Posted: 15/08/2015 at 06:48
No, temps down to 3 or 4 won't help ripening. That's crazy for August. I've still got overnight temps in the mid-20s though it looks like the daytime temps - which have been in the high-30s for a couple of months - will settle down into the high-20s. This year has been a return to Italian summers of old, last year's was very mild.
I think toms tend to be overwatered everywhere. And over-fertilised too. Pampered, basically. Toms are incredibly sturdy plants that respond best when left to their own devices. Mine, in the ground, are never fertilised more than twice in their lives. Once, a couple of weeks after planting out; once more later in the season.
In fact, this year, they haven't been fertilised at all because I've been busy with other things. The crop has been slightly down but only because the temps up on my terraces, surrounded by dry stone walls, have probably been in the mid-40s. For June and July, when a lot of fruit would usually be setting, it was simply too hot. The flowers were frazzled in the heat before they could do their thing. I took cuttings in anticipation of the heat and planted them out about a fortnight ago. They're growing full steam ahead, plenty of flowers developing, so I should have a decent second crop into autumn.
Your watering regime sounds okay, certainly a lot better than daily watering which is all too common, particularly in milder weather. Deep, infrequent watering sends the roots deeper into the soil. They're likely a bit deeper than the top foot of soil so they're probably happier than you think they are.
They sound like they're happy, though. All you need is some warmth!