Hello,
I am a novice cactus enthusiast and so any help would be greatly appreciated please!
I was gifted a lovely terrarium - a big glass bottle (turned on its side) with several small cacti.
I have noticed that a couple of these cacti have suddenly turned white on one side. The only change I have made is moving them to a window with more sunlight exposure. I don't know if this could therefore be some kind of sunburn, perhaps?
What do I need to do to allow them to turn green again?
Also, watering it a bit tricky as there are only 2 small holes through which I can access the inside of the glass, which makes it difficult to water the base of the cacti. So how would be best to water and do I need to slightly under-water them as this is a closed system (i.e. has no holes for drainage), or will the stones act to mop up excess water and stop it rotting the cacti roots?
I would appreciate any help!
Many thanks

Severe sunburn..
Why are they under glass?

I think it's sunburn - but it's weird to me that cacti were in your gifted terrarium. They are not a plant I associate with the growing conditions inherent to a terrarium. So many cacti grow naturally in hot, dry climates for at least part of the time and terrariums that I've seen have plants adapted to warm, moist - and generally continually moist - conditions which would be a death sentence for many cacti. I can't identify your particular cacti, but they don't appear to be the sort which would naturally thrive on the floor of a tropical jungle - conditions found in a terrarium. Just my thoughts. If those were Gesneriads of some sort instead of cacti it would make more sense to me.

So this is an image of the "glass bottle lying on its side" .
So if this is not an appropriate environment for my cacti, what is the best thing that I can do?

Buy new plants and grow em in pots...

All of your cacti are dying and unfortunately the common denominator is that bottle. Like others have mentioned, that is sunburn, and very severe on a few of them such that the amount of bleaching might kill the plant. I'd take your plants out and put them in proper well draining nursery pots to try to recover with only indirect sunlight and a good soak with water.

meganrb17 said:So this is an image of the "glass bottle lying on its side" .
So if this is not an appropriate environment for my cacti, what is the best thing that I can do?

Wow! What a nice collection were put in the bottle! I believe I recognize one of them . And it would not be amenable to the growing conditions in a terrarium. I only see two plants with a lot of sunburn. Personally, I think they both might recover and grow well given time and a good environment.

For starting, if that were mine, I'd remove all of them and just lay them down on a paper plate or something out of direct sunlight and let them dry for a few days and look for any rot they may have before I put them each in their own small container. Containers with drain holes (essential for these type plants) and fast draining potting medium. After that, if there was no rot evident, I'd wait a couple of days before giving them water. Everything I see there will want a lot of sunlight. I suspect the bottle acted somewhat like a magnifying glass causing them to burn more than they would have if they had been out of it. I would move them into more and more light until after a week or two they were getting six or more hours a day of sun. That's based on outdoor conditions. I don't really keep mine inside, but if the sunlight were coming through a window I'd expose them to the light a lot quicker. I haven't found many plants burn when the sun enters through a window, but window conditions often don't let a plant get a sufficient amount of sun. Guess it all depends on your particular situation.

Personally, I'd try removing them, checking for rot, and repotting them in a well draining soil and see if some of them recover.
It's unfortunate... It's definitely a nice collection of cactuses you have there, but a terrarium environment isn't the best for them. High risks of sunburn, humidity climbing too high from lack of ventilation, and no drainage risking rot.

If you're able to get them out of there, best of luck!
You might be able to use the bottle for some small tropical plants that like a more humid environment.

I think this may be one of the rare cases where indoor cacti get sunburned because there is a lensing effect with glass between them and the sun. Normally it's really hard to sunburn indoor cacti, and it should be impossible if they are well grown to start with. I agree, get them out of the bottle, find pots with holes, repot, and wait at least a week to water for the first time.

Whoever put together that arrangement did not expect or plan for the plants to survive long term there. Some people treat succulents like cut flowers, as something to harvest and arrange and then dispose of when they inevitably wilt and die.

