Yes, you can feed your tortoise those greens for a treat. They also love bok choy, watermelon, and cilantro. But your tortoises main diet should be Hay or grass from grazing. If feeding them greens for long periods of time, make sure you put on the calci powder with vitamin d3, and mineral powder. Most the tortises fiber comes from grass and hay. Alfalfa hay , timothy hay and bermuda grass are also good.