Soil/Compost

[spooky1]

Hi
I have built a triangular raised bed size is 2.4x2.4x3.4 it is a split level with half being 24cm and half 36cm high,I intend to make it into a rockery, with alpines.

As you can imagine it would cost a lot of money if I bought the compost from a garden centre, so I thought I would have a go at getting some top soil, sharp sand and some green compost and mix it myself.
Problem is I do not have any idea as to what blend of the components I would need to use and would I need to add anything else to it.

I think I would need in the region of a tonne

I would appreciate any advice you can give.
Many thanks

 

[wrathkeg]

have a look at the 'easy composts' leaflet on here:

http://www.alpinegardensociety.net/publications/Easy-Leaflets/

near the end they give advice specifically about a mix for raised beds. there's also a leaflet on there about constructing raised beds for alpines, but it's a bit late for that now.

 

[roberta1000]

Alpines don't like to be wet and they don't like overfeeding. You don't want much if any compost, green or otherwise.
You need to make sure you've not built a swimming pool so the base needs to be loose and free-draining - maybe spread 4 inches of gravel first and dig it in then fill to the top with a 50:50 mixture of soil and sharp sand. More grit than soil is ideal.