The short answer is that NOT all marigolds are edible. I don't know all the species, but as a very broad rule of thumb, opt for Calendula officinalis as the one considered the edible and medicinal ('official') marigold. It's also called Holigold, Pot Marigold, Bride of the Sun, Summer's Bride, Sun's Gold, Ruddes, Ruddles, Marygold, Marybud.

The French Marigold, Tagetes patula, is not edible. It is used in companion planting for insect and nematode control.

Of the Gem Marigolds, only Tagetes tenuifolia is edible, although some claim that T. signata and T. pumila are also edible. Since there seems to be some disagreement about this, I'd suggest caution. I've seen quite a few reference where T. signata is 'harmful if eaten in large quantities'. I've seen one or two references to the African Marigold (T. erecta) being edible.

Mexican Marigold Mint, also known by many other names including Winter Tarragon, Root Beer plant, Yerba anis or Cloud Plant (Tagetes lucida)is edible.

Some people claim that all marigolds are edible, but that some of them taste VILE! I daresay you should be guided by your nose and taste-buds with marigolds. If it smells and tastes like an insect repellent, then that is probably the best use for it!

Me - I stick with reliable Calendula and no other except for Tagetes lucida which I use as a substitute for French Tarragon. And I don't believe everything I read on the internet or in books. I prefer to play safe. When in doubt - don't.

I disagree--French Marigold (tagetes patula) flower petals are edible. The ones I use on salads are the type that have blooms with 5 wide petals, not the ones that are more half ball shaped with numerous petals. I have only used the petals, not anything else.

Maybe so but I can't imagine they are very pleasant! They are so very strong in that "marigold-ness." So much so that they are companion plants for nematode control as Daisy mentions. My mom used them as companion plants to discourage plant chewers like woodchucks from the vegetable garden.

I'd rather stick calendula. It is far more pleasant!

FataMorgana

I understand that this question is 8 years old, but since I still found it on the first page of Google search, I assume people still reading it. Contrary to the second response, Tagetis patula IS edible. To get MUCH more info, go to http://link.springer.com/book/10.1007/978-94-007-7395-0/page/2#page-1 (list of entries from volume 7 of "Edible Medicinal And Non-Medicinal Plants" by T.K. Lim), pages 456-468. You'd have to buy one Chapter for ã19.95 or the whole book for ã144.00, but luckily they'll let you read the first two pages of every single chapter for free!!! They have chapters on Tagetis erecta, T. lucida, T. patula, and T. tenuifolia. I am seriously tempted to buy this book, honestly: it's full of all kind of information (Scientific name, Synonyms, Family, Common/English Names, Vernacular Names, Origin/Distribution, Agroecology, Edible Plant Parts and Uses, Botany, Nutritive/Medicinal Properties, Photos, and apparently 10 more pages of other info!

I understand that this question is 8 years old, but since I still found it on the first page of Google search, I assume people still reading it. Contrary to the second response, Tagetis patula IS edible. To get MUCH more info, go to http://link.springer.com/book/10.1007/978-94-007-7395-0/page/2#page-1 (list of entries from volume 7 of "Edible Medicinal And Non-Medicinal Plants" by T.K. Lim), pages 456-468. You'd have to buy one Chapter for ã19.95 or the whole book for ã144.00, but luckily they'll let you read the first two pages of every single chapter for free!!! They have chapters on Tagetis erecta, T. lucida, T. patula, and T. tenuifolia. I am seriously tempted to buy this book, honestly: it's full of all kind of information (Scientific name, Synonyms, Family, Common/English Names, Vernacular Names, Origin/Distribution, Agroecology, Edible Plant Parts and Uses, Botany, Nutritive/Medicinal Properties, Photos, and apparently 10 more pages of other info!