A hole in one...

[rodsmith]

...of my cacti! This split appeared in my Turbinicarpus schmiedickeanus var. polaskii about 3 months ago, although it may have been there earlier without my noticing - hard to miss an enormous split in a small cactus, you may think. I don't know what caused it but I suspect it was over exuberant watering on my part early in the season. Despite the damage, which has completely calloused over, the plant continues to produce flowers regularly and is now showing signs of putting out an offset from the top of the plant. The plant has grown quite a lot since I noticed the damage and the split is much less noticeable now. When I first noticed it, the damaged area was about a third the size of the plant, now it is well under a fifth. I took these two photos today.

Turbinicarpus schmiedickeanus var. polaskii

Turbinicarpus schmiedickeanus var. polaskii

[ragamala]

My first thought was mouse.... or bird maybe...

[DaveW]

I had one or two split this year and of all things a Selenicereus which split about 6 inches along the 3/4 inch diameter stems. I have never had Cerei split before. Whilst unsightly it never seems to kill the plant which continues to grow quite happily.

With plants like your Turbinicarpus the split eventually finishes down at the base in time and disappears.

As Ragamala says, that looks more like a hole than a split though.

[Keith H]

My small Turbs are all looking a bit bloated this year despite me trying to hold back a bit on their water, fortunately I have not managed to split any of them.
I found it was the large Gymnos that seem to split very easily three years ago though it was their first growing season back in my care so I think I was pushing them a bit too much.
As others have said they will grow out eventually in the mean time enjoy the flowers.

[Peter]

That looks like slug damage, Rod. Time for the blue pellets in a dish.

[Chris in Leeds]

Yes I agree with Peter it doesn't look like a split with the shape of it and the edge makes me think slug

[rodsmith]

Thanks all for your thoughts. I hadn't considered a slug as a possible cause. I overwintered a couple of outdoor plants in pots in the conservatory with the cacti and a slug could well have come from one of them. I haven't noticed any other damage but will do as suggested and put down some little blue pellets.