How to Test Soil Drainage

Many plants require "well-drained soil," but what does that mean? A simple percolation test reveals your soil's drainage class.

The 12-Inch Hole Test

1. Dig a hole 12 inches deep and wide.
2. Fill with water and let it drain completely (this saturates the soil).
3. Refill and time how long it takes to drain.

Interpreting Results

• Under 1 hour: Excellent drainage—may need organic matter to retain moisture for some plants.
• 1–4 hours: Good drainage—suitable for most landscape plants.
• Over 4 hours: Poor drainage—consider raised beds, drainage tile, or water-tolerant species.

Next Steps

• Native plants adapt to local drainage; exotic plants often need amendment.
• Consult a local nurseryman—they know which plants thrive in your soil and how to amend for others.
• Remember: many beautiful plants tolerate poor drainage (e.g., bald cypress, buttonbush, iris).

Test several spots; drainage can vary across a property.