Signs of Poor Soil Drainage

Clay Soil

• The presence of clay soil is a sure sign that the drainage in the area is poor. Clay soil is dense soil that does not provide good absorption. Loam soils contain sand and silt, making them loose and airy. This makes it easy for water to flow through the soil layers. Clay soil is compact, pliable and sticky when wet. The lack of porosity gives water nowhere to go, resulting in pooling. Clay soil is either red or gray, gray being the poorest of all the soil types.

Standing Water

• Pools of standing water are signs of poor soil drainage. If the soil does not absorb water efficiently after rainfall, the rainwater will sit above the soil line until it evaporates. Any standing water that remains for a long period can become stagnant. Stagnant water is a breeding ground for mosquitoes, providing them with everything they need to survive and lay eggs. If you see a high mosquito population, it is yet another sign of poor soil drainage.

Moss Growth

• Moss is a big fan of stagnant water. This rootless, non-vascular plant produces a bright green carpet wherever it grows. A musty, sour odor often accompanies the moss. The idea that moss is a sign of acidic soil is a misconception. In reality, moss can survive in neutral and alkaline soils just as well as it can in acid soil. Moss is a common find in compact clay soils. If you see moss in your yard, drainage is poor in the sports where it grows.

Percolation Test

• It is possible to test soil drainage prior to planting. Dig a hole measuring 24 inches in depth. Fill the hole to the top with water and let it sit overnight. Refill the hole again in the morning and observe what happens. Soil with good or moderate drainage will absorb the water at a rate of 1 inch or more per hour. If less than an inch of water recedes within an hour, or if the water fails to recede at all, drainage is poor.