So today I took up the scissors and attacked our little cherry tomato plants. It looked like a jungle in the grow bed and in the back of my head my father's words rang: 'Light and air they need. They shouldn't touch each other. There has to be room for a breeze between the plants.'
'As soon as you see a little spot on a leave, it has to go. Tomatoes can fade away in just a few hours', he warned me.
I ended up with an entire pile of leaves, it shocked me at first to see how much I had pruned away, but when a visitor gaped at the growbed, saying 'it's beautiful!', I was happy I did it.
We'll see how the tomatoes like their new leave-cut.
For those of you who don't have a father whispering hints about tomatoes in your ear, there's a nice WikiHow about pruning tomatoes: http://www.wikihow.com/Prune-Tomatoes