Soil recipe for herbs/Med plants
Good morning folks
I've got a new blockwork planter - I intend to use it 50/50 - one half for herbs, the other for Mediterranean plants. The planter faces South West The inside measurements are 6ft long, 2 feet wide and 3.5 ft deep. I've filled the planter with rubble, soil and perlite so that I am now about 10-12cm from the rim.
I 've read that whereas herbs/med plants both need sharp drainage, they have typically different requirements with regard to nutrients, so I will subtly divide the planter in half.
This is where I'm a bit stuck - obviously I need good drainage but I've never grown these plants before so don't want to go overboard and make it too sharp. I'd add that I live on the West coast of southern Scotland, so typically wet all winter, hence a lot of perlite.
So I'm looking for a good recipe for the top 10cm or so - I've got branded topsoil and compost, along with sharp sand and horticultural grit. From reading about this over the winter I was fairly confident about how to proceed, but then had a brainwave at the garden centre - can I just add a certain type of John Innes eg. to get that ready-made ideal mix?
Any advice is welcome.