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gymnocalycium - failure to thrive?

Posted: Sun Sep 04, 2022 5:16 pm
by CactusCatsCoffee
Hello! I have had this cactus (gymnocalycium horstii?) nearly 30 years and it made pups about 5 years ago. Since then, it has continued to shrivel and the color has been less vibrant with the brown patches. Does anyone have advice?

Re: gymnocalycium - failure to thrive?

Posted: Sun Sep 04, 2022 5:23 pm
by Aiko
Check the roots. See if any are there. And if not, take the plant out of the soil and keep it dry until it starts to grow some roots on its own. Might take a few weeks to a few months (all the way to next sprng). In the mean time keep it warm but out of the most intense sunlight. If it has no roots, it cannot take up moisture, so don't stress it further buy allowing it to continue drying out in a fast rate. Once it starts to show some new root growth, then repot it up in some fresh soil.

If it has roots, repot it too in some fresh soil.

Re: gymnocalycium - failure to thrive?

Posted: Sun Sep 04, 2022 5:52 pm
by CactusCatsCoffee
Ok, so it has maybe one root (on the right). Would you keep it out of soil with this? Should it sit on some pumice or sand or just a flat surface? Is inside ok? What would cause it to have no roots?

Re: gymnocalycium - failure to thrive?

Posted: Sun Sep 04, 2022 5:59 pm
by Aiko
I would clean the plant up (splashing in some water usually cleans it up nicely for my plants). then repot in something more gritty, about 50% topsoil and 50% grit (or maybe better 40%/60% or so).