Before the first tree, shrub, perennial, or groundcover goes into the ground, the most important step is soil preparation. OK, the hardscape is in. Time for the softscape—what we at Details Landscape Art call exterior decorating.
Successful planting depends on the planting medium. A beautiful plant installed in poor soil will struggle. A properly prepared soil base gives plants the best possible start and greatly improves their long-term success.
The Importance of Soil Preparation
Soil preparation consists of two basic elements: grading and soil amendments.
Grading is one of the less glamorous aspects of landscaping, but it can be critical. Not every project requires grading, but where the ground is lumpy and bumpy, too steep, or draining in the wrong direction, grading may be necessary before planting begins.
Once the site is properly graded, attention turns to the soil itself.
Details Landscape Art has been serving homeowners throughout Sonoma County and the North Bay since 1991. During that time, we have encountered almost every soil condition imaginable—heavy clay, sandy soils, rocky ground, and everything in between. Each presents its own challenges and requires a different approach.
Soil Preparation – Working with Heavy Clay Soils
Much of Sonoma County is blessed—or cursed, depending on your perspective—with heavy adobe clay soil.
During the dry season, clay can become rock hard and difficult to cultivate. During the wet season, it can be sticky and difficult to work with. The good news is that clay soil is actually rich in nutrients and can be an excellent planting medium once plant roots penetrate the dense surface layer.
To improve clay soil, we often add nitrolized sawdust and compost-based soil amendments. The sawdust helps introduce air into the soil while the organic matter improves workability.
Where practical, we thoroughly rototill the amendments into the existing soil after softening the ground with irrigation. In some situations, particularly where only planting beds are involved, we may amend individual planting holes rather than the entire area.
Improving Sandy Soils With Soil Preparation
Sandy soils are generally easy to work with and provide excellent drainage.
The downside is that they are often nutrient deficient. Water and nutrients pass through sandy soil quickly, making it difficult for plants to access them over time.
In sandy conditions, we typically add composts and nutrient-rich soil amendments to improve fertility and water-holding capacity. Ongoing fertilization is also important because nutrients tend to leach away more rapidly than in heavier soils.
Dealing with Rocky Soil
Rocky soil presents a different challenge.
Large rocks often make rototilling impossible, so we typically amend individual planting holes with quality soil mixes and composts. Depending on the site, rocky soils may already contain adequate nutrients, but adding organic matter still improves root development and establishment.
Soil Preparation – Choosing the Right Soil Amendments
There are many soil amendments available from landscape suppliers.
Some of the products we commonly use include:
- Composts that add organic matter and nutrients
- Nitrolized sawdust for breaking up heavy clay soils
- Topsoil blends for improving planting conditions
- Specialty vegetable garden mixes
- Container and planter box mixes
Different projects call for different amendments. A vegetable garden has different requirements than a shrub border, and a raised planter requires a different soil blend than a lawn area.
The key is selecting the proper amendment for the specific application.
What We Don’t Do
One shortcut we never take is scraping away the existing soil and replacing it entirely with imported topsoil.
While that may look attractive initially, it often creates long-term problems. Soil amendments provide a temporary boost, but eventually plant roots need to grow into the native soil.
Our goal is to improve and enrich the existing soil, not replace it.
When properly prepared, the amended soil provides a healthy environment for new roots while encouraging plants to establish themselves in the native soil beneath.
The Foundation of a Successful Garden
Homeowners often focus on the plants they can see—the trees, shrubs, flowers, and groundcovers. But the real foundation of every successful landscape lies underground.
Proper soil preparation improves drainage, increases nutrient availability, encourages root growth, and helps plants establish more quickly.
Many contractors skip this step or do the bare minimum. The plants may survive, but they often struggle and grow more slowly than they should.
At Details Landscape Art, we believe that great gardens start from the ground up. A well-prepared soil base will reward the gardener with healthier plants, stronger growth, and a more successful landscape for years to come.