Mysterious Grass Action

There is a mysterious smattering of what appears to be grass that has somehow managed to coat the balcony and everything on it.  Weird?  Very.  It's the type of weird that makes you wonder if the pigeon has been launching sneak attacks.  In the form of grass.  I first noticed it when I was out checking the plants.  I realised that their leaves were covered in the tiniest film of grass.  I had sprayed their foliage the night before and wondered if I'd some how managed to put grass in the bottle and sprayed it over them.  Then I remembered that I would remember if I had put grass in the bottle.  Why would I put grass in the bottle?  I wouldn't.  That's just silly.  And it didn't make sense that it would be the bottle as everything was covered in this film of grass.  It was over the floor, the chairs, the table, the BBQ cover.  It was everywhere.  It was like someone had done their lawn mowing, emptied their cuttings into a blender, chopped up the cuttings, blended them again, bagged them up, snuck onto the balcony and let them loose.  I can't imagine I've angered anyone enough to make them want to partake in grass rage but maybe I'm being persecuted by association.  Maybe there are some angry cricket fans out there who know where the poms live.  The thing is, we had some wind and rain and maybe I could accept that the weather whipped things into a frenzy before dumping it on my balcony but there's just not that much grass around us.  We all have balconies.  Sand would make more sense than grass!  So the mystery continues and as I haven't yet had time to get my broom out, the balcony remains covered in grass.  Maybe I should take a sample as evidence.  In case the grass fiend strikes again!