Frost is awfully hard to cope with at high altitude. There are ways farmers can hold onto some of their important frost sensitive plants.
Newspaper and better still cardboard acts as an insulator. It is more effective than dry grass mulch. However, putting the newspaper on, then adding dry grass on top will be helpful.
A large church tarpaulin (sel) can be spread over quite a few mounds. So long as this is done in the early evening as it gets really cold, this will help to keep frost away.
There’s more tips in the manual that is being written.