I don't ever use any brassica in stock (only in soup), nor any part of a potato. Leek tops are great, though, and celery leaves, etc.

With regards to brassica, I also do not use them in stock, except for turnips and rutabagas, but only the roots. I do not use any brassica stems or leaves in stock. If I do use turnips or rutabagas, I use them sparingly and only when I do not have parsnips. I like turnip greens but I never put them in stock.

celery, onion, carrot, garlic, leek green tops, (i usually freeze them for stock). Garlic i chop in half all the inner tiny annoying ones. peppercorns, a couple bay leaves. Best kept simple.

I go ahead and use a whole onion quartered, couple whole carrots, celery.

Any herbs go in the last 1/2hr-45 of cooking. Parsley, thyme, chives...simple mild ones.

Only a pure veggie stock do i branch out a bit. Cautiously as some are a bit aggressive and can become bitter. Not simmered more than an hour for veg. 2max

I've got a veg on now and it has lots of root ends. Among the usuals.

You must have missed reading a copy of "Nourishing Broth" by Sally Fallon Morell and Kaayla T. Daniel, PhD, CCN. A book loaded with information and recipes. The Cliffs Notes version is found here: Broth is Beautiful - http://www.westonaprice.org/health-topics/broth-is-beautiful/ 

I pretty much like bone broth without a lot of other things in it. I can't/don't use onion or garlic in anything anymore, since gallbladder surgery, so even those two are not necessary. I usually add some carrots and celery (be careful, the celery ends and leaves can be bitter), and some parsley or parsley stems (if I happen to have a bundle of them), and that's about it for the bone broth I make.

If I want to make vegetable broth, that's a completely different "beast". I learned to make vegetable broth from trimmings and less-than-perfect vegetables when I went on a macrobiotic diet back in the late 1980's, and made it a habit ever since. In vegetable broth I avoid foods from the brassica family --- broccoli, cabbage, Brussels sprouts, cauliflower, kale, rutabagas, and turnips, which give a strong/bitter flavor. A few outer cabbage leaves are okay, but I wouldn't use a lot of them. Artichokes are also too strong for broth. I avoid using corn because it can make the broth cloudy (from the starch).

For both bone broth and vegetable broth, avoid using dried/powdered versions of herbs - FRESH IS BEST!

-Grainlady

I don't put vegetables in bone broth either.

For stock I never put in garlic, which can make it taste musty or bitter, though the garlic adjacent trimmings you mentioned should be fine. I do use rutabaga and turnip but not the greens. I would use the greens in a soup, but there seems to be a point in the boiling down where greens stop tasting fresh, like they're decaying. I do strain my stocks, however, so there aren't starchy bits from the roots floating around. I also use celery root, celery stalks, carrots, onions, and parsnips. For vegetable stock, I use all the same veg, with more onions, plus whatever is wilting in the fridge--bell peppers, chili peppers, scallions, etc. Even tomatoes. And sometimes herbs at the end.

For low FODMAP chicken stock, which can't have onions, I used rutabagas, turnips, parsnips, carrots, parsley, some fennel greens and bay leaves, as well as some green beans. I boiled down the chicken pieces first, before adding the greens, and it was okay--at least it has flavor--but I still don't like the boiled greens taste. When using the stock for making dishes, rather than soups, however, it wasn't strong enough to be an issue.

Summary: No garlic. No cabbagy or cruciferous (high sulphur). No green leaves/stems (other than celery leaves which aren't all that green), unless at the very end.

No green anything from potatoes, tomatoes, eggplants or anything else in that family. For broth I tend to be simple - celery carrots and onion (leek) - maybe tomatoes. No brassicas. Garlic might be in a soup made with the broth but not usually the broth.

The more stuff you put in the more flavorful it is....with the exception of things that are toxic...like green potato peelings and potato sprouts. Everything you put in affects the flavor and adds it's own particular personality.
I can't imagine making any sort of broth or stock without garlic or onions....or both.

Interesting the differences. Garlic is in all my stocks. Simmered garlic is very mild. A well known NewOrleans garlic soup is a broth of 12 cloves of garlic, the entire cloves, shallots, leeks, celery. Strain and chill. Then continue with the fresh ingredients for the final delish.

Made a veg stock last night while prepping dinner, then made a lobster stock, chilled it and reducing that now with leeks garlic shallots. So i think as mentioned by many above, keep it simple especially at first. Avoid any strong leaves and greens....save those for soups fresh wilted later on...celery leaves are always welcome in stock.

Bone broth does not really need 'extras' but i do, especially if having a cup pre-meal or for lunch. I stock chicken and duck paws in the freezer for bone broth. I still like the added celery, garlic, shallot, leek for added flavor.

Lots of variations but very basic 'no adds' mentioned above.

I also add garlic to all my stock, as well as onion, celery and carrot. Sometimes I put in parsnip, but not too much because it's so sweet. I've also added bits of turnip or rutabaga, but not usually because I usually just don't have it. Black pepper corns, always a bay leaf, not potato because it just turns to mush. So no beets because of the ugly color, no potato because it's mushy, no tomato for the same reason, no greens like kale or cabbage because they are too strong. If it's strictly vegetable stock, then those "rules" go out the window and it all goes in!

So, for stock here, pretty much anything goes, depending on the flavor I'm looking for in the stock.

Annie