Succulent mix for a larger garden bed

Hi. I am very very VERY new to cacti and succulents.

I am building a garden for succulents which will occupy about two-thirds of a court yard which measures 9m x 4m. The entire area has a crushed rock base so should drain ok.

I have been researching a suitable sand/soil mix for the bed. Everyone talks about a pre-mixed cacti mix - particularly for potting. I have already brought in 1 cubic metre of washed river sand (will not compact) but am looking for something to add nutrient to the bed. Obviously bags and bags of cacti-mix is too expensive for this exercise. The existing sand (1 cubic metre) is about half the volume of the anticipated final mix.

Any suggestions what I can mix in (cheaply)? I was thinking 1 cubic metre of mushroom compost. And should I mix thouroughly or leave on top of the sand? I plan to mulch the bed with river rocks / pebbles of varying sizes. Any other suggestions?

First of all. Welcome to the ACF candyman.

Cacti or succulents? Or both.

I would recommend perhaps topsoil mixed with the washed river sand and alot of serious cacti ground gardeners reccomend composted cow manure. Scoria might be a nice addition to the actual soil too, depends on what you want to grow. As long as there is adequate drainage there shouldn't be a problem.

See what others have to say. I haven't got many in the ground at this point.

I have a feeling CP might have some experience with this and some good information about soils.

Thanks Trigonus. I plan to plant both (cacti and succulents).

Hey Candyman, welcome to AFC.

I agree with Trigonus in that it completely depends on what your growing.
As a rule of thumb, I would make the soil more organic for succulents and less for cacti. This is generally speaking though.

In terms of what to put in there, as far as cacti goes Trichocereus might be good because they are fairly tough for a lot of different conditions.
These are a column type of cactus that grow pretty fast and are easy to grow.
They are also more likely offset (branch) from the base being in the ground which would look beautiful in a few of years.

Just a suggestion.

Thanks KanJe. I have proceeded with about 10cm washed river sand and topped with a 10cm deep 50/50 mix of washed river sand and mushroom compost. On top of that I have shovelled a layer of 50mm - 150mm river pebbles (I now remember why I do not like shovelling rock).

When I plant each succulent or cacti I will use an appropriate potting / cacti mix for the planting hole.