Is soil testing necessary before fertilizing?
Written by
Nguyen Minh
Reviewed by
Prof. Martin Thorne, Ph.D.Soil testing is not just beneficial - it's crucial for thriving lawns. Problems caused by pH imbalances can result in nutrient lockouts that no planting soil or fertilizer will ever fix. I once identified manganese deficiency as the cause of a client's continuous yellow ryegrass after completing soil tests. They were spending $300 per season to try to fix the wrong problem with a specific type of fertilizer.
Sampling Best Practices
- Collect 6-8 cores from random lawn areas
- Avoid recent fertilizer applications (wait 6 weeks)
- Separate samples for problem zones
Key Metrics Revealed
- Exact N-P-K requirements
- Micronutrient levels (iron, zinc)
- Organic matter percentage
- Cation exchange capacity
Regional soil changes require site-specific testing. In Arizona's alkaline clay conditions, it makes sense to check soil pH annually. In Minnesota's acidic loam pH, it makes more sense to check soil acidity every three years. One of our clients in Phoenix adjusted their applications based on an 8.2 pH on their soil and saved 40% on fertilizer costs in the first year! With adjustments based on seasonal lime applications, those costs were spread across two seasons.
Advanced testing exposes problems that might otherwise go unnoticed. Most nutrient analyses including Cation Exchange Capacity (CEC) results tell you how much nutrients the soil can hold. Sandy soils in Florida (CEC < 8) require light feeds approximately every week. However, for CEC > 12 (clay soils), my clients have cut their applications by one-half, saving approximately $180/acre annually.
Read the full article: When to Fertilize Lawn: By Region & Grass Type
