A percolation test is helpful for figuring out how well water drains in your soil. Use the simple methods below to get a sense whether your soil drains well, is average, or drains poorly.
- Dig Hole: Dig a testing hole approximately 1 ft in diameter and in depth in the area of interest. If you will be testing a large area, consider digging multiple holes to better understand your property.
- Fill Hole with Water: Saturate the hole by filling it with water and allowing it to sit overnight. Saturated soil will give a more accurate test reading.
- Refill Hole with Water: The following day, refill the hole with water.
- Measure Water Level: Lay a straight edge, such as a stick or pipe, across the top of the hole. Insert a tape measure or metre-stick and determine the depth of water.
- Measure Drainage Every Hour: Measure the water level hourly until the hole is empty. Note each measurement.
Ideal Soil Drainage
Ideal soil drainage is approximately 2″ per hour; however, soil within a range of 1-3″ per hour will accommodate plants with average drainage requirements.
At a rate less than 1″ per hour, you will either need to improve soil drainage or select plants that thrive in wet soil.
At a rate over 4″ per hour, drainage is too fast.
Improving Soil Drainage
- To help clay soil drain or sandy soil hold moisture, incorporate plenty of compost and organic matter into the soil.
- Select plants that thrive in your soil drainage situation.
- Raised beds allow you to control the soil texture, and can be an easier way improve plant growth while still retaining precipitation.