canndo
Well-Known Member
Note: I prefer rye berries over popcorn (more easily uniformly hydrated, at least for me), but this is good general advice.
I have tried every kernel substrate you can imagine from bird seed to oats to brown rice to rye grass seed. Rye berries are in my opinion the best spawn material there is, if you know where to get it, it is cheap and it is usually clean. Popcorn will burst before it gets moist in the center, the kernels are too large and they don't do well as a substrate - BUT, as sprout says, it is easy to find and not very expensive.