Urban Horticultural Production
Soil Testing in Urban Horticulture
Urban horticulture is expanding as city residents transform vacant lots, backyards, and community gardens into spaces for fresh produce, herbs, and flowers. These gardens enhance community health, biodiversity, and sustainability. However, urban soil often faces issues from contamination, compaction, and poor management. Soil testing is a vital first step for urban growers, revealing key information about nutrients, pH, organic matter, and possible contaminants.
This guide provides a simple, step-by-step approach to soil testing, helping urban growers create healthy, productive, and safe gardens.
Pair of gloves
Clean plastic bucket
Clean spade or shovel
Clean travel or soil probe
Ziplock bag or soil sample box (provided by testing lab)
pH extremes (too acidic or too alkaline)
Compaction and poor drainage
Heavy metal contamination (lead, arsenic, cadmium)
Excess salt from past construction or irrigation
Nutrient imbalances (too much or too little nitrogen, phosphorus, potassium)
Identify nutrient needs
Determine pH adjustments
Detect potential contamination
Avoid unnecessary fertilizer use
Reduce environmental harm
Support long-term soil health
Plan crop selection, amendments, and irrigation methods based on soil conditions
When to Test: Ideally, test soil 3-6 months before planting, especially if amendments are needed.
How Often: At least every 2–3 years for ongoing gardens. Test annually if growing food intensively or applying compost/fertilizer regularly.
| Lawn | 3-4 Inches |
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| Flower Garden | 4-6 Inches |
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| Shrub Beds | 6-8 Inches |
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| Vegetable Gardens | 4-6 Inches |
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| Trees | 4-8 Inches |
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| Pastures | 4-6 Inches |
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Look for different environments in your field or garden and collect separate samples from areas that are mostly sunny versus those in deep shade, or dry areas versus wet areas.
*Do not sample compost areas, under the dripline of trees, or near sidewalks and driveways.