[The Red Baron]

Morning....just wondering if anyone has any experience a green roof? I was thinking about putting one on my shed.

[ptarmigan]

I think the important thing to remember is that your shed - or whatever you are building it on top of - has to be able to stand up to the weight of the green roof when it gets really heavy with rain.  There's one that someone tried at our allotments that looks distinctly creaky!

[The Red Baron]

Yeah I was thinking that, I'll give the shed a load test, I didn't build it but it's getting renovated at the moment!

[goodtogrow]

I've had self-sown sedum (alliteration!) growing on my flat garage roof for 20 years.

Got to thinking that certain herbs, eg Thyme, would do too.  If the sedum can grow in the dust caught up in the chippings on the roof so can something else.

Picking up on ptarmigan's point about weight my own experience would seem to be a solution for weak roofs, without re-inforcing them.  A pitched shed roof could have retaining boards fixed across it so that it ends up terraced like on hillsides.  A pitched roof would also provide the drainage so that there wouldn't be a weight build-up with rain, and the herbs would thank you for it too.

Just some thoughts to share.

Tom