Penn State guide to urban soil management to support safe, productive land use

UNIVERSITY PARK, Pa. — A just-released Penn State publication, “Guide to Urban Soil Management for Gardening, Farming, Horticultural Placements, and Green Infrastructure,” provides a comprehensive, science-based framework for assessing, testing and managing soils in urban environments to support safe, productive and sustainable land use.

Urban soils are highly variable systems shaped by past and present human activities, including construction, industrial use, transportation and landscaping, according to the guide’s first author, Patrick Drohan, professor of pedology in the College of Agricultural Sciences. As a result, he noted, they often contain mixed materials, altered physical properties and potential contaminants such as heavy metals or residual chemicals.

“The goal of this guide is to help people make informed, practical decisions before they begin gardening, farming or installing green infrastructure in urban spaces,” he said. “Urban soils can be incredibly variable. Some are relatively undisturbed, while others reflect decades of construction, demolition, traffic, industrial use, older housing, fill material or past agricultural activity. We wanted to give readers a way to slow down, look carefully at a site’s history and conditions, and then decide what kinds of soil testing or management steps are appropriate.”

The guide emphasizes that understanding this variability is essential for making informed decisions about urban gardening, farming and green infrastructure applications. It highlights the importance of consulting historical records, engaging community knowledge and recognizing high-risk land uses such as industrial sites, former orchards or areas near heavy traffic. A structured, step-by-step approach helps users select appropriate sites while minimizing risks to human health and environmental quality.

One of the main messages the authors wanted to convey in the guide, Drohan pointed out, is that urban soils are not automatically unsafe, but they should not be treated as unknown blank slates either.

“A vacant lot, schoolyard, former residential property or underused community space may have tremendous potential, but the safest and most successful projects begin with site assessment,” he said. “That means asking what was there before, who owns the land, whether there may be buried debris or contaminants, how water moves through the site and whether the intended use is food production, ornamental plantings, recreation or green infrastructure.”

The authors also wanted the guide to be useful to a wide range of people — not only soil scientists. Community gardeners, urban farmers, landscape designers, Extension educators, municipal staff, nonprofit organizations and neighborhood groups all need accessible guidance, Drohan explained, on issues such as lead, arsenic, construction debris, compaction, drainage, pH, nutrients, compost use and raised beds. The guide brings those topics together in one place and frames soil management as both a public health issue and a community-building opportunity.

Drohan said his hope is that the book helps people see soil as part of the infrastructure of a sustainable city.

“Healthy, well-managed urban soils can support food production, stormwater management, biodiversity, heat reduction and stronger neighborhoods,” he said. “But that only happens when projects are planned carefully and when risk is addressed transparently. We want people to feel empowered, not discouraged, by the complexity of urban soils.”

The first section of the guide focuses on site assessment, a critical step in determining whether a location is suitable for horticultural use. It outlines methods for evaluating land use history, identifying potential contamination risks, and assessing physical site characteristics such as sunlight, drainage and accessibility.

The second section addresses soil testing, providing practical guidance on both field-based and laboratory methods. Key soil properties — including texture, bulk density, drainage, pH, nutrient levels and contaminant concentrations — are discussed in detail. The guide explains how these parameters influence plant growth, water movement and nutrient availability, and emphasizes the importance of interpreting test results within a regional context.

Soil testing is presented as essential not only for optimizing productivity but also for identifying potential hazards such as lead, arsenic or other pollutants that may affect human and ecosystem health. The final section focuses on soil development and management strategies for urban sites. It addresses common challenges such as construction debris, compaction and contamination and provides recommendations for site preparation, soil amendments and ongoing management.

The guide compares in-ground gardening with raised beds, outlining conditions under which each approach is appropriate. It also discusses the use of compost and other organic materials, noting that excessive application can lead to nutrient imbalances or environmental impacts.

Throughout, the guide integrates considerations of human exposure pathways and risk mitigation, emphasizing personal responsibility and practical strategies to reduce contact with contaminants. It also highlights the broader benefits of urban soil management, including improved food security, community engagement, environmental resilience and urban ecosystem services.

Overall, the guide serves as a practical and educational resource for gardeners, urban farmers, planners and community organizations, Drohan said. By combining scientific principles with actionable guidance, it enables users to transform underutilized urban spaces into safe, productive and sustainable landscapes while addressing the unique challenges posed by urban soils.

The breadth of expertise behind the guide is unusual, Drohan suggested.

“The author team brought together perspectives on soil science, testing, urban agriculture, horticulture, risk and practical land management,” he said. “That collaborative approach was important because urban soil questions rarely fit neatly into one discipline. They involve science, history, design, community priorities and long-term stewardship.”

The guided was funded by the Pennsylvania Department of Agriculture and the Institute for Sustainable Agricultural, Food, and Environmental Science in the Penn State College of Agricultural Sciences. Download the guide free of charge.