My house has an extension, with a long, ugly, flat gravel covered roof.
It faces south, and I'd really like to get some pots on it with nice
plants in them, but does anyone know if this would be too much strain
for the roof?

Is there light compost one can buy for roof gardens, and if so what is
it?

I'd be grateful for any advice about roof gardening.

Many thanks in advance,
--
Jane Lumley