cultivate vs greenhouse

cultivate

verb
  • To nurture; to foster; to tend. 

  • To turn or stir soil in preparation for planting. 

  • To grow plants, notably crops. 

greenhouse

verb
  • To nurture in order to promote growth. 

  • To place (plants) in a greenhouse. 

noun
  • A building used to grow plants, particularly one with large glass windows or plastic sheeting to trap heat from sunlight even in intemperate seasons or climates. 

  • A hot state in global climate. 

  • A structure that shields the operating table to protect against bacteria. 

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