Why do my tomatoes, in the greenhouse, grow like the clappers but do not produce flowers until high up on the plant. Even my Sungold is to the roof before the 4th truss. I grow in bottomless pots in a mix of compost, peat and perlite and wonder if I am providing too much nitrogren and if so, how do I prevent this. Also my preferred toms tend to be the open pollinated (heritage?) ones so would that affect them? One further question any recommendations for outdoor tomatoes please.