Growers need to work out different production schedules for different varieties of Poinsettias according their relative vigour and not just according to their response time. A variety such as ‘Peterstar Red’ for example is very vigorous. The date of pinching and the length of the subsequent vegetative growth period affects plant height.  US trials compared plant growth under different regimes. One group of plants was pinched 2 weeks after planting, then given 3,4 or 5 weeks of long days before short day treatment. The only difference in the second group was that the pinching took place 3 weeks after planting. According to the same researchers, Poinsettias grown in the US in 2001 tended to be shorter than normal. This is thought to be due to brighter warmer weather, more growth regulator application on the young cuttings by propagators, lack of experience with new cultivars, less DIF due to the warmer weather and higher fertility due to increased irrigation. P.Allen Hammer, GrowerTalks  www.growertalks.com