Part of my garden, a strip beside the greenhouse, is clay overlaid with a layer of pebbles, like a beach
![Roll Eyes ::)](https://chat.allotment-garden.org/Smileys/green/rolleyes.gif)
I'd like to build a raised bed on top, to grow mostly salad, and wonder what depth of extra soil/compost I could get away with adding? Obviously I'd have to buy in the soil/compost!
I don't know if the pebbles are an advantage with drainage, or if they'll stop any roots from penetrating
![wacko :wacko:](https://chat.allotment-garden.org/Smileys/green/wacko.gif)
Has anybody had similar experience?