Catfacing can be related to conditions: for example, too much nitrogen, inconsistent soil moisture, cold temps while blossoms are forming, or exposure to pesticides.

But as catfacing is more common in beefsteaks, there is probably a genetic factor. [IIRC, some varieties are more susceptible to catfacing, too.]

Can it be prevented? Only to the degree that you can control the contributing factors listed. That and grow resistant varieties.

IMO some is expected when growing tomatoes given we can't control the spring weather so I don't worry about it. If it persists further into the growing season then it's time to fix whatever I am screwing up - most likely inconsistent soil moisture levels.

Dave

Similar causes as to blossom end rot. Make sure there is lots of organic material in your soil to buffer the moisture level.

I've noticed some of the smaller 4-8 ounce varieties are said to be more resistant.

Examples....

Thessaloniki
Eva Purple Ball

thisisme:

I have never had a significant "Catfacing" problem with a round tomato. But some beefsteak or severely oblate tomatoes seem to "catface" no matter the weather, or how they are grown.

I have quit growing some varieties because they always do, and are not exceptionally outstanding, but have grown a few for years that are always lumpy, but taste so good I am willing to chop them up rather than slicing them, just because they taste so good.

Thank you for the replies.
I suspect cool night time temps during blossoming
And inconsistent soil moisture
were the culprits in this instance.

I will try to be more careful with watering this year,
Not much I can do about temps, though.
And no pesticides were used.
I doubt that there was too much nitrogen,
But I guess there could have been.
We'll see how it goes this year.

Again, thank you.

Rusty