Answer: hothouses

AnswerCrossword Clue
HOTHOUSESStructures made mainly of glass
HOTHOUSESSuper-growth locales
hothousesA heated building, typically made largely of glass, for rearing plants out of season or in a climate colder than is natural for them
hothousesAn environment that encourages the rapid growth or development of someone or something, esp. in a stifling or intense way
hothousesHOTHOUSE, to rear intensively