There’s good garden soil, there’s not-so-good garden soil, and then there’s problem soil. It’s easy to blame the soil for problems you are having in the garden, but only a few soils have serious problems. This section is about them, and about telling whether you have a problem soil.
Most people have pretty good soil, some have great soil, and a few people have serious soil problems that they have to learn to live with. This section helps you understand problem soils and offers techniques for improving them or living with them.
One is always tempted to avoid soil problems by buying a few truckloads of good soil and just covering them over. This can cause yet more problems, however. Bringing in large amounts of soil should be thought of as a desperate measure, only to be tried as a last resort. Purchased soil might contain diseases or weeds that you don’t have. It can also cause drainage problems if it’s a different texture than your native soil. Try first to work with the soil you have, only bringing in more soil if necessary.
The word “heavy” comes from the feeling of working the soil, not its weight. Heavy soil is sticky, so it’s hard work to turn over a garden plot. Heavy soil is soil that is high in clay; it’s the clay content that makes the soil sticky. It can be plastic and sticky when wet, and hard as bricks when dry. However, heavy soil can be improved. In fact, a clay soil with good structure can be one of the best garden soils. For more information, and for techniques for living with heavy soil, see Clay Soils.
Sandy soil has no stickiness at all, and is easy to work. However, plants often don’t grow well in it—they dry out in hot weather and run out of food quickly. Sandy soils are often called “droughty” for their tendency to dry out quickly. For more information, see Sandy Soil .
Plants don’t mind rocks; they grow their roots around them, and often seem to prefer the cool moisture under a rock. But gardeners sure don’t like them. Rocks interfere with digging and seeds sprouting, and are a constant aggravation. For more information, see Rocky Soils .
Hillside gardening has its rewards, but also offers its challenges. Steep soil drains much too quickly, so it’s difficult to water. It also erodes during rainfalls, and soil can wash onto plantings, suffocating them. For more information see Steep Hillsides .
Soil can be eroded by both wind and water, or by both acting together. For more information, see Erosion.
The most common compaction problem is from foot traffic, but soil can also be compacted from heavy equipment or automobile traffic. Plant roots don’t grow well in compacted soil; they remain shallow and the plants remain small. For more information, see Compacted Soil .
Sometimes we are forced to garden in subsoil, the soil that underlies topsoil. This most frequently happens when a contractor strips off the topsoil in excavating for a home, and doesn’t replace it. Subsoil is usually deficient in organic matter and nutrients. It frequently drains poorly and is difficult to work. Even subsoil can be improved, however. For information, see Exposed Subsoil.
Acid and Alkaline Soils
Soils that are too acid or too alkaline are usually regional. All your neighbors have the same problem, and the local garden center carries the materials you need to correct it. For more information, see Acid Soils and Alkaline Soils.
Many low-lying gardens have a wet spot that never dries up, and grows its own set of weeds and soil problems. For information about them, see Wet Soils .