The pads (?) on our crested coral cactus are drying out and becoming wooden. We've had the plant for around 25 years, it's lived in mostly the same place and received the same care over those years. This began 6 months ago at the tips of the branches and is slowly progressing toward their bases. It's been repotted once and probably needs a change again. It's in a SW facing window where it gets monthly waterings in the winter and biweekly water in summer. We use a cactus supplement on the watering.

Is this old-age or could it be a pest? (There's a desert rose/adenium obesum next to it that has a never-ending side mite infestation that we treat with Neem oil but there are no signs of the mites on the cactus.) Or, is it time for a change in care?

Thanks.

Don

That's a beautiful plant.

Even though everything has stayed the same, obviously something has changed. The easiest thing to check is how well the soil is hydrating. Water as you normally do. Does the water run through quickly? Can you dig your finger down into the soil and feel moisture? Use a bamboo skewer to check for moisture content at the bottom of the pot. Shove it down to the bottom of the pot, leave for a couple minutes and pull it out. Is it wet or dry? If you can't see or feel moisture, the soil has become hydrophobic.

There are two ways to try to solve that problem, water multiple times a few minutes apart until the soil rehydrates or soak the pot in water up to its rim until the soil rehydrates.

Thanks for your reply. The soil is definitely dry. I'll take your suggestion shirt green but it sounds like the smart move is to repot the plant to give it some fresh soil and breathing room. Much easier than dealing with a pest.

I saw a video last night and the succulent expert said at times repotting is indeed needed, at a certain point the media loses its buffer..so a decline in the growth of the succulent happens.

He was also mentioning about the ph of the water being used..maybe that affects it too.

You may want to see the video..it is quite informative. It was a video about watering the succulents, overall care and the discussion is quite educational. Maybe it will help you understand what happened to your plant.
https://youtu.be/P26p2cBl6ZY

I wouldn't repot now. Its the wrong time of year. If the soil is dry, water then check to make sure the soil absorbed the water. It doesn't have any pests.

DaisyI said: I wouldn't repot now. Its the wrong time of year. If the soil is dry, water then check to make sure the soil absorbed the water. It doesn't have any pests.

That makes sense. I do plan on following your advice about rehydrating the soil in the interim.

tarev said: . . . You may want to see the video..it is quite informative. It was a video about watering the succulents, overall care and the discussion is quite educational. Maybe it will help you understand what happened to your plant.
https://youtu.be/P26p2cBl6ZY

Thanks. Not sure whether I was more taken with the advise or the plants.

Indeed! So much plants in that video..

Euphorbias are not a cactus, they LOVE water.
I agree with Daisy. You need to hydrate this plant.
The 'paddle' growths look a little thin to me.
My E. lactea "Coral Cactus" are much plumper.
Of course my growing season is all year long and
my humidity is higher than yours, which probably
is why my plants are plumper.
I also agree with Daisy that winter time is a bad time for
repoting. It is better to wait for new growth.
Are the brown parts crispy?
They look dead to me. You may want to cut them away from the healthy plant. This brown may want spread.
If the brown parts are soft and squishy it might be rot.
It doesn't look like sunburn but it might be freezer burn.
Too many possibilities.
Is it soft or hard?

Thanks for the clarifications.

The brown areas are dry. They can be broken off or cut. I soaked the soil as Daisy suggested and will monitor it. When you say the euphorbias love water does that mean the soil should not dry out? Or, should it dry and then be watered to moistness again? (By moistness, I mean Daisy's bamboo skewer approach. Or, if the soil holds water once again is it enough to feel the soil surface for moistness?)

Most all cactus and many succulents prefer to dry out before their next watering. In my experience this is not true for Euphorbias, Aloes and Agaves. These three genera survive in Hawaii landscaping where it never dries out. Good drainage is important.
Dry brown parts is better than squishy. No diseases.
They just died from lack of water.

OrchidBob, what's this thing you call "humidity"?

Thanks for your help.

My Euphorbias love water IF the temps outdoors is hovering in the 85F and higher range. But if it is cold at 50F and lower...best to keep them dry, and if one can, hide them indoors till better temps return. Just keeping them warm and in a bright light area will do.

And yes, at all times, always in gritty, well-draining media. If I do water them while indoors, I only do it very, very lightly, and at most once a month during winter while indoors.

Some succulents just go very dormant in winter..so keeping them dry and warm is the best option for them. May make them thin but they will eventually bounce back once their preferred temperature and light levels returns.