You will most likely to come across rocky topsoil when building a new garden plot in an area you did not previously use for gardening. You may face rocky topsoil if the previous homeowner or tenant had covered your flowerbed with decorative rocks. Removing rocks from topsoil can be a difficult and time consuming task, but some tips and techniques can make it easier.
If you can see a few large rocks that won't scoop up easily with the soil, remove these by hand. Remove any layers of decorative rocks with a shovel. Continue until you have reached the topsoil beneath the decorative rocks.
When dealing with rocky soil, pick out the rocks by thoroughly sifting the soil. Purchase soil sifters at your local home-supply or garden store.
If you cannot find a sifter that meets your needs, make one yourself from scratch. Nail together four two-by-four boards to make a frame for your sifter. The frame should sit comfortably over the wheelbarrow or bucket you will use to catch the soil. Fasten a large piece of hardware cloth or other wire mesh to the frame to complete your sifter. Keep in mind that the size of the mesh will determine the size of the rocks that are sifted out. A large mesh will not catch all of the rocks, while too fine a mesh may catch too many pebbles and small pieces of debris.
After setting up your soil sifter over a bucket or wheelbarrow, begin sifting. Spread the topsoil over the soil sifter one shovelful at a time. Spread the soil out and rub it over the sifter to work it through the mesh. If using a small screen, hold and shake it to work the soil through. The rocks will stay on top of the sifter, while the soil will pass through into the container below. Discard the rocks after each sifting. For extremely rocky soil, use two different sizes of mesh. Begin with a large mesh to catch the biggest rocks, then sift the soil again through a finer mesh to sort out any smaller rocks.