hothouse vs summer house

hothouse

noun
  • An environment in which growth or development is encouraged naturally or artificially; a hotbed. 

  • A heated greenhouse. 

  • A heated room for drying greenware. 

  • A hot state in global climate. 

verb
  • To provide (a child) with an enriched environment with the aim of stimulating academic development. 

summer house

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