I’d say you can probably get away without the grain.
You should read this, to learn more about the technique I used to produce the fruits.
https://www.shroomery.org/forums/showflat.php/Number/28011928/fpart/all/vc/1
Discussion
Grain like Wild bird seed or millet or popcorn or something like that is pretty core to mushroom cultivation generally. There’s some things that aren’t worth the effort to improvise on.
Our time is as valuable as our money, and failed experiments cost a lot of time.
but at the same time, the lessons are invaluable, you may recall i mentioned that i wrote the elfspice tek
i have a bit of breathing room these days so i'm going to experiment in a couple of areas but keep to the track otherwise
nice link, definitely more interested in wood lovers but no harm in adding various kinds of seed if they help... popcorn and millet are both easy to come by