That avocado pit, sprouting garlic clove, or tomato sitting on your kitchen counter may look like the beginning of a free garden. Sometimes it actually is—but social media videos can make growing plants from grocery store produce look far easier and more productive than it really is. Some kitchen scraps can produce useful new growth, while others may take years to bear fruit, fail to resemble the produce they came from, or introduce disease into your garden. Even seeds that germinate successfully aren’t guaranteed to produce the same variety you bought at the supermarket. If you want to experiment without wasting valuable garden space, these are the grocery-store plants worth understanding first.