Well that makes sense, due to the pot being full coco and perlite. Throughout summer I would let it dry out for 3 days then fully soak it. However we did have extremely hot weather which made it dry out in half a day. And then we had 1 week of rain.Splitting and cracking is caused by too much moisture in the soil and the tomato absorbing water faster than its skin can grow. This mostly happens when a gardener grows his tomatoes in drier than optimum conditions and a big rain comes or he forget to turn off the water hose.
I was giving it 1.5litrw every 3 days at first, but as it got bigger and I noticed the sun drying the pot out, that turned to 1.5 litres per day, it was still drying out by say 3pm. So that turned to 1.5 litre twice a day. Since the extreme heat has gone I give it 1.5 litre per day now. But maybee that's too much then, I really don't know. I give it tomato plant food twice a week aswell.
The plant has never really shown signs of underwater or overwater. It did start dieing at first that's when I started watering more regularly. None of the new tomatoes have splits or anything but there still small. I will have to take some proper pics and show you guys.