What are these lines?

[RickNC]

These beefsteaks keep ending up with these lines on top of the fruit. They also get one crack in them as they ripen. I have grape tomatoes next to them and they are doing fantastic.

[img]https://i13.photobucket.com/albums/a279/RTrone/P7080237.jpg[/img]

[TZ -OH6]

That is called concentric cracking. Some varieties are geneticly predisposed to do it. Its an "ugly heirlom" trait and usually doesn't hurt anything. It doesn't mean you are doing anything wrong....also, some varieties develop deep cracks radiating out from the stem (radial cracking). Both of these are different from water conditions splitting the fruit.

[RickNC]

Thanks. I have two of these plants and it happens to both of them. The grape tomatoes are absolutely perfect with tons of fruit. Still waiting on my two heirlooms to produce ripe fruit. So far they are still green.

[rainbowgardener]

the bigger the fruit the easier it is for it to crack and the slower it is to ripen....