First lean-to was in 1710 at the Leyden Botanic Garden. In U.S. by 1758 greenhouses not uncommon. First recorded greenhouse in New York City was Beckmans in 1764. By end of 18 th century, cast and wrought iron brought improvements and ornamentation. Big glass-making jump by French and imported into Britain by Chance Bros of Birmingham in 1832.
Cost goes down.
19 th century design enhanced first by Mackenzie's studies of light transmission in 1815 and next by the structural technology developed by Loudon and Paxton. By 1800 American horticulture had begun to mature. Playground for the rich and famous. Science and education also pushed greenhouse development in the 1800's - botanic gardens at the forefront for study of tropicals. Palm house at Kew 1848.