Cacti turning brownish. Over/under watered or sick??

[emmanic]

I have a austrocylindropuntia subulata monstrous (I think) in a terrarium with a few other plants. I'm new to looking after plants so don't really know what I'm doing yet.

Many of the off shoots (leaves possibly? I don't know) have lost their fullness. They are less turgid and thick than they were before and some are curling round on themselves. Some have also gone brown (I know that this plant may sometimes go a reddish colour but I don't think this is the same).

I don't know if this is to do with my watering habits as my other plants in the terrarium seem okay, or if they are maybe sick.

Can someone please advise?
Sorry photo isn't great but I hope it shows what I mean better than I can explain it.

Thanks in advance.

[iaeen]

In general, terrariums are not good places to keep cacti or succulents. These plants require fairly dry conditions and good air movement, both of which are difficult in an enclosed environment like a terrarium. Also, terrariums generally don't take into account different requirements of different plants when they are put together.

The best thing you can do here would be to plant all these plants in individual pots using a well draining soil mix containing mostly minerals like pumice. Read some of the articles on this website, and you will have the knowledge to move in the right direction.

[SoilSifter]

The leaves on your Austrocylindropuntia are dieing because the plant is becoming dormant. I'm not sure if this cactus normally becomes dormant at this time of the year or if you give it the right conditions it won't become dormant. I have an Austrocylindropuntia subulata. It likes a lot of sunlight. It seems to like a bit more water than the typical desert cactus. However, mine often has a mix of dormant and actively growing branches. When mine becomes dormant the leaves die. Also, I noticed the new growth is skinny at the tips of your plant's branches. That means your plant needs more light.

[CactusMad]

I totaly agree with Iaeen,the plants needs taking out of the terrarium,because these kinds of plants do not like humidity,they like dry,bright conditions.They need more light and seperate pots with a good well draining mix in.

[iann]

Not a problem. The leaves are temporary - they grow when times are good then get absorbed later. It probably does need more light though.