put out to grass vs put out to pasture

put out to grass

verb
  • Synonym of put out to pasture 

put out to pasture

verb
  • Used other than figuratively or idiomatically: see put out, to, pasture. 

  • To make someone retire, especially due to advancing age. 

  • To discontinue something. 

How often have the words put out to grass and put out to pasture occurred in a corpus of books? (source: Google Ngram Viewer )