lettuces/rocket

[hilaryh]

will lettuces/rocket grow in a container 6" deep.
or anything else you can suggest

[WendyS]

I think this is a little shallow but if the compost in it is really bulky with lots of water retaining material in it, it's worth trying. I think rocket might be more successful than lettuce as some of the varieties can develop quite deep roots. The other thing you might be able to grow is "Cut & Come Again" mixed salad leaves which you pick when they are very small. Mustard & cress should also be possible. If you like herbs, basil will grow with its roots in shallow earth but it grows quickly so you will need to keep the compost well moistened and fertilised.