Anyone got advice on what might be able to grow in a space like this?
We are sandwiched between tall buildings, so it only gets direct sunlight when the sun is directly overhead near noon
We are in Sydney, Aus, so pretty temperate weather, but in the shade these pots never seem to dry out
Agreed. With that little sun, you'll only be growing shade and shade tolerant plants at best. Most common houseplants fit into this category.
And yeah, the soil is probably partly due to the makeup, and partly due to not being warmed by the sun.