Posted: 25/08/2013 at 15:48
David, a couple of things. If they're in a greenhouse, you probably need to give them a hand with pollination. Toms are self-pollinating but the pollination process is helped along outdoors by insects and even the breeze. Any movement of the flowers can help trigger the internal mechanics that bring about pollination. Indoors, you can help out by giving the flowers a gentle flick with your fingers.
I think you're also overfeeding them. Toms aren't big feeders and will produce better if left more to their own devices. Toms exist to reproduce themselves - by producing fruit - and they're more likely to feel the need to reproduce if they feel a bit threatened. Cut back on the watering and stop feeding them. See what happens.