Good desert grass to grow for tortoise enclosure?

I am looking to add a little vegetation into my Russian tortoise's enclosure. What edible plants grow well in very sandy, mostly dry soil? I am looking for something hardy to supplement his diet.

My substrate is play sand and Ecoearth, can add a bit of something else if needed, but, would really like a desert type plant that prefers sand and arid environment.

Most grasses/legumes I know of will need a lot more care and attention- as well as avoid very sandy soils.

Thanks!