Understanding what lies beneath what we see in our gardens is the critical step to successful planting. Not only do we want to plant more plants to cover and protect the soil to keep it from eroding and washing into streams, we want to boost the soils to help plants flourish.
are the ideal companions to streams and the Bay, protecting waters better than anything else. Your mission in the garden, should you choose to accept it, is to help make your garden soil function as well as the forest floor.
Problem is, most of us don't live or garden in forests anymore. Since the Dust Bowl era, we've learned to quantify the wisdom of ancient farming practices used before World War I. It took the Dust Bowl for us to get it.
As per the U.S. Department of Agriculture's Soil Survey, most soil science textbooks identify ideal, living soils as being made of the following:
- 45 percent minerals (rocks broken down over the millennia)
- 25 percent water
- 25 percent air
- 5 percent organic matter/biologically active/living matter (humus, compost, decomposing leaves)
Think of the soil structure in terms of layers. The minerals and organic matter are only half the story, but an important half. They provide and make nutrients plants need to produce their own food.
Organic matter and air are near the surface. Minerals, rocks and bedrock are further down. Plant roots need to be able to tap into minerals and water in the lower layers.
Nothing gets to the roots without water.
The final critical component of healthy soil is air. Yes, air. Soils could be squeezed together into a clay-like ball if bulldozers or heavy equipment have ever been present on your property. That could result in a lack of air needed for healthy root and plant growth.
Soils in our area that have been disturbed by construction only absorb 75-85 percent of rainfall, according to the Virginia Department of Conservation and Recreation's Virginia Runoff Reduction Method worksheet. These soils have 15-25 percent stormwater runoff along with sediment, phosphorous and nitrogen that plants could have used on land.
Restored and reforested soils capture and absorb 95-98 percent of rainfall. Only 2-5 percent runs off into the Bay.