Xisca Nicolas wrote:No, it will not be enough...
It depends if it is bed rock, then no.
If it is rocky soil, stones with earth, then you will hold more water of course.
I tell you what people say here: stones keep water in the soil.
Of course, if there is also earth, they mean that stones help stopping evaporation.
I have also read an ebook saying to forget about no irrigation through drought when you have a shallow soil.
You need 3 feet and more to keep water.