Archive for Thursday, February 28, 2008

Poor drainage in yard easy to fix

February 28, 2008


I am happy about the moisture this winter because I know it is good for the plants, but the excess rain and snow is pooling in my yard - unsympathetically pointing out my drainage problems.

Many plants will not grow in areas that stay wet for long periods of time. Water fills the empty space in the soil, pushing out the oxygen that plants also require to survive. Extended wet periods essentially suffocate the plant.

Locate areas that are poorly drained now and determine the source of the problem so it can be corrected when the ground finally dries out. The most common causes of poor drainage are soil composition, compaction, and the grade or slope of the land.

An easy way to understand soil composition is to visualize the soil particles as larger objects. In your mind, picture sand grains as basketballs, silt as softballs and clay as marbles. If you had a large container of basketballs and poured water into it, the water would run through quickly because of the space between the basketballs. Also picture a large container full of marbles (clay). Water moves through the marbles, but it takes longer because the marbles fit more closely together than the basketballs.

Soil is actually a mix of sand, silt and clay particles, even if seems like only clay is present. If your large container were full of a mixture of basketballs, softballs and marbles, imagine the difference in how the water would move through the conglomeration. The softballs and marbles fill the space between the basketballs, leaving little space for water to flow.

¢ If your soil drains poorly because it has a high percentage of clay, add compost. Till or spade the compost into the existing soil. Have patience: Several applications over a period of time may be needed before the drainage increases. The improved soil quality is worth the wait.

¢ Compacted soils are improved in the same manner if they are in the landscape or garden. Mulch made from organic materials (like wood chips) will also increase the amount of organic matter in landscapes over time. If the compaction is in the lawn, core-aerate in September to improve drainage.

¢ If the grade or slope of the land is the problem, choose the best solution based on your situation. Build up soil in low areas by adding topsoil, keeping in mind the new direction the water will take. It is best if the topsoil can be mixed with existing soil. If the poorly drained area is in a lawn where it cannot be easily built up, core-aerate and de-thatch the lawn in September to improve drainage.

¢ Make an outlet for water to move from low spots. In one area in my yard, water stands on the sidewalk because the ground around it is higher. My goal this spring is to make one section lower so that water can easily flow from the concrete.

¢ Install a French drain. A French drain is a narrow trench filled with gravel that directs water to a specific location. If improperly installed, they can make matters worse, so do some research and seek advice if you think a French drain is the best solution.

¢ If your yard is draining well now, but you notice wet areas later this year, you may be overwatering. Reduce applications of water - plants are healthier and grow better root systems when watered deeply and infrequently.

Jennifer Smith is the Douglas County Extension AgentHorticulture for K-State Research and Extension. She can be reached at 843-7058 or


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