In addition, application of PGRs is time-consuming.
In northern areas temperature drop treatments in the morning are commonly used in combination with PGRs to reduce elongation growth.
However, use of such temperature drops is limited by periods of high temperatures and high solar radiation in early autumn as well as energy-saving regimes in semi-closed or closed greenhouses.
As an alternative, exploiting the responses of the plants to different light qualities provides an interesting possibility in greenhouse production of poinsettia