My kid had a science experiment at school where they added seeds to various substrates (rock, sand, dirt, etc), watered them, and measured whether they sprouted.
My kid was assigned rocks, and brought home his sad cup of rocks the next week asking if I could help the seeds sprout on the rocks. I said I couldn't, that seeds need dirt, but moss or lichen could survive if wet enough.
He then proceeded to gather moss outside and place it on the rock.


