How Autumn Aeration Can Transform Your Lawn

23 October 2024

Farmers, gardeners and horticulturists will tell you that the best results are achieved when the groundwork is done in autumn time. Their priority at this time of year is to receive soil compaction, optimise drainage, improve soil structure, and establish next years’ cropping.

Farmers will use ploughs and cultivators to prepare the soil and relieve soil compaction, gardeners may use a spade. Lawn owners who don’t want to uproot all of their plants, will use a technique known as aeration. This article sets out to explain how autumn aeration plays a part in transforming a tired patch of grass into a verdant green lawn.

The Importance Of Soil Structure

Greenskeepers and lawn owners may not be planning to grow food, but they are aiming to cultivate strong, healthy plants with good resistance to disease, damage and drought. The secret to all of those things lies beneath the lawn, in the soil.

Soil compaction is arguably one of the most common challenges faced by lawn grasses.

Grass plants depend on their root system for the uptake of air, water and nutrients. The two main requirements for healthy root function are: enough space for the roots to grow, and the physical presence of the vital trinity of air, water and nutrients. When the soil is compacted and hard, the roots will not be able to make the most of any fertiliser and treatments added at surface level.

Soil Structure In A Nutshell

Understanding soil structure is key to creating and maintaining the lawn of your dreams. Soil is an amazing mixture of clay particles, silt, organic matter and grains of sand. It also contains billions of beneficial microscopic lifeforms and mini beasts, all of which are crucial to the health of plants and our planet.

Every single lawn will contain different proportions of these most common soil constituents as well as various minerals and plant nutrients. But all healthy soils have something in common - nothingness. Water, air and nutrients need spaces between soil particles to enable them to circulate and move to where they are needed.

In undisturbed soils worms and microbes will continually move soil particles around to maintain those spaces. But where the ground is subject to downward forces from above such as machinery, feet, or even heavy rain, their job becomes highly challenging.

How does the soil beneath your lawn become compacted?

Some soil types are more prone to compaction than others. A soil with a high clay content for example, will have lots of tiny particles which fit tightly together and don’t allow much room for air and water to circulate. A sandy soil on the other hand, has larger particles which means that the growing medium is far more difficult to compact.

The downward force from people, pets, furniture, toys, wheelbarrows and even lawn care machinery will squeeze the water and air out from between soil particles, pressing them closer together and making those inter-particle spaces smaller and tighter.

Whilst soil compaction, in the long term is not ideal it does have a positive side to it. It’s a sure sign that your lawn is being enjoyed and appreciated.

How do I know if my soil is compacted?

It’s fair to assume that most lawns will be growing on compacted soil. It’s the nature of the beast. However, a simple test will reveal the extent of that compaction. Simply rummage about in your tool box and find a screwdriver with a blade of at least 15cm long. Push the blade into the soil in your veggie patch. You would expect it to go into the ground easily with very little effort from you. Now do the same thing on your lawn. The more compacted the soil is, the more difficult it will be to push that screwdriver through it.  If you find that you need to push extra hard for the blade to penetrate the first couple of centimetres of lawn - you probably have quite a deep thatch layer too. Click here to read our article on lawn thatch.

How To Receive Soil Compaction Beneath Lawns

For soil compaction in ornamental borders or veggie beds, using a garden fork to turn over the soil and open up the structure is the perfect solution. However, this process will also uproot and kill any plants; which means, it’s not practical in a lawn-care situation unless you are planning on reseeding or re-turfing.

A garden fork is still a useful tool for receiving compaction beneath lawns though. Simply spiking the lawn with the tines will create narrow, deep holes to let air and water circulate more freely. We call that process aeration.

A more efficient way of aerating a lawn is to use a specially designed machine. Depending on the soil type, the time of year, the way a lawn is used, and individual preferences it is possible to hire a hollow tine aerator, a spike aerator or a fracture tine aerator. Read more about the different types of aerator in this article. 

By using an aerator to make small holes deep into the surface of the lawn, soil particles are encouraged to redistribute themselves, roots are given more room to grow and air and water can circulate more freely. Some types of aeration actually prune the roots too - thus stimulating more growth.

Aeration can be carried out at any time of year, providing the soil conditions are suitable. As a result of aeration, the grass plants will develop deeper, stronger root systems and be able to make better use of the nutrients in the soil. Soil microbes and mini beasts will be given a healthier environment in which to thrive. These beauties are responsible for many ecological process such as fixing nitrogen from the air, carbon sequestration, fighting plant diseases and helping to break down organic matter such as dead leaves, dead bugs and thatch.

How does autumn aeration transform a lawn?

Caring for and using the lawn at any time of year will cause soil compaction. But of course the good old British weather encourages us to spend more time outside during the spring and summer months.  Autumn aeration goes some way to rectifying any damage done to soil structure.

Believe it or not, when the visible part of your lawn is relatively inactive over the winter months, the roots beneath the surface will keep growing. They are preparing themselves to support the plants through a big growth spurt next spring. Aeration not only helps to optimise growing conditions, it can also prune the roots, encouraging them to put out even more

Aeration in autumn, also goes some way towards improving drainage over the winter months, thus reducing the risk of plant roots being damaged by waterlogging.

Finally, if you plan to overseed in autumn, scarifying and aerating your lawn will help create a more hospitable seed bed. This will support better germination and stronger young plants. In fact, if you opt for hollow tine aeration, the spaces created by removing plugs of compacted soil actually act like little plant pots. They give the newly sown seeds space, protection and a nice tilth to root into.

Regular lawn aeration really does make a visible difference to lawn health and vigour. However, it can be hard physical work - even if you do hire in specialist machinery. UKLCA members are experts in lawn care and offer cost-effective solutions to soil compaction.

Find your nearest UKLCA member here.

More information about aeration.

Autumn lawn tips from the experts.

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