I make my own, or buy some locally made tinctures. If I need something off the shelf I do buy Ed's HerbPharm stuff. Mostly because when I lived in Oregon I was in an herb group and Ed Smith was in that group. I would also buy Eclectic institute products.
As for where I get the herbs for the most part I wild craft, only what is local and abundant. I use to live where Saint John'swort was abundant but it doesn't really grow here, so I have had fresh gathered shipped in so I can process it, I have also had the good fortune to have family make some SJW oil and just ship it to me. as for methods of tincturing I use Michael Moore's info on that. Once and if I am lucky 2x in a year I can gather fresh shepherd's purse to make a fresh tincture - it's shelf life is suppose to be 6 months .
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