In article , WaltA
writes

a brief google, I was sure, would lead me to the John Innes Institute
where all would be revealed ! Sadly no
So perhaps I've been under a delusion these past few decades

If you need to follow the DIY route then we could exchange emails and
I'll send you the info that I have in my library !



I have it in my The New Small Garden by Lucas-Phillips circa 1979!
Seed compost
2 parts by bulk sterilised loam
1 part by bulk peat (moss or sedge)
1 part by bulk sharp lime free sand

To these are added, per bushel, 1 1/2 oz superphosphate of lime and 3/4
oz ground chalk or limestone

Cuttings compost is
7 parts by bulk medium loam
3 part by bulk moss peat
2 part by bulk coarse silver sand
To these is added a special fertiliser compounded of 2 parts by weight
of hoof-and-horn meal, 2 parts superphosphate of lime, and 1 part
sulphate of potash. For pots up to 4 1/2 in size, 4 oz of this
fertiliser is added per bushel of compost; for pots from 4 1/2 to 8in,
8oz; over 8in., 12oz


Janet
--
Janet Tweedy
Dalmatian Telegraph
http://www.lancedal.demon.co.uk