go to seed vs vegetate

go to seed

verb
  • To pass from flowering or ripening to the formation of seeds. 

  • To deteriorate; to decline into an unkempt or debased condition. 

vegetate

verb
  • To grow or sprout. 

  • To live or spend a period of time in a dull, inactive, unchallenging way. 

  • To spread abnormally. 

How often have the words go to seed and vegetate occurred in a corpus of books? (source: Google Ngram Viewer )