Poor lawn drainage

Poor lawn drainage

Does water sit on your yard for hours, if not days, after a rainfall? Poor lawn drainage is a problem that can be fixed.

Problems often associated with poor lawn drainage

  • The biggest landscaping problem associated with poor lawn drainage is that most plants are not adapted to water clogged soils.
    • Turf grass suffers from root rot, if sitting in water too long. Moss on the other hand, never gets too much water. So poor lawn drainage tends to tip the balance in favor of moss over grass. For information on low growing plants well adapted to wet soils, see Wet groundcovers.
    • Most trees and shrubs are also not adapted to growing in water saturated soils. They also suffer from root rot and lack of oxygen. Some trees, such as bald cypresses and red maples, are better adapted to such conditions. For more information on plants that do better in locations with poor lawn drainage, see either Wet sun plants or Wet shade plants.
  • Another big annoyance that comes with bad lawn drainage is that you can’t enjoy your yard, let alone walk on it, until the water has completely dried out, which can take days. Walking on a wet lawn can cause soil compaction, which is also bad for your plants.
  • And last but not least, sitting water may slowly sip into your house foundations, possibly causing cracks, mold, and other unwanted problems.

Identifying the source of your lawn drainage problem

The first step to fixing your problem is to understand it. Start by observing how water gets on your yard, and how it flows or sits. Then, you need to think about what you want to do with your landscaping and to consider possible options.

Let’s start at the beginning:

  • Lawn drainage is never instantaneous. In other words, rain water is never completely absorbed immediately by the soil. On lawns especially, roots can create a thick barrier that can greatly reduce soil permeability. Soil compaction may also be an issue. For more information on soil compaction and lawn aeration, visit our page on Lawn aerators.
  • Water always follows gravity and therefore ends up in the lowest point. When water falls on the ground, if it can’t penetrate the soil, it runs down to wherever gravity may pull it. And then it may get trapped, if the place to which it runs happens to drain poorly.

So the two most important issues pertaining to lawn drainage are soil permeability and yard topography. Consider where the water is coming from and how it travels on your yard.

  • If a fair percentage of the water actually trickles down from elsewhere (your roof, your driveway, for instance) and ends up on your yard, then you need to find a way to divert the excess water, possibly using drains.
  • If the rain falls directly on your yard and just sits there, then there are a few options.
    • You could work on the nature of your soil and the topography of your yard, as explained below.
    • You could also consider installing drains.
    • If the problem is not too major, you could simply get wet plants or create a rain garden.

All these solutions are explained in more detail below.

Soil permeability 101

Soil permeability must always be considered when dealing with a lawn drainage problem. Roots, be they grass roots, tree or shrub roots, can form a thick carpet that reduces water penetration. Add soil compaction in those locations where there is more circulation and the surface of the soil forms an almost impenetrable barrier. These factors not only create a lawn drainage problem, they also cut the flow of the air needed to sustain the living soil below.

You can test for roots and soil compaction simply by driving a spade into the soil. If it is really hard, then chances are that your soil is quite compacted. Also have a look at the layer of roots that may be blocking the water.  Aerating your lawn will let both water and air get below the surface.

Working on the nature of your soil

Another frequent lawn drainage problem comes from the soil itself. The presence of organic matter and sand in soil promotes lawn drainage. The presence of clay, on the other hand, makes soil much less permeable. To know the composition of your soil, you need to have it tested. Many nurseries offer this service. Call in advance and ask what they need to run the test. The test should basically tell you how much clay there is in your soil, but it may also tell you if your soil is lacking specific nutrients.

If in fact, you do have a lot of clay in your soil, then you have two options.

