Grapes and onions are the only ones I can think of to avoid. Then of course try to avoid seeds/pits. I’d agree w Patty – try to stick with things that are high in nutrients. Might be good to avoid tomatoes, many dogs are sensitive to them.
I honestly don’t add much to my dogs’ kibble, but every summer, the dogs get all the apples they want (assuming the cow doesn’t gobble them up first!), and they get veggie leftovers. If you have picky eaters, pureeing them might help. Freezing would be good if you want to stock up when produce is on sale. One of my boys is EXTRA picky about what goes in his mouth, so if I got him started on veggies, I’d probably add a bit of home made chicken stock to hide the icky healthy taste ;D
