Sod layers are people who install or maintain sod, which is a layer of established grass that is dug up with roots and some soil still attached1. Sod is used to create or renovate lawns quickly and effectively1.
The author of the puzzle chose this answer because it is a pun, which is a form of wordplay that exploits multiple meanings of a term or a similar-sounding word for humorous or rhetorical effect. In this case, the phrase “a lot of ground to cover” can mean both having a large area of land to work on and having many topics to discuss. The pun creates a contrast between the literal and figurative meanings of the phrase, making it amusing for the solver. Puns are often used in cryptoquip puzzles to make them more challenging and entertaining