A little further spelunking in the depths of the Internet reveals the following recipe for mixing one’s own John Innes formulations. I will try them this spring.
MissingHenryMitchell
Cultivating a habit of observation.
A little further spelunking in the depths of the Internet reveals the following recipe for mixing one’s own John Innes formulations. I will try them this spring.
MissingHenryMitchell 
Thanks for the info, I’m going to try them too. I was looking over your link and saw a soiless mix for seed starting that was basically 3 parts peat to one part sand…. I can manage that one! I haven’t been happy with any of the potting soil and seed starting mixes which are available in stores, plus they are (in my opinion) expensive for what you get. A bale of peat can still fit into the budget, and it’s about the same price as a big bag of the standard MG potting soil.
Now about the others I’m not sure. Sterilizing loam isn’t something I want to deal with, plus loam isn’t exactly lying around here…. My second option is to contact one of the greenhouses and see if I can buy a bale of potting soil from them, they seem to have access to the good stuff!