Bob,

Too much water and variety of the plant leads to cracking the skin open. I believe there are other reasons that I don't recall right now. Others could help.

If you are watering every day, you are flooding the root zone, especially in the PNW. Are you sure you are in zone 5?
Stop watering until you can push your finger down in the soil without it feeling moist.

I have yet to use the drip irrigation system installed this spring. Amazing considering the heat we have experienced here in the Heartland.

Tom

He's in SE WA on the Columbia River Plateau, which is arid grassland and steppes. Hardly any rain out there during the summer.

I had a hose burst about a month ago that caused a flood near my tomatoes and consequently I've got a few that are ripening now that are cracked. Since then I've been careful to only water every other day, sometimes even longer.

I'm actually located in the Pullman area. I always thought that the tomatoes would crack if they were dry for a period of time and then received water. It didn't occur to me that they may be getting too much water.

Bob