Garden Soil Percolation Test – Drainage Speed

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The capacity of water to percolate through garden soil and reach plant roots is impacted by the drainage speed of the soil.

If you are new to this blog my name is Ashley and I am a soil scientist. I am located in a Canadian Zone 3 and a USDA Zone 4. I write articles, make YouTube videos, Instagram & Facebook posts all designed for Canadians and Cold Climate gardeners using science-based methods. If you are looking for anything specific be sure to let me know in the comments down below.

Importance Of Soil Drainage

  • Good Drainage: Garden soil with good drainage allows extra water to swiftly flow through it, avoiding waterlogged conditions that can cause root rot and other issues. Additionally, good drainage makes it simpler for oxygen to reach the roots, which is necessary for strong plant development.
  • Inadequate Drainage: Water can build up in garden soil with poor drainage, resulting in wet circumstances. This could stop oxygen from getting to the roots, leading to root rot and other issues. Additionally, plants can be deprived of nutrients, which makes them more vulnerable to pests and diseases.
  • Affects Plant Growth: The amount of water available to plants and the oxygen content of the soil are both impacted by drainage, which may have an effect on the development and health of plants. Stress from an excessively wet or dry soil might make plants more susceptible to pests and illnesses.
  • Affects Soil Structures: Poor drainage can also result in soil compaction, which hinders plant roots’ ability to penetrate the soil and absorb water and nutrients. Drainage has an impact on soil structure.

Garden Soil Percolation Test:

Step 1: Dig holes around the yard 12” in diameter by 12” in-depth

Step 2: Fill each hole with water to the top and allow it to sit overnight. This is important because it will bring the surrounding soil to full field capacity.

Step 3: Refill the holes the next morning.

Step 4: Measure the water height by placing a straight stick across the hole and placing a measuring tape in the center.

Step 5: Repeat step four every hour until all the water is gone. Record the number of inches lost every hour.

An ideal soil drains at around 2” per hour but results between 1”- 3” per hour is considered acceptable for garden plants that have average drainage needs. If the drainage rate is less than 1” per hour, you will need to improve drainage to ensure healthy plants. Start by reviewing the soil type and compaction test results. If drainage is more than 4” per hour your soil does not have enough organic material to support water retention and is draining too fast.