Should we care? Or does the myc care? Where's it's natural source of nitrogen, the soil I assume? Mine will eventually make it to soil, but I know people just spread woodchips to keep it growing.
Grain is mostly nitrogen and wood is mostly carbon? I see what you are getting at.
The agar is grain water (grain/brewed coffee/gypsum), the wood was also boiled the same as my grains, coffee + gypsum. (highlighting nitrogen sources?). I see slightly faster growth in my agar/grain (hyphenation expansion).
Do wood lovers look for decomposing bark that has more nitrogen? I just assumed they run till they find some tasty wood and go to town.
I went down the same path and did the same thing.......because of contamination issues with using grains.....and then I built a flow hood..... 
The fungus cares and indeed the soil is the place.....Many of these species are found naturally in riparian environments in fact, which is surely an organic, and inorganic, grinding zone for materials...(floods, ice, stones, soils, and gravels etc)......
Then washed up onto shore and deposited, in a creek or river bottom......
They will run until they find what they need, survival is obviously the top priority.....I try to look at it exactly the same as adding the green matter to the compost heap
A
Edited by Arathu, Today, 05:07 AM.