Brings back memories: when I went to farming school around 1998 - 2000 we once visited a local commercial greenhouse and one thing I remember is they told me t

Brings back memories: when I went to farming school around 1998 - 2000 we once visited a local commercial greenhouse and one thing I remember is they told me they used to have chemicals (plant hormones possibly?) that they sprayed on the leaves of flower plants to stop them from stretching and develop a more compact form, but had stopped doing that and now just lowered the temperature in the room a couple of hours before sunrise to get the same effect.