So when you're trying to figure out what the best diet would be for your land turtle or tortoise, it's always a good idea to take a look at what their natural environment is like and to read about the sorts of things they consume in that environment. Some of our tortoises and turtles that come from dry, more arid climates in their natural environment they would be eating leaves and grasses and flowers. So they require a high fiber, high calcium, and low protein diet.
In captivity, we do rely on store-bought vegetables, but it's also good to feed these types of turtles and tortoises different types of hay and dried grasses. When you're purchasing store-bought vegetables for your land tortoise, again, you want to look more towards the darker, leafy green vegetables as opposed to lettuces. Some good examples of some dark, leafy green vegetables that you can feed to tortoises would be things like kale, collard greens, and mustard greens.
Some of the forest-dwelling species and the more tropical or subtropical species of land tortoises and turtles, you want to be including perhaps a more high protein diet and fruit. So again, there is no easy answer to what to feed your land turtle. It depends very much on their natural environment and their species. So do your homework before you decide what to feed your land turtle.