Grassroot democracy is definitly not equivalent to populism.
Grassroot democracy is (hopefully) enlightened, extra-parliamentary and an essential force for any change.
Just as its an banal influence, regarding contemporary political values, which in turn hopefully result in democratic improvements, I will be able to argue my standpoint.
Example: female suffrage.
Populism is an idea which is supported by the public oppinion However, they generally lack suportative evidence and most commonly is based in ignorance and prejudice.