Can you over water your lawn?

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Can you over water your lawn? The short answer is yes. An overwatered lawn can cause more issues than an under-watered lawn. In fact overwatering can lead to a large number of issues. To understand the problems and how to avoid them, read on.

Why is an overwatered lawn a problem?

  • Deprives the roots of oxygen
  • Washes nutrients out of the soil
  • Roots grow shallowly
  • Encourages spread of fungi and mushrooms
  • Encourages insect infestations
  • Develops thatch
  • Promotes weeds

Deprives the roots of oxygen. Soil is quite a porous medium in which the grassroots grow. Overwatering a lawn will saturate the soil and fill in the porous gaps in the soil. This forces the oxygen out of the soil and deprives the roots of what it needs to grow correctly. The grass will be weaker as a result and susceptible to other problems.

Washes nutrients out of the soil. Watering the lawn regularly will naturally wash the nutrients out of the soil. This can especially be an issue on sandy soils that are lighter in consistency and can’t retain minerals as easy. This will weaken the growth of the lawn over the course of the growing season unless it is treated with a lawn feed/fertilizer.

Roots grow shallowly. An overwatered lawn will have a plentiful supply of water near the soil surface. Grassroots in these conditions aren’t encouraged to grow deeply and therefore extensively into the soil. This again leads to a weaker plant.

Encourages the spread of fungi and mushrooms. Fungi love warm, damp conditions at the soil surface layer. This will promote the growth of the fruits of fungi – mushrooms. Although fungi are beneficial to lawns, mushrooms can be unsightly and spoil the look of your perfect lawn.

Encourages insect infestations. A shallow-rooted grass plant is susceptible to insect damage as the younger, softer roots are available at a depth that is the natural habitat of bugs. If you feel that insects are causing an issue on your lawn please read our guidance on some common lawn pests.

Develops thatch. As the shallower roots grow laterally through the top layer of soil, the soil can develop a mat like consistency that will begin to build up with other organic matter, known as thatch. Thatch (and moss), as well as looking unsightly, will suppress the growth of your grass.

Promotes weeds. A regularly saturated lawn will encourage the establishment of weeds such as crabgrass and nutsedge.

Watering a lawn.

Over-watered lawn warning signs

It can be difficult to judge if you are overwatering your lawn however mother nature has developed a good way of letting you know. The list below is some telltale signs that your lawn is becoming regularly over-saturated. Some signs are more obvious than others.

  • Yellow grass.
  • Mushrooms
  • Water runoff from the topsoil.
  • A squishy feeling when walking on the grass.
  • Weeds like crabgrass and nutsedge appearing
  • Thatch growth

How to prevent over watering of your lawn

The best advice to offer on how to water your lawn is water plentifully and infrequently. Ideally, you should water the lawn enough so that the water penetrates the first 4 inches of the soil. A good way of testing this is to wait 6 hours after watering the grass, and then push a screwdriver into the soil. If the screwdriver pushes into the soil with ease and pulls out cleanly, the soil is sufficiently wet.

Try to learn how long you need to apply the water sprinkler to your particular lawn. To do this, continue to use the screwdriver test for a few weeks, whilst trying different durations of watering. Over time, you will be able to perfect the amount of time needed to water, and therefore the amount of water required to water your lawn sufficiently.

The trickiest part of watering is to know how often to water. The answer to that conundrum isn’t as straight forward and will largely depend on your conditions. For this try to keep the following in mind.

  • Is rain forecast? If so, don’t water the lawn.
  • Has the weather been consistently dry and hot? If so, you will need to water more regularly.
  • Is your soil clay-based or sandy? Clay retains water more than sand and will, therefore, require less watering. Excavate a few patches of your lawn to learn what the sub-soil consists of.
  • Is your garden sheltered or exposed? Exposed gardens tend to be windier. Wind will dry your lawn quicker than a sheltered garden.
  • Is the grass actively growing? A lawn will require less watering if it isn’t actively growing. Grass in winter is dormant and won’t require watering. A lawn in early spring and late autumn will probably require no watering either as the grass won’t require much water and water tends to be plentiful during these periods due to the weather.

Remember that you can try pushing a screwdriver into the soil. If it is difficult to push the screwdriver into the first few inches of soil, it is probably time to water your lawn.

When to water new turf

Newly laid turf will require more watering than an established lawn. This is because the turf has a very shallow root length and therefore can dry out much more quickly.

Fresh turf may require daily watering, especially if the weather is warm and rain isn’t forecasted. You will only need to apply enough water to penetrate the new turf as well as the first inch or so of the soil below the sod.

This will encourage the roots to grow into the sub-soil to find more water. Once the roots begin to grow into the soil, it is best to ease off on the frequency of the watering but increase the amount of water applied. This will further encourage the roots to travel deeper into the soil and help establish a healthy lawn.