  • You can grow plants that like soils rich in clay. These plants will eventually change the nature of your soil, but this is a long term process.
  • You can add things that will change the nature of your soil, and make it richer and more permeable. There are two ways to do this:
    • The chemical method: Gypsum and limestone are known to break up clay. Neither of these products are really efficient if you merely spread them over the soil. You need to mix them up with the soil. A layer of soil of a least six inches is usually recommended. And don’t expect results in the same month. It can take years for results to be really apparent.
    • The natural approach. Organic matter mixed in with the soil will not only break up the clay, but it will make the soil richer and more alive, as well as help plants grow. It will also attract worms that will make the soil even more permeable to water and air. You can use a mix of compost, dead leaves, wood chips and tree bark. Adding roughly 15% horticultural sand will make the mix lighter and more permeable. Six inches of organic matter mixed in with your own soil should go a long way toward fixing your lawn drainage problem. Add a few landscaping trees or shrubs and you may be on your way to a perfect lawn. Using green fertilizers may also help change the composition of your soil.

Yard topography

The general shape of your yard should drive water away from your house and yard naturally. A lawn must have a small slope going from the house to the street. This way, rain water naturally flows away from the house and into the street. If it is apparent that the shape of your yard plays an important role in your lawn drainage problem, then some reshaping may be in order. The slope can be small, but the shape needs to be regular. If there is a depression somewhere, water may accumulate there.

Diverting excess water

Any yard can have a hard time absorbing excessive quantities of water. In cities and suburbs, most of the space is covered by buildings and materials that are not permeable to water, so rain trickles down to wherever it can.

If your lawn is surrounded by large roofs and driveways that all spill their rain water in the same direction, and if all that water ends up on your yard, it’s no wonder that lawn drainage is an issue. Diverting excess water away from your yard may fix most, if not all of your problem.

There are many ways to divert rain water. Here are a few things to consider:

  • Roof gutters can divert water very efficiently. Just make sure that the water doesn’t end up where it will create new problems for you or your neighbors. If the problem comes from your neighbors, getting them to fix the problem may be a big problem in itself.
  • If you also have problems with water seeping into your foundations and damaging your house, you should probably install a French drain around the house. French drains are very efficient if well installed and connected to the sewer system. Most of the water falling from your roof would simply be evacuated by the drain.
  • For asphalt covered driveways, a sump connected to the sewer system is the most efficient solution. Gutters and draining pipes driving the water away can also be efficient. Stone covered driveways are more permeable and can therefore also be a solution.

French drains and yard drains

French drains swallow up the water accumulating around the foundations of your house, while yard drains can drain water from anywhere on your yard.

  • In a setup where you have a French drain and yard drains, the yard drains may be connected to the French drain and the whole thing connected to the sewer system.
  • If you only have yard drains, then they may be connected to a dry well. Granted that this is possible, you could also let the water escape to a stream.

In both cases, a good layer of gravel on top of the drains will help the water reach the tubes. And do ensure that the tubes are sloped so as to let the water flow towards the escape route, and not the other way around.

Installing drains is a big job that will in most cases require that you dig out many plants while the work is being done. Ensure that you leave enough roots on your plants, that you then protect both the plants and their roots from the sun and from overheating or freezing, and that you don’t let the roots dry out. A good natural fertilizer will help your plants grow roots faster when you put them back in the ground. Note that spring and fall are the best seasons for such undertakings. Doing this when the weather is likely to reach extremes is not a good idea, as many plants may simply not make it through.

Finally, be sure to check what local regulations say on drains and excavation works.

For videos explaining how to install lawn draining equipment, you may visit Youtube.

Getting wet plants

One way to help with lawn drainage is simply to use plants that thrive in water and that drink up a lot of it. If your yard is sunny, go for wet sun plants, if its shady, go for wet shade plants.

The pros:

  • This is the most natural solution. No chemicals are needed.
  • This is an easy solution. You won’t have to turn your whole yard upside down.
  • With time, these plants will actually improve the quality of your soil and make it more permeable.

The cons:

  • This is not a fast solution. Things will only get better as the plants grow.
  • If you like a grass lawn, planting bushes everywhere may not be for you.

Adding a rain garden to your landscaping

A rain garden may be the solution to your problem. Note that if your whole yard is made up of clay soil, a simple rain garden is not the answer to your problems.

For more information on how to fix problems, see our page on Lawn problems.

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