Quick answer
Take several small samples across the lawn, mix them together, and send them to a lab. In Oklahoma, county extension offices offer soil testing through Oklahoma State University.
How to Take a Sample
- Use a clean trowel or soil probe
- Sample the top few inches in 10 to 15 spots across the lawn
- Mix in a clean bucket and remove grass and roots
- Keep lawn, garden, and bed samples separate
What You'll Learn
Results typically show pH and levels of key nutrients, along with recommendations for what (if anything) to add.
How Often
Every few years is enough for most home lawns, or any time a lawn struggles for no obvious reason.