You talking about the fruit or the stem of the plant?

If the fruit, did it rain recently? A sudden growth spurt following a rain storm or heavy watering after a dry spell will cause the fruit to split. Even and deep watering will help reduce that. Mulch around the plant too. Water an area 2-4ft away from the stem, if the plant is mature.

Too much water + heat = splittage of the tomaters.

I get that on a few tomatoes every year because it gets so hot during the day. You can't save em all! (Unless there's some trick that I am unaware of...)

It's the fruit, and it sounds like we had the perfect combination of the conditions described. We had a ton of rain last weekend - two solid days of ark-like flooding. And this week it started getting into the 80's during the day. Thanks for the info.

Rachel

Here is a link that might be useful: LookMaNoWeeds