Posted: 04/05/2013 at 19:36
To pIant out dahlias, I would wait until the night temp is consistently around 8-10c. Then it is safe. Yes - pinch out the tops of dahlias when they are about 9" high. This strengthens the main stem and helps with stabilizing the plant in windy conditions, as well as supporting large flowers. It also provides more stems with more flowers!