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Lawn drainage can be a major problem

Soggy lawn

If you have rain water that sits on your yard for hours and sometimes even days after a good rainfall, you have a lawn drainage problem. A problem that needs to be fully understood in order to be fixed.

Lawn drainage woes

  • The biggest problem with poor lawn drainage is that most plants, including turf lawn, do very poorly in sitting water.

  • Turf grass likes water, but too much of it causes root rot. Moss on the other hand, almost never gets too much water. Sitting water gives moss a foot hold on your yard, but also gives it a fighting edge against turf grass. So mosses thrive while your grass dwindles.

  • Another big annoyance that comes with bad lawn drainage is that you can't enjoy your yard, let alone walk on it, until all the water has completely dried out, and that can take days. You should know that walking on a soggy lawn can cause serious damage.

  • And last but not least, that sitting water may slowly be sipping into your house's foundations, creating headaches for years to come (cracks, mildew, etc.).

Identifying the source of your lawn drainage problem

The first step to fixing your problem is to understand it. This can be as simple as observing how water gets on your yard and then behaves once on your yard. This information will guide you to the best possible solutions to your own lawn drainage problem. Then, you need to think about what you want to do with your landscaping and to consider the 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 ground. Even on sand, rain drops can create a sort of glaze that will make the soil less permeable. On lawns, roots can create a thick barrier that can greatly reduce soil permeability. Soil compaction may also be an issue. This tends to happen, for instance, when people, vehicles, or machinery walk or run over a yard.

  • One thing is always true when it comes to lawn drainage: water simply follows gravity and always ends up in the lowest point there is. When water can't penetrate the soil, it either runs away or gets trapped somewhere.

So we have two basic issues pertaining to lawn drainage: soil permeability and yard topography. But let's delve a bit more into possible issues that could make a lawn soggy. Consider the following:

  • Where does the water comes from?

    • If a fair percentage of the water actually trickles down from elsewhere and ends up on your yard, then you need to find a way to divert the excess water.

    • If it's simply rain that falls directly over your yard and sits there, then there are a few options.

      • You can get wet plants.

      • You can work on the nature of your soil.

      • You can install drains.

Soil permeability 101

Regardless of the fact that water coming from elsewhere may end up on your yard, soil permeability is certainly a factor in your lawn drainage problem. Later on on this page, we will discuss the question of soil composition, but let's start with more basic issues: roots and soil compaction blocking the passage of water.

Roots, be they grass roots or tree roots, can form a thick water proof carpet that blocks water at the surface. 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 underneath.

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. You can then lift up the soil and have a look at the layer of roots that may be blocking the water.

Both these lawn drainage problems can be fixed by aerating your lawn.

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.

Diverting excess water

Too much water is just too much water. Any yard can have a hard time absorbing excessive quantities of water. In cities and suburbs, large areas of land are covered with constructions and materials that are not permeable to water, so the rain that falls on those areas ends up trickling down elsewhere.

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 may be an issue. Diverting excess water away from your yard may fix most, if not all of your problem. At any rate, it's an issue that needs to be addressed.

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

  • 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 bigger problem in itself.

  • If you also have problems with water seeping into your foundations and damaging your house, you may consider installing a French drain around the house. This is a big job, but a French drain is very efficient if well installed and connected to the sewer system. All the water falling from your roof would be instantly absorbed by the drain. You may even have an extension running along your driveway if needed.

  • 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 (see our page on patio building materials).

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.

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. This service is available in many nurseries. Call in advance and ask them what they need to run the test. They should ask you a few questions and then tell you how to proceed. 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 in 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 can be a long term solution.

  • You can change the nature of your soil, so as to 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, bring more life to your soil and 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.

Installing drains

If the source of the water cannot be diverted, if the problem does not have to do with the shape of your yard or the nature of your soil, then you may need to install drains.

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