Let's just say: I take my hobbies seriously! :D
That stuff in the back is 100 litres of perlite, a cheap, lightweight volcanic material that provides aeration in potting mixes! 🌱
The other main component is going to be coir (aka coconut fibre), which has the opposite property: it holds water really well! I found it in this brick shape.
Perlite looks and feels like small pebbles of styrofoam. It wasn't as dusty as I thought, but let's still give it a good rinse!
...and this should, in theory, be an excellent substrate for starting seeds! This is a "soil-less" mix, and it's pretty much void of nutrients; the seeds already pack everything they need to get started. Or so I've heard. I barely know what I'm doing! :D
@blinry sorry if it breaks your heart, that seems like waaay too much perlite :D
The surface layer should be as fine es possible for many seeds.
@holly
good to know, thanks for sharing!
I think it depends on the kind of plant. Mine wanted earth and didn't like too much perlite 😊 Maybe I should have made a better upper layer, too!
Mold can be a problem, but with quality soil and lower relative humidity / higher temperature it rarely is.
@blinry