Answer: It is no longer recommended to use liners as they impede the flow of water/drainage and/or hamper roots. The amount to apply depends on the size of the granite: the bigger the pieces the less is applied generally as it becomes difficult to walk on. Keep any mulch material (which is what DG is) away from the stems and trunks of plants by several inches, so it isn't scraping against plant tissue, otherwise it causes no problems. If you have significant sloping and water flow where run-off is an issue, you may want to consult a landscape architect.
Q&A Library Searching Tips