Gardening in Rocky Soil

by Murray Anderson

Growing a successful garden in rocky soil is a challenge. Logic tells us that a plant can't survive on a bare rock face and whether the rock is on the surface or underground the effect is the same. Fortunately, even if you do have rocky soil you can still grow a beautiful garden, but it's going to take some work. Here's some ideas about gardening on rocky soil.

Preparing your garden

The first consideration when gardening in rocky soil is to start small, particularly if you’re working by yourself. Rocky soil is going to require ongoing effort and taking on a project that is just too large will be frustrating and quite probably, eventually overwhelming.
Choose the place in your yard that will make the best garden. A level area that receives good sunlight (but not all the time) and is open to some rain is ideal.
Start by getting rid of surface rocks. Use a sturdy rake to gather them, or if the rocks are large a shovel and/or a crowbar and wheelbarrow to physically move them out of the area. Consider stockpiling the rocks somewhere close by so they can be used to build a garden edging or for a stone wall or rock garden in the future.
After removing the surface rocks, use a roto tiller to turn the compacted soil over (and bring more rocks to the surface). Take your time and work slowly, there may be large rocks lurking just under the surface and they could damage your machine.
After raking up or removing any rocks your first tilling produces, spread a layer of compost, organic material (peat moss, organic fertilizer) or top soil over the garden area and go back over it with the tiller - turning the compost into the soil. Adding peat moss to your garden will help the soil retain moisture while organic fertilizer will provide nutrients to help the new plants grow strong and healthy.
You'll want to do this process at least twice (three times is better), so you will end up with a garden bed of native soil and compost or organic matter 8 to 10 inches deep.

Choosing your Plants

Different plants grow better in rocky soil than others. After all the hard work preparing your garden area, it's well worth some time to gather information about plants that grow well in your area.
Good sources of information include your local garden center (who will know as well as stock plants that thrive in your area) and perhaps a university or state colleges extension division that can provide information on gardening in your area. Other informal sources could be garden clubs, articles in local newspapers or simply knowledgeable neighbors.
The plants you choose will need to match both your hardiness zone and the amount of rainfall you receive in your area.

A word of caution

All this talk about removing rocks and tilling soil may sound like a lot of work and you might be tempted to just put down a layer of topsoil over the existing rocky soil. Unfortunately that low effort garden won't work well. The existing soil is likely hard and compacted and will prevent any plant roots from reaching down into it. Plus, the indigenous rocks are still there and they will effectively inhibit plant growth.

Murray Anderson is an experienced freelance writer with over 500 articles published on the web as well as in print magazines and newspapers in both the United States and Canada. He writes on a wide range of topics and is a regular contributor to DoItYourself.com. He can be contacted at murand@lycos.com.