It sounds like the best way forward will be for me to try and remove them from this bottle and pot them individually. Hopefully I'm not too late and that they will be much happier like this, in more appropriate conditions :cross_finger:

I can't thank you all enough for your expert knowledge and advice!

Now..... just the tricky job of working out how I'm going to get them out of that glass bottle Any suggestions welcome

meganrb17 said:So this is an image of the "glass bottle lying on its side" .
So if this is not an appropriate environment for my cacti, what is the best thing that I can do?

Hmm, I've planted succulents in glass bottles before and never had any trouble. Maybe the damage is specific to cacti?

How long have they been in the bottle, Kim?

meganrb17 said:It sounds like the best way forward will be for me to try and remove them from this bottle and pot them individually. Hopefully I'm not too late and that they will be much happier like this, in more appropriate conditions :cross_finger:

I can't thank you all enough for your expert knowledge and advice!

Now..... just the tricky job of working out how I'm going to get them out of that glass bottle Any suggestions welcome

Long tongs and sturdy gloves!

Might be tricky, but you could probably grab them with tongs, gently wiggle them out of place and work them through the holes.

The soil doesn't look to deep. I think tongs with small grabbers and something like a long wooden spoon. The spoon could be used to loosen the soil around/underneath the plants nearest that hole before they are tonged out. Then it could be used to slide the whole mass of rocks and soil from the neck end toward the hole and work them out as they come into position. Hopefully, the one on the far right will slide to be more in front of the hole when others are out of the way. They went in, so they can come out. A long piece of bamboo might work in lieu of the spoon. I just like the idea of the spoon end and I use one here to cook with that's very small on the on the spoon end; others I have would be too wide I think. Alternatively, if worse comes to worst, you might try shaking them out (as gently as possible) like pennies from a piggy bank. All the above is assuming you don't want to bust the glass to extract the plants.

Excellent advice from everyone here
all I can add is good luck and come back and update us after it's done . It's such a shame when sellers basically set people up to fail from the start
Steve

Tongs and a wooden spoon sound like a sensible idea.
It's such a shame that I have to remove them since it is a nice display unit. However, thanks to all of you, I now realise that this is not an appropriate environment in which to keep them. So fingers crossed that I will be able to get them out and hopefully save them!
I know where it was bought from and it is a huge, highly reputable garden centre. Which just makes you wonder if they assembled this display, or bought it from somewhere else? Either way, I do feel genuinely disappointed that they would have created this, knowing that the plants would not thrive (or even survive for very long) in this inappropriate environment.
I may post some photos of the plants once I have "dug them up" in case there is any evidence of ill health, such as root rot, which I would need to do something about, as I would appreciate your expert advice once again please! So if anyone wouldn't mind checking back to look at some more photos, then I would appreciate that for a bit of further help please.
I am truly grateful to you all for helping me.
Now let's hope that I can get them out successfully to try and save them

This bottle is a nice display unit.
I have seen some nice terrariums with Haworthias in them.
Haworthias like to be dry so you do not have to water them often.
They have shallow roots so they do not need deep soil.
They are slow growers and make wonderful indoor plants.
That large round hole in the side looks like it can be used to replant your new garden.
Does your hand fit through the opening?
You can use tongs to move the plants around.

Thank you for the suggestion about Haworthias - I will definitely look into this as it does sound like a good option.
My hand does fit through the hole, so I'd hope I would be able to successfully plant some small succulents or such. I would just need to be careful not to choose succulents with long flower stems.

So, I have managed to successfully extract all the 9 cacti.
The soil is very moist and so a lot has fallen from the root balls without me doing it.
I have left them on a tray to dry a bit before I am planning to pot them individually using appropriate compost and in a snugly fit pot with drainage.
If there is any which anyone thinks could benefit from further care then I would appreciate all suggestions.
I have taken photos of each of them so that you can see how healthy / damage caused.
Many thanks for taking the time to help me.