Why do tomatoes split their skins when they're growing?

Question

I'm growing some tomatoes and although some are ripening well they've split their skins. What causes this please?

Answer 1

Irregular watering.

Answer 2

Irregular watering.

The insides grew faster then the skins so the skins split.

Answer 3

Lack of water earlier in their growth.

Answer 4

Basically they've had a period where they weren't watered enough and then, when they have been watered, it has caused a sudden spurt of growth which has split the skins.

To stop this happening simply keep watered regularly and use a mulch to help keep the moisture in. I tend to water indoors tomatoes every other day at the start then everyday when they fruit, feeding every few days.