Question
QUESTION: Hello,  I have had a cactus now for about 5 months or so and it seems to be having some very nice growth.  There looks to be about an inch added in height!  However I have also noticed brown, bark-like spots forming.  I am also noticing the new growth is a lot paler then the old growth.  I am using artificial light (400w Metal Halide).  Is that a result of to much light? I am not to sure what type of cactus I have but I can send you a picture if that helps!  Thank you very much in advance for your help!

Justin

ANSWER: Hello Justin,
Congratulations on your plant. I want to clarify if I'm sure, so can you attach a picture of the brown spots and pale growth? I just want to make sure I won't tell you the wrong answer.

I'm looking forward to your response:)

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Cactus   QUESTION: Hi Joan,

Here is the picture.  I took a few different pictures so if this one doesn't work I can send another.  Sorry for the bad quality.  The only camera I have is on a cell phone.  After seeing the picture would you maybe know what kind of cactus this is?  I might just send in pics of my other two cactus to find out what kind they are too!  

Thanks for your help Joan,

Justin

ANSWER: Hello Justin,
The brown spots are parts of the cactus that have been healed from a damage (such as scratches). Maybe you accidently damaged those parts, but it is also possible that a bug or fungus has attacked it. Look very closely (such as with a magifying glass) to see if there are any bugs or fungus that you might want to get rid of. Regarding the identification, the one with the brown spots is a moon cactus, but I am not sure because it is missing its blooms, which stay almost all year long. The one in the background looks like another 30 species, so I can't be precise. If you have more questions or follow-ups, please ask me and I would be glad to help.

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QUESTION: Hi Joan,

The moon cactus does have a few spots on it where the other stalks (3 stalks total) have actually pierced eachother.  I will watch to make sure that one spot (no idea how I would have done that) doesn't get worse.  If it does begin to get worse do I simply cut it out?  Also, is the pale green growth okay?  It is hard to tell from the pictures but in person it is definelty noticeable.  Maybe this is a result of the lighting?  My watering regime is typically once every 2-3 weeks with boiled water that has sat until it is room temperature.  The cactus is in a 6 inch pot and I typically give it around 400ml.

Thank you so much for the help!  I promise not to bug you to much more!

Justin

Answer
Hello Justin,
If the pale green is only on the new growth, it is totally normal. If there are patches of them around the plant, then there is a concern about the watering. Please let me know:) Regardless of the color, the pierced stalks are the result of the brown spots. If the stalks are 2 separate cactus, you might want to consider "dividing" them into 2 pots. If this is the case, let me know for instructions on dividing cacti. If it is one whole plant (one stalk attached to the other) then you might want to cut the stalk. If this is the case, cut the stalk attached to the base (not the base, or the main stalk!) a couple millimeters apart. Let the cactus heal. You may want to root the new cutting if you would like. Just let the cutting heal completely and insert it into the soil. Then let the soil dry between waterings.

Please don't hesitate to ask me for help!