>>979305Thanks for the reply! There is a lot of drainage because the bottom is basically just a bunch of vertical pieces of wood with inch-wide gaps between them. The soil is kept in with a black cloth. I guess I'll add another 20 litres of soil and that should be fine.
I actually completely agree with adding more screws because a single screw for each board is a bit shabby.
I'm planting: zuchini, beans, french beans, lettuce and kauliflower. Added a picture of one of my two trays of samplings. These pictures are a couple of days old so everything is a bit bigger now.