The problem with the soil here is that the things I have seen adviced in the forum just cant be found here or are ridiculously expensive. Would small stones mixed with the soil work?

The pot has drainage holes. It may seem big but it is shallow(6-7cm).

The plants have stayed on the terrace from the summer and were recently moved in front of a window as it's winter now and it's really cold outside. They were already stretched when my friend bought them.

Would it be alright if she beheads them or it is not their growing season?

Are they over/underwatered and how often and how much should she water them.Its 20 degress in the room.

Vanessa

Is perlite not available in Bulgaria?

There is a pre-made mix available in Europe, under name Lechuza-Pon. I do not know how expensive it is, but check it out. From what I read about it, it is very good mix.

Small stones: how small is small in your opinion? Mixing large particles with small & fine (soil) doesn't really work that well. Size should be something like this:

If you can get also grit, mix them in about 1/3 of each, or 40% of each perlite and grit and 20% of soil.

There is no point to behead plants if the light can't be improved - plants will grow just the same. Could you get some supplemental lights - simple CFL or LED bulbs that are equivalent to at least 100W incandescent will work very well. They should have also high k - marked on the package - I use these (with 6500k):

Container in pic #1 is very low below the bottom of the window - available light is much less by the time it reaches the plant. Raise it up so edge of container is no lower than the windowsill.

Watering depends very much on the potting mix. It will dry up faster in higher temps, but the soil visible in the photos probably take a while, it looks quite water-retaining. So it isn't fair to say how often to water, you need to judge it when soil is just about completely dry.

20 Celsius right? Small, tiny stones, or gravel from outdoors, just wash it through a sieve to remove soil or pollutants. Read some of the other threads here on soil. If you can collect gravel maybe mix it 1/2 and 1/2 with the soil you have. Good growing:-)!!

Can she get aquarium gravel?

Aquarium gravel is pretty expensive and usually coated in epoxy, which makes it fairly useless for holding nutrients. It will hold some water but I still regard it as 'expensive filler'.

If you look hard, you can find uncoated aquarium gravel which is quite coarse on the outside. That would work but is significantly higher cost than something like granite grit (at least here in North America).

There is perlite here but very difficult to find. That's about the size of stones I meant. I checked Lechuza-Pon anf its really expensive. Aquarium gravel is expensive too so I'll find something else.

The plants were already stretched when my friend bought them and they haven't stretched since then so I don't think lights are needed.

The succulents are all in the same pot.

The room is 20 Celsius.

Do the plants look overwatered or underwatered?

Are the plants winter growers and if they aren't will they be able to grow roots if beheaded now or it has to be done in the spring?

theyre etiolated (need more light, gradually) and underwatered.

i never found perlite here (brazil).
People here use gravel on the bottom and mix regular soil (idk how to say it, its just regular dirt i guess) and sand (the kind with big particles)
It works just fine and it's cheap. Some people even use styrofoam! 1-2 cm on the bottom (like gravel) and grated instead of sand.