Ok, thanks for the tip Yvonne G. I'll try it out this weekend. And Tom, it is not very easy for me as the tort can dig under it and I am not really and expert in this.
Had my young russian lost in my grandma's garden. She's like 7 years old and we take her every summer to my grandma's garden. Sometimes she gets lost, but we find her all the time. However it's been like 4 weeks, and we haven't found her directly. During summer she always hibernates, so we are...