Perhaps E. echinus...

I'm interested in knowing how to differentiate them as well but something tells me it isn't possible.. at least not with the naked eye. Since spiders from what I know are beneficial insects, it probably is best to leave them alone, unlike spider mites.

When your Opuntia starts resembling a Selenicereus..

Agree with Frailea for number 2. Rebutia generally flowers from the base while Frailea from the apex.

It depends on the climate wherever you're at so it always helps to include your geographical location to ensure relevant cultivation advice. During the growing season I would water at least once a week, assuming the "cacti-friendly" soil is indeed cacti-friendly. The safest method is to wa...

The cactus you have is either a Stenocereus pruinosus or Polaskia chichipe. As the name suggests, the pruinose (powdery white) surface is completely normal. See: http://www.cactus-art.biz/note-book/Dictionary/Dictionary_P/dictionary_pruina_pruinose.htm. The same goes for the succulent in the other p...

A similar thing happened to my P. lamerei which is considerably larger (about 30cm tall). It seems that mine had a fungal attack due to sudden exposure to rain after being indoor for a long time. I gave it some anti-fungal meds and the black spots on the leaves stopped after a few weeks of treatmen...

A similar thing happened to my P. lamerei which is considerably larger (about 30cm tall). It seems that mine had a fungal attack due to sudden exposure to rain after being indoor for a long time. I gave it some anti-fungal meds and the black spots on the leaves stopped after a few weeks of treatment...

First one could be Opuntia rufida. Regarding watering, I would err on the side of overwatering since from my personal experience these mini Opuntias thrive in richer and wetter soil than do other cacti. Of course everything would depend again on the conditions (e.g. soil mix) you're growing them in.

Thank you for your comments, Harald. I am not convinced yet that it is sunburn since it was not under full sun when the black spot appeared. Could it be fungus? It might be difficult to get a closer photo to ascertain that considering the length of the spines.

Mean daily minimum temp: 24C Mean daily maximum temp: 33C We only have wet (November - April) and dry season (May - October) here so the temperature remains quite stable throughout the year. Mean total rainfall: 1655mm Lowest: September 29mm Highest: January 385mm Elevation: 15m Outside on balcony D...

This probably does not look good and may be indicative of rot. But from what I know rot usually starts at the root area and feels mushy - this does not. I bought this a month or two ago and the rest of the plants it came with had no issues at all. Could it be signs of growth of a new cladode? Or lac...

Hey there good people, At the moment my cacti are outside with my succulents resting in a plastic shelve in my balcony, thing is, when it starts raining, they all get wet and I'm afraid they will rot, I was thinking in buying a tarp, making some holes for ventilation and with some velcro strap do l...

First one is most certainly a mealybug. Second one is like you mentioned where an offset (or "baby") used to be.

I thought I'd share my experience rooting a rot-prone species here for the benefit of others looking to do the same. So I bought a rooted cutting of E. grandis and true to its reputation when it arrived there was what I suspected to be rot - soft and mushy - at the root area (the dark patch visible ...