Muckers Mulch is primarily designed to be used as a top dressing. We normally recommend you apply a depth of at least 1.5″ which is thick enough to ensure that weeds cannot come through and retain sufficient moisture. But in addition to being an efficient weed-suppressing mulch this product can also be used as a general-purpose soil conditioner. So the actual amount you need will depend on the type of soil you have as well as the area you wish to cover. If you are in any doubt about the quantity you require please contact us for further assistance.