did it go?
What other good sources on this topic exist? Maybe there are some previous editions of DnD that I didn't find?