Dealing with Rocky Soil

One of the most difficult challenges gardeners face is that of trying to grow plants in rocky soil. Imagine placing a seed onto a stone slab and expecting it to take root. Logic dictates that a plant won't grow on a rock slab, and the same holds true even if the rock is just under the surface of top soil. Since roots require nutrients from soil to grow, along with sun and water, plant roots cannot penetrate through rock to find the nutrients and water they need to survive. So, what can you do if you discover that your soil is rocky? While you can take extreme measures and hire a backhoe to burrow through rock, or even more drastic, blast through the rock, even those procedures might not alter the soil to the degree plants need to grow.

Instead, consider supplementing the existing topsoil with more soil to create at least a foot of growing soil above bedrock. The steps to amend soil for growing are simple enough. Follow these steps to amend rocky soil to create a perfect growing environment:

1. Create compost to use in your existing soil from wood bark, wood chips, manure, leaves, leaf mold, grass and plant trimmings, stems, stalks, branches, and paper. Throw onto the hap any other organic matter you have, but take care not to use weeds or foodstuffs such as meat.
2. Till your rocky soil with a garden tiller, and remove obvious large rocks. This step may take several days, depending upon the amount of soil you want to amend.
3. Dump your compost on top of the tilled soil and till the area again and again.
4. Continue to add compost over several weeks until you have at least one foot of rich soil to grow your plants.

While you could simply apply a layer of composted material and soil over the compacted rocky soil, doing so is counterproductive since the roots of plants go in search of water and food. The roots won't penetrate the rock and will, instead, wither and die. It is much better to take several months or years creating a perfect layer of growing material for your plants, rather than to rush and just have a few inches of pretty—but unusable—top soil.

You may also consider working with what you have and find plants that will grow in rocky soil. Visit your local extension office, or speak with the staff at a qualified nursery to determine which types of plants will grow in your local rocky soil, appropriate for your growing zone.