Composting works by mixing organic material with water, oxygen and time until you get a rich fertilizer. But, the process only works with the right proportions of “greens” and “browns.” Every material has its own chemical profile, but generally: greens, like veggie scraps, contain more nitrogen and browns, like dried leaves, contain more carbon. (To nerd out more, start here.)

In your kitchen, you’ll mostly collect greens. With that in mind, here’s a handy set of do’s and don’t’s to reference when you find yourself asking, “Can I compost this?” Every Soil Cycler will get one of these cards to stick on their fridge, but if you lose yours or just want another for posterity, here’s a spare you can print out.