The key amendment needed to improve the physical, chemical, and biological properties of sandy soil is organic compost. Sandy soils tend to suffer from drought stress and nutrient deficiency. Adding organic compost increases the water-holding capacity of soils. Compost also increases sandy soils' ability to hold and release essential nutrients. Finally, compost seems to improve seed emergence and reduces soil crusting.
Improving soil structure occurs over time by yearly additions of compost. Add and incorporate 2 inches of well-aged compost into the top 6 inches of soil. Mulch around the base of existing plants with 3 inches of organic matter, such as compost, shredded bark, grass clippings, or straw. The organic matter will slowly be incorporated in the soil. Mulches suppress weeds, reduce soil erosion, moderate soil temperature, and conserve soil moisture.
On sites with little topsoil, you may want to build a raised bed and fill it with a combination of purchased topsoil and compost. Finally, you should select drought-tolerant plants. Bulbs and rock garden plants thrive in sandy soils. Create a compost bin to recycle your yard waste.
If you examine the bedrock exposed in the steep hillsides in southeastern Minnesota, you will find that it consists of more than one kind of rock — sandstone, shale, dolostone, and limestone. Geologists have assigned names to such individual layers of rocks. The names of the individual rock layers are from places where they were at one time well exposed. St. Peter sandstone was named for an exposed rock layer found near the St. Peter (now Minnesota) River near Fort Snelling. The St. Peter sandstone was deposited during a slow rise in sea level that followed an extended period of low sea level and erosion across much of Minnesota. This prehistoric layer of unbroken rock supplied minerals to the soil layers above. In most of Minnesota, bedrock is buried deep under the topsoil, subsoil, and parent material. The parent material of many soils in eastern Minnesota, western Wisconsin, and northern Illinois have a St. Peter sandstone layer.
