Send soil samples to a lab or extension service

Collect soil from 6-8 spots across your garden at 6-8 inches deep, mix in a bucket, and submit 1-2 cups to your county cooperative extension service or a soil testing laboratory. Results typically include pH, nitrogen, phosphorus, potassium, micronutrients, organic matter percentage, and specific amendment recommendations.

Why It Works

Lab analysis uses standardized methods (hydrometer for texture, chemical extraction for nutrients) that produce precise, repeatable measurements. Extension labs also provide tailored recommendations for your region and intended crops. This is the only method that tells you exactly how much lime, sulfur, or fertilizer to add.

Tips

• Cost is typically $15-30 through a state extension service; some states (including North Carolina) offer free testing
• Test every 2-3 years, or annually if actively correcting a problem
• Spring is the best time to test, before amending and planting
• Home test kits are no substitute — university extensions consistently recommend lab testing over DIY kits for any amendment decisions