Hi Edward (and Ken). I'm up to four of them now, 1 small, 1 medium and 2 large. The last large one is almost ready for plants but it's in another town not too far away so I have to haul all the plants over there still. The ground is covered in plain, gray gravel (like used in mixing cement) just to keep the weeds down and stop it from becoming muddy. The pumice, when wet, sticks like perlite. I don't know yet if it is "better", but it's a lot cheaper and I don't like the unnatural look of the bright white perlite.
Edward, see the post I did on the 'seedling greenhouse test'. It's only about 3 meters long and 2 wide and about 1.60 tall. (Here's an old picture);
It was pretty easy to make with a little cement, some PVC pipe and a few lengths of steel reinforcing bar. I have a really bad grasshopper problem around here so it's a necessity! Plus my house/yard is too full of trees and mostly too shady for neps to do well.
