Caring for a Waterlogged Lawn

Caring for a Waterlogged Lawn

Ever wondered how to care for your lawn after a flood or heavy rain? You've got waterlogged soil and wet roots, not to mention poor drainage leading to excess water. Unless you're a fan of a bog garden, you don't want a soil surface that's soaking wet.

A waterlogged lawn is a gardener's worst nightmare – it means less oxygen in the soil and compacted soil particles. You'll need to fix it ASAP so your plants don't get root rot and drown. Start by letting the water drain, then choose one of the waterlogging solutions.

Got squelchy soil in your garden? Don't panic! Here's how to fix a waterlogged lawn, easy-peasy.

What is 'waterlogging'?

You have a waterlogged lawn if water sits on the soil surface, either not draining or draining very slowly. Healthy soil does retain moisture, but not to the point of sogginess or minor flooding.

Why is waterlogged soil bad?

If garden plants remain submerged in water for prolonged periods, it can prove fatal for plant roots. Waterlogged lawns can cause root rot, since roots cannot access oxygen. When that happens, your plants begin to drown because they cannot access vital nutrients.

How to spot waterlogged soil

In the gardening world, there's a difference between a moist lawn and a waterlogged lawn. Look out for the following to tell if your garden is waterlogged:

  • Muddy puddles or sticky soil surfaces
  • Squelching under foot traffic
  • Plants turn yellow
  • An appearance like a swamp
  • Dead patches
  • Moss and other similar organic matter
  • Weeds

If you've noticed any of these symptoms on your lawn, you should avoid walking or any heavy foot traffic – that'll compact the soil particles, leading to even less air under the ground.

Causes of a waterlogged lawn

Sometimes this is due to soil type; dense, heavily compacted, or ill-drained soils (such as clay) tend to retain water more easily. Other times, natural phenomena such as heavy rainfall or flooding can overwhelm your garden's drainage system, causing excess water.

A poor root system can also cause waterlogging. Thick, well-developed plants and grass roots absorb more water, so that water doesn't accumulate.

Fixing a waterlogged lawn

Before anything else, step one is to wait for the water to drain. Avoid walking around the area since this can make things worse. Following that, depending on how waterlogged your lawn is – or how much effort you're willing to put in – choose one of the following solutions for waterlogged lawns.

Spiking the soil surfaces

Spiking aerates soil, helping improve drainage and letting air reach the root system. It's also sometimes called aeration, pricking, or slitting. Spiking is a simple process, but will require different equipment depending on the severity of the soakage.

  • Light waterlogging – Use a garden fork
  • Moderate waterlogging – Garden fork or aerator shoes
  • Severe waterlogging – Hollow tine aerator

Start by draining away all excess water so the soil is as dry as you can get it. A garden fork or pair of aerator shoes can prick up to 2.0–3.0cm in depth. If that isn't enough, a hollow tine aerator can reach up to 15.0cm deep.

Fill holes with horticultural sharp sand to guide water flow. Don't put too many holes, though, or you'll take out too much earth!

Ground replacement

If your soil type contains too much heavy clay, this causes it to retain more water. No amount of spiking will help in the long run since your garden will simply continue retaining too much moisture.

It may sound radical, but you may have to replace your entire lawn with fresh soil that contains free-draining material. Start with a 5.0cm layer of sharp sand, then follow with some topsoil (ideally loamy soil for good drainage). You can mix in some mulch for added moisture retention. Then add a fresh layer of turf.

This may end up giving you a thicker lawn, but that adds to better drainage and helps minimise waterlogging.

Backyard drainage system

You can create a drainage system in your lawn to collect rainwater and transport it away from key areas. Choose the lowest point of your yard and dig a trench, about 0.5–1.0m deep. Cover it with landscaping fabric and fill it with gravel. You can also use a half-pipe to guide water away from your garden.

TIP: Check local regulations before building a drain system in your garden!

Moss killer

Over-moist soil lets moss thrive, and this can suffocate your lawn. Moss also soaks up water, leading to damp conditions. Use moss killer so the organic matter doesn't take over your garden. You can also overseed grass to deter moss from growing.

Lawn cultivation

When it comes to compacted soil, cultivation is a crucial component. Compost or mulch will improve your soil structure and foundation. Mix in compost or mulch with your topsoil to fix its composition – the more clay, the more compost.

Make a bog garden

Certain plants actually like being soaked in water, and will help in absorbing excess moisture in the soil. You can create a bog garden to help and add a nice, tropical aesthetic. Some plants include:

  • Amsonia
  • Astrantia
  • Cardamine
  • Geraniums
  • Persicaria

Double-check with qualified gardeners on how to start a bog garden correctly!