earth up vs grass

earth up

verb
  • To cover the stem or leaves of plants with soil, as to encourage root growth or protect from cold. 

grass

verb
  • To expose, as flax, on the grass for bleaching, etc. 

  • To bring to the grass or ground; to land. 

  • To feed with grass. 

  • To act as a grass or informer, to betray; to report on (criminals etc) to the authorities. 

  • To lay out on the grass; to knock down (an opponent etc.). 

  • To cover with grass or with turf. 

noun
  • Asparagus; "sparrowgrass". 

  • Marijuana. 

  • Sharp, closely spaced discontinuities in the trace of a cathode-ray tube, produced by random interference. 

  • The season of fresh grass; spring or summer. 

  • An informer, police informer; one who betrays a group (of criminals, etc) to the authorities. 

  • The surface of a mine. 

  • A lawn. 

  • Various plants not in family Poaceae that resemble grasses. 

  • Noise on an A-scope or similar type of radar display. 

  • Any plant of the family Poaceae, characterized by leaves that arise from nodes in the stem and leaf bases that wrap around the stem, especially those grown as ground cover rather than for grain. 

How often have the words earth up and grass occurred in a corpus of books? (source: Google Ngram Viewer )