What do I do with old plant roots?

[BusyBee]

I know this sound like a silly question, but I'm new to gardening and my only sources of information are online. What do you do with the roots of old plants like herbs and veggies? I recently grew cress and and have some other herbs that have wilted, and I'm not sure if I should be composting the roots or doing something else?

 

[Marck]

Composting them would be fine.