Can you identify the problem with our cactus and what can be done? Thank you....

Asked September 11, 2014, 5:35 PM EDT

Can you identify the problem with our cactus and what can be done? Thank you. - Barbara Details: - 31 years old (indoor plant) - plant started getting "corky" several years ago but that didn't change the condition of the arms - 45 inches tall - lower arms started getting lighter green about 6 months ago - plant was repotted (1st time) about 3 months ago in a pot of similar size but alone (had been with other succulents) in cactus soil with good drainage and moved from fairly bright sun to part shade (from partially open blinds); both locations near a west-facing window - about 1 month after repotting started using Miracle Grow for cactus (10 drops to 2 cups, as recommended on bottle) and have been watering once/week - result: lower arms got even lighter - more yellow, while top is growing quickly, getting new "leaves" and is good dark green - A few days ago, moved it next to a south window for more light. Plan to water less frequently and without miracle grow unless you suggest otherwise - Notes: I closed the blinds so the picture is easier to see (i.e. not the way they are normally facing); I can send a 2nd picture that shows how healthy the top of the cactus is, if that would help

Montgomery County Maryland

1 Response


Cactus and many other plants just get woodier (corky) with age. There is not much you can do about that. Most cactus require very little fertilizer, I would only give them a dilute fertilization (1/2 strength) maybe 2 or 3 times a year during periods of active growth. As the tissues age, they become less photosynthetically efficient and the plant will direct its resources (like nitrogen which gives leaves a nice green color) to new growth for which it will get more bang for the buck so to speak. It sounds like your plant is simply aging. Many people do not like the way older plants get and start new ones from cuttings. You might want to check with your local Master Gardener about more tips for taking care of your cactus or to learn how to propagate it.