When it comes to deciding when to aerate a lawn, it's true to say that timing is everything if you want to get the best results.
As we'll go on to explain in more detail, early autumn is a prime time to complete this task for a number of reasons. Doing it at this time of year will give your lawn a real boost by letting in more air for healthier roots, improving drainage to avoid waterlogging issues, and resulting in faster uptake of nutrients.
So if your patch of grass doesn't measure up and you can see compacted areas of thin or bare grass, or your lawn is covered in weeds, knowing how to aerate a lawn as well as the best time to do it is a great first step in getting your grass back to its best, as our experts explain.
When is the best time to aerate a lawn?
In basic terms, aerating involves piercing multiple holes in your lawn to boost the circulation of air and improve drainage.
“Aerating is one of the most valuable lawn care tasks, but many homeowners are unsure when to do it,” says Jonathan Davis, lawncare expert at Lawnsmith. “Aerate when the grass is growing strongly and the soil is slightly moist. For most UK lawns, the prime window is mid-September to late October, when the summer stress on your lawn has eased, the soil still holds warmth, and recovery is fast."
If you miss out on aerating a lawn during your autumn lawn care, a reliable second window is mid-March to late April, once growth restarts and the ground is workable, advises Jonathan. The soil is also likely to be moist in spring too. You may want to consider overseeding a lawn at this time of year too.
As for the wrong time of year to aerate a lawn? If you aerate a lawn in the summer when the ground is sunbaked it will still reduce compaction but may not necessarily be so beneficial to the growth of the roots, especially if the weather is dry as the roots need water to thrive. It’s best to avoid aerating in winter too, as the grass growth slows right down and recovery will be poor.
Jonathan Davis is the Lawn Care Expert at Lawnsmith, where he shares advice to help homeowners enjoy greener, healthier lawns. Passionate about the idea that a lawn should be both beautiful and practical, Jonathan champions lawns as spaces for play, summer barbecues, and everyday enjoyment.
Shop these handy lawn aerating tools
This rolling lawn aerator lets air, water and nutrients reach grass roots for a greener, more beautiful lawn. The sturdy wheels roll easily over any turf, and its metal spikes aerate the lawn deeply.
These super stable aeration 'shoes' with metal spikes fit easily over your own boots or shoes, and have adjustable fasteners to get the right fit. This set comes with a handy stainless-steel shovel too.
This five-prong lawn aerator has an epoxy-coated head for improved resistance to rust, scratches, humidity and alkalis in the soil. Use it to reduce compaction in the soil and improve drainage.
Why timing is so crucial for lawn aeration
Choose the right timing in your lawn care calendar is key as it will ensure your lawn bounces back quickly, grows stronger and stays healthy all year round.
“These timings matter because aeration is a controlled disturbance,” explains Jonathan Davis. “You are creating thousands of small channels that relieve compaction, allowing air, water and nutrients to reach the roots.
"If you aerate while the lawn is actively growing, roots can quickly occupy these channels, the sward [the technical term for an expanse of short grass] thickens, and resilience improves before the next bout of weather.”
During winter, however, grass recovery is much slower, and aeration can invite lawn weeds or moss growth. Meanwhile in periods of summer drought, the grass is already under stress, and aeration can set it back.
Assess the soil and weather conditions
If you're mulling over when to aerate a lawn one of the best pieces of advice you can take on board is to work with the weather.
"Choose a day after steady rain, or water the evening before so the soil is pliable rather than baked hard or waterlogged," advises Jonathan Davis. "Avoid frozen or saturated conditions from December through to February, and steer clear of aerating in heatwaves in July and August too.” Stressing your lawn by carrying out too many maintenance tasks in hot weather is a common summer lawn care mistake.
As a general rule, according to Jonathan, UK lawns respond well to aeration when soil temperatures are consistently above 8 to 10 degrees in spring and autumn. "Heavy clay and high-traffic lawns benefit from annual aeration, while lighter soils may only require it once a year, either in autumn or spring."
Time aeration well and your lawn will benefit from deeper roots, better winter drainage and stronger growth for the following season.
Clues it's the right time to aerate your lawn
After a long summer of use and heavy traffic across it leading to soil compaction your grass can die. Aeration works as a renewal process that will help rejuvenate your lawn and get it back to its best. If the soil has become compacted aerating will help loosen the soil so that new grass can grow.
"If you find that you’re getting areas of water pooling on the lawn after rainfall, or the lawn is becoming boggy this is usually a sign to aerate," says lawn care specialist Chrissie Handley from Online Turf. "Water will be struggling to drain from the lawn due to the compacted soil, so encouraging airflow and improving drainage will help keep your lawn nice and healthy."
The best time to aerate a lawn is when the soil is 'malleable'. This is when temperatures are mild and ideally slightly moist. "You can’t aerate a frozen winter lawn, or a super dry lawn in a heatwave as the ground will be too stiff and unworkable," explains Chrissie.
"The rule is to spike only when compaction is obvious," says lawn expert David Hessayon, author of the best-selling book The Lawn Expert, available at Amazon. "Do the work in early autumn, and carry it out once a year if you use a garden fork and no more than once every three years if you use a hollow tine fork."
Chrissie Handley is a lawn care specialist working for Online Turf. With extensive expertise in turf-laying, grass maintenance and seasonal gardening advice, she is dedicated to helping gardening enthusiasts achieve lush, healthy lawns year-round.
Adding lawn aerating to your list of September garden jobs will help you keep on top of your lawn care and ensure it's in the best possible condition before the worst of the winter weather arrives.
It's also best to aerate before planting bulbs in a lawn, but be sure to give your turf time to settle before getting the dibber out.
