by Ron Alexander
Every successful landscape begins with healthy soil.
While plants often receive most of the attention during landscape design, the condition of the soil ultimately determines whether those plants thrive or struggle. Unfortunately, many construction sites begin with soils that have been stripped, compacted, depleted of organic matter, or otherwise damaged during or before development.
The good news is that these soils can often be restored. By understanding soil characteristics and improving soil health before planting, landscape architects, contractors, and property owners can create landscapes that require less maintenance, use water more efficiently, better withstand climate extremes, and remain healthier for decades.
Why Soil Health Matters
Healthy soil does much more than hold plants upright.
It stores water, cycles nutrients, supports beneficial microorganisms, improves air movement around roots, filters pollutants, and helps regulate stormwater. Healthy soils also capture and store carbon, making them an important tool in creating more climate-resilient landscapes.
Improving soil health can help:
- Reduce plant loss
- Lower maintenance costs
- Reduce irrigation requirements
- Increase stormwater infiltration
- Support healthier root systems
- Improve long-term landscape performance
Most Landscape Soils Need Improvement
Across much of the Mid-Atlantic, native soils tend to be heavy silts and clays that are naturally dense and low in organic matter, which makes them prone to compaction.
Construction activities often make matters worse by:
- Removing topsoil
- Compacting subsoils with heavy equipment
- Reducing soil depth
- Destroying soil structure
- Limiting root growth
Even soils that begin in good condition can become severely compacted during construction if they are not properly protected.
Compaction Is the Hidden Enemy
Soil compaction is one of the most common causes of landscape failure.
When soil becomes compacted, the large pore spaces that normally hold air and water are compressed. Roots struggle to penetrate the dense soil, oxygen becomes limited, water infiltrates more slowly, and runoff increases.
The effects extend well beyond plant health.
Compacted soils contribute to:
- Poor drainage
- Increased stormwater runoff
- Greater erosion
- Reduced groundwater recharge
- Greater irrigation needs
- Slower plant establishment
Even relatively small increases in bulk density can begin restricting root growth, particularly in fine-textured soils.
Soil Testing Should Come First
Before selecting plants or specifying soil amendments, it’s important to understand existing site conditions.
A quality soil test can evaluate:
- Soil texture
- Organic matter
- pH
- Nutrient levels
- Salinity
- Other physical and chemical characteristics
Equally important is working with a laboratory that provides practical recommendations and can help interpret the results.
Good soil testing not only identifies problems—it also helps to determine the best solution for each site.
Organic Matter Is the Foundation of Healthy Soil
If there’s one measurement, most soil scientists encourage landscape professionals to focus on, it’s organic matter.
Organic matter serves as the engine that drives healthy soils.
It feeds beneficial microorganisms, improves soil aggregation, increases water-holding capacity, stores nutrients, and supports the complex biological community often referred to as the soil food web.
Rather than viewing soil as simply sand, silt, and clay, we now understand that healthy soil is a living ecosystem.
For most landscape applications, we recommend striving for approximately 4–5% organic matter by dry weight whenever practical.
Organic Matter Improves Soil Structure
Adding stabilized organic matter creates benefits that extend far beyond increasing fertility, it greatly enhances soil structure.
As microorganisms break down organic materials, they produce natural compounds that bind soil particles into stable aggregates.
This improved structure creates larger pore spaces that:
- Improve moisture percolation / infiltration
- Improve aeration
- Reduces compaction
- Encourages deeper rooting
Better soil structure benefits nearly every aspect of plant growth.
Healthy Soils Hold More Water
One of the greatest advantages of improving soil health is increasing the soil’s ability to store water.
Research has shown that increasing soil organic matter by just one percentage point can allow soils to retain thousands of additional gallons of water per acre.
That stored water becomes available to plants during dry periods, reducing irrigation needs while improving drought resilience.
Better Soil Means Better Stormwater Management
Healthy soils don’t just benefit plants—they also benefit communities.
Improving soil structure increases infiltration and reduces runoff, helping rainwater soak into the ground rather than flowing into storm drains and nearby waterways.
Healthier soils can:
- Reduce runoff
- Improve groundwater recharge
- Filter pollutants
- Reduce erosion
- Improve water quality
As rainfall patterns become more intense, soil health has become an increasingly important component of stormwater management.
Site Preparation Makes the Difference
Successful landscapes are built long before the first plant goes into the ground.
Proper site preparation should include:
- Evaluating existing soil conditions
- Protecting topsoil whenever possible
- Preventing unnecessary compaction
- Decompacting damaged soils
- Incorporating amendments before planting
- Restoring appropriate soil depth
- Installing mulch after planting
Protecting existing soil is almost always easier—and less expensive—than trying to repair severely damaged soil later after plant establishment.
Soil Depth Matters More Than Many People Realize
Different landscape plants require different rooting depths.
While turfgrass may survive with relatively shallow soil (6-inch depth, minimum), shrubs and especially trees require substantially greater volumes of healthy soil (18-24-inch depth).
Providing sufficient soil volume to allow for rooting development often produces greater long-term benefits than simply adding fertilizer after installation.
The best landscapes provide both healthy topsoil and suitable subsoil beneath it to support decades of root growth.
Organic Soil Amendments Can Restore Soil Function
Organic soil amendments have become one of the most effective tools for restoring disturbed soils.
Quality organic amendments can improve soils:
- Physically
- Chemically
- Biologically
Benefits include:
- Increased organic matter
- Improved aggregation
- Better water retention
- Greater moisture infiltration
- Increased nutrient-holding capacity
- Enhanced microbial populations
- Improved drought resistance
Products such as compost and Bloom are examples of recycled organic amendments that can help rebuild healthy soil while supporting sustainable landscape practices.
Research Continues to Demonstrate the Benefits
Field trials and university research continue to demonstrate that adding stabilized organic matter can:
- Increase water-holding capacity
- Improve hydraulic conductivity
- Reduce bulk density
- Improve nutrient retention
- Support healthier root systems
- Improve long-term plant performance
Research conducted by institutions including the University of Maryland and Virginia Tech has documented these improvements using Bloom soil amendments in a variety of landscape applications.
Healthy Soil Is an Investment in the Future
Landscape success isn’t determined the day a project is installed.
It’s measured years later by healthy trees, thriving lawns, resilient planting beds, lower maintenance costs, and landscapes that continue to perform despite changing weather patterns.
Healthy soil provides the foundation for all of those outcomes.
Whether restoring an existing site or building a new landscape from the ground up, investing in soil health is one of the most effective—and often most overlooked—ways to create landscapes that are both beautiful and sustainable.
Ron Alexander is a horticulturist, author, educator, and one of North America’s leading experts on compost, recycled organics, and manufactured soils. With more than 40 years of experience consulting with landscape architects, municipalities, manufacturers, and the green industry, he has helped advance the science and practical application of compost and organic soil amendments. Ron has contributed to numerous books and authored hundreds of technical publications and is a frequent speaker on soil health, sustainable landscapes, compost utilization, and soil amendment technologies.
