It is possible to swap blocks with seeds, which places the seeds on top of any block. They can even grow there.

While this wasn't originally intended behavior, it feels like a useful feature for decorating purposes, so I am now deciding to keep this in

Alright, but I thought I would also suggest this:
Granted, I don't know how much work it would be, but maybe a config option that enables or disables that behaviour would be a nice way to show it is intended?

I'll add it to the features list on CurseForge but still great idea, will add that to the 2.0 update roadmap!

almost a year later because I somehow never ended up publishing the file, but this is now live in version 2.0