Seed Germination - Role of Compost / Perlite / Vermiculite

That's been very much my experience too. I see Vermiculite and Perlite referenced as if they are interchangeable, but Vermiculite seems to hold a lot of moisture and make quite a soggy mix.

I'm going to stick to using Perlite mixed with multi-purpose compost (about 1:2 or 1:3) for cuttings and Vermiculite as a covering for surface-sown seeds. Its really light, stops the surface getting algae-green (i.e. by covering it) and the seeds I have grown seem to have done well, so I assume it helps