Outdoor & Protected Cultivation
Native Soil Testing & Amendment Decisions
Outdoor soil decisions should start with physical and chemical evidence. Texture, structure, drainage, pH, salinity, organic matter, and nutrient tests answer different questions and should not be replaced by a generic amendment recipe.
Key concepts
- Soil texture and aggregation affect drainage, aeration, and water storage
- Laboratory nutrient values depend on the extraction method used
- pH influences chemical availability but does not diagnose every plant symptom
- Adding amendments without a measured need can create excesses or imbalance
What to measure or observe
- Collect a representative soil sample using a documented pattern
- Record texture and infiltration separately from laboratory chemistry
- Review pH, soluble salts or EC, organic matter, and nutrient results with the lab method
- Retest after major changes when meaningful
Common mistakes
- Testing one handful from an unusual spot
- Treating bagged amendment instructions as a soil diagnosis
- Adding lime or sulfur without measured pH context
- Ignoring drainage because a nutrient test looks acceptable
Visuals this lesson still needs
- Representative soil-sampling map
- Texture-structure-drainage diagram
- Soil-test interpretation flow
- Amend-only-with-evidence decision tree