Is it just regular dirt? Some tortoise may eat dirt because they can see traces of minerals in it and feel they have a mineral deficiency, such as calcium. Others do it to try out new things.
If that is the case, we recommend providing cuttle bone (with the hard back scraped off). If your tort is consuming more than a couple bites of dirt, I would not recommend leaving it in that area because large quantities of any substrate (dirt included) can lead to impactation.
Geophagia, the act of eating soil is fairly common phenomenon in many tortoises.
Eating small amounts of sands in Red-foots is quite normal (wild Red-foots in sandy soil often pass feces with up to 70% sand in them). I don’t know the stats on Greeks, but it would not surprise me to find similar numbers.
ALSO SEE: Can Hermann Tortoises eat Diasies?
Can Hermann Tortoises eat Dirt?
Yeah, as far as it doesn’t become an habit, the consumed components are non-toxic and the consumed products can be easily excreted.
So, to avoid any form of impactation, I would use screen sieve to ensure that larger piece of bark, substrate, etc. are not available for consumption.
Otherwise, what goes in, must come out! In other words, good ol’ soil is fine, but no fertilizers (toxins, etc) and nothing too big that could choke or impact your tort’s body system.
What goes in, must come out! In short, good ol’ soil is great, but no toxins (fertilizers, etc) and nothing too big the turt could choke on or get impacted with. Good luck and keep us all apprised.