Waterlogged Winter Lawn?

If your lawn becomes soggy and boggy during the winter season, you’ve no doubt noticed it’s prone to damage. It’s pretty standard for well-worn routes on the lawn to become muddy and highly visible.

What you may not know, is that repeated foot traffic on lawn grass can cause long-term damage to soil structure, through compaction. The effects of that damage can keep unfolding long after the lawn has dried out!

So, we’ll give you a quick explanation of what happens to a compacted lawn, followed by our tips to fix it.

If you can possibly avoid it, it’s best not to walk on a waterlogged lawn at all. Putting weight on saturated soil compresses the soil particles and contributes to compaction. This is why running a vehicle on a lawn is a big no-no. Under the weight of a car, tyres can compress soft soil to form deep ruts, where grass will struggle to regrow. On top of being deeply unattractive, wheel ruts are also infuriatingly difficult to mow.

The biggest problem with compaction is that it prevents oxygen, water and nutrients entering the soil. The beneficial microbes in your lawn soil need all these elements to survive. Because soil microbes are the main providers of nutrients for grass, allowing plenty of oxygen and nutrients to circulate around the root zone is essential for a healthy lawn.

The texture of different types of soil is due to the size of the individual particles. When trillions of soil particles are stacked up on top of each other they have gaps, called pore spaces, in between them. These are the gaps that allow water, oxygen, plant nutrients and microbial life to travel freely through the soil.

The size of the pore spaces determines how efficiently soil drains or retains moisture. Very sandy soil has large pore spaces, so it drains freely. Heavy clay has ultra-fine particles and tiny pore spaces that impede the passage of water, so clay only absorbs a certain amount of moisture until it becomes saturated. When clay is waterlogged, it’s unable to absorb more water or drain effectively.

When soil becomes saturated with water, oxygen is excluded. With very little oxygen circulating to grass roots, growth can be dramatically restricted. On top of that, an anaerobic environment really doesn't suit beneficial soil microbes, so grass plants struggle even more without their symbiotic little friends to manufacture food for them.

As you can see, waterlogged soil is a challenging enough environment for lawn grass already; the effects become far worse when the soil is squeezed and compacted.

How to Tackle the Problem

• For areas of lawn you can’t avoid walking on, consider putting down a row of pavers to step on. Your lawn will look much better!

• Applying gypsum as a soil conditioner is an effective way to improve clay soil. This helps break up the clay, improves drainage and boosts your soil’s ability to breathe. You can also use garden lime to break up clay soil, but gypsum has a big advantage over lime; gypsum is pH-neutral, meaning it won't significantly alter the soil's acidity or alkalinity.

• Yates Gypsum Clay Breaker Soil Improver Granules contains a blend of gypsum, zeolite, lime and molasses that's designed to help break up heavy clay. The granules are easy to apply and much less messy and dusty than traditional powdered gypsum. Apply gypsum at a rate of 260g per square metre. Ensure you rake it into the topsoil and water it in well.

• A simple method to aerate lawn soil is to use a garden fork. Simply push the fork down to about 10cm depth and give it a good wriggle back and forth to widen the holes. Work your way around the whole lawn, making rows of holes, spaced about 10-15cm apart. This is quite hard work, so it’s more suitable for small lawns.

• For very heavily compacted soils, coring is a great remedy. This can be done by a hiring a coring machine, which cuts multitudes of small soil ‘plugs’ out of the lawn and dumps them on the surface. While it can look a little unsightly at first, after a couple of mows, your lawn will thank you for it!

• For lawns that stay soggy throughout winter, consider putting in a French drain. It requires a lot of digging, but it really improves the health and resilience of your lawn and makes it much easier to care for over the long term. A French drain works by re-directing surface water and groundwater away from wet areas, to allow lawn soil to drain and dry quickly after heavy rain.