September is one of the best months to rescue a struggling lawn – here's what you should do for healthier grass

If you are wondering what to do with your lawn in September, you're not alone. Plenty of us have been eyeing our distressed grass nervously from our windows, uncertain what we can do (if anything) to get it looking its verdant best again.

Brown patches, thinning grass and compacted soil are all common after prolonged dry weather, but there really is no need to panic; grass usually bounces back. Still, while September is traditionally one of the busiest months in the lawn care calendar, experts say this year calls for a slightly different approach.

From knowing when to mow to deciding whether your lawn really needs feeding, here's what the experts recommend doing this month...

What to do with your lawn in September

According to Morris Hankinson, Managing Director of Hopes Grove Nurseries, many brown lawns aren't actually dead – they're simply dormant after weeks of drought.

'After this year's drought and prolonged dry weather across the UK, the usual September lawn care routine may not be the same as in previous years.

Morris Hankinson

Morris Hankinson is the founder and managing director of Hopes Grove Nurseries Ltd, the UK’s only specialist grower-retailer of hedging plants. He established the thriving business in 1992, shortly after graduating with a Commercial Horticulture Degree from Writtle College, Essex.

'Grass usually goes into dormancy throughout drought conditions and will green up again when rain arrives,' he adds. 'Instead of watering a brown lawn, wait for cooler weather and a good amount of rain so the soil softens before getting to work on any major lawn work.'

So, while it can be tempting to reach for the hose, try to keep in mind that established lawns are remarkably resilient and often recover naturally once rainfall returns.

That being said, there are a few tangible things you can do to help...

1. Raise your mower blades

The first thing to do with your lawn in September is more of a what not to do: if your grass is still growing, avoid giving it a close cut. 'Make sure the blades on your mower are higher than you would usually have during summer and only trim infrequently,' says Morris.

'Longer grass will help protect the soil and ultimately make the lawn more resilient in dry conditions. If growth has stopped completely, there's no need to mow at all.'

Peter Chaloner, managing director at Cobra Garden, agrees that mowing should continue only while the lawn is actively growing. 'Avoid cutting it excessively short,' he adds.

'As we move further into autumn, growth will slow naturally, so the frequency of mowing can be reduced gradually.'

2. Aerate compacted soil

Once autumn rain has softened the ground, September is the perfect opportunity to aerate your lawn. 'Simply use a garden fork or aerator tool (like this one from Walansee, £35.99 on Amazon) to make holes in the lawn. This allows air, water and nutrients to reach the roots of the grass,' promises Morris.

'Aerating is helpful after a dry summer because compacted soil prevents rain from soaking deeper into the roots.'

Pater agrees, noting that aeration is especially worthwhile if your lawn has seen plenty of foot traffic over the summer. 'It creates channels through the soil and helps to relieve any compaction,' he notes.

For a smaller lawn, Peter says that 'a garden fork can be perfectly adequate, while more heavily compacted or larger areas may benefit from hollow-tine aeration from an aerator'.

3. Repair bare patches and overseed

September is widely considered one of the best months for sowing grass seed, but timing is crucial after a dry summer.

'While the soil is warm enough for seeds to germinate and the weather is cooler and wetter, don't sow seed into baked, dry soil, though, because the seed will struggle to germinate,' says Morris. 'Wait until rain has softened the soil and there is more rain to come so the soil stays moist.'

He adds that if you have suffered from extremely dry, scorched grass, you must make sure the new seed is a drought-tolerant mix, like Miracle-Gro's Professional Super drought-tolerant mix, £13.43 on Amazon.

Matt J Adams, founder and lead gardener at The Relentless Gardener, agrees that choosing the right seed is incredibly important.

'Overseeding can repair thin or damaged areas, with warm soil and increased autumn moisture creating ideal conditions for germination, but take care to choose a seed mix suited to your lawn, whether hard-wearing, ornamental with a fescue-heavy mix, shady or general-purpose with a mix containing perennial ryegrass and fescues.'

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4. Feed carefully

Autumn is often associated with lawn feeding, but after a particularly dry summer, not every lawn will benefit.

Morris says: 'At this time of year, feeding is often recommended, but this year's drought means it might not be a good idea. If you have a baked lawn, the RHS recommends avoiding fertiliser on drought-affected turf in autumn and delaying treatment until spring if necessary.'

If your lawn is healthy and has recovered from the drought, Matt says that an autumn-specific feed can help strengthen it before winter.

'A good autumn lawn feed helps prepare the grass for the months ahead by supporting the roots and improving the lawn's ability to cope with winter. Use a feed designed specifically for autumn rather than continuing with a high-nitrogen summer fertiliser.'

'You want to encourage healthy roots and winter resilience, not force lots of soft, leafy growth at the wrong time of year,' he adds.

5. Scarify

September is also a good time to tackle thatch and improve your soil before wetter weather arrives, which is why Peter recommends scarifying to remove built-up moss and dead material.

'One of the most beneficial jobs to consider is scarifying. Over time, a layer of dead grass, moss, leaves and other organic material can build up as thatch at the base of the lawn,' he says, noting that this can prevent water, air and nutrients from properly reaching the soil and grass roots.

'Scarifying involves using a rake, or powered scarifier, like the Vonhaus lawn aerator and scarifier, £99.99 at Amazon, to remove this unwanted material from the lawn. While it can look quite aggressive and may leave the grass appearing thin or patchy initially, it helps clear the way for the healthier grass beneath to thrive,' he promises.

By reducing thatch and moss, scarifying can improve airflow around the base of the grass and allow moisture and nutrients to penetrate the soil more effectively.'

6. Top dress where needed

Matt recommends applying a top dressing after mowing and aerating to improve drainage and help reduce moss over winter.

'Applying a 70/30 top dressing – a mix of sand and soil – can help to prevent waterlogging and create less favourable conditions for moss,' he says, noting that you should 'apply after mowing and, where needed, scarifying and aerating, working it gently into the lawn without smothering the grass'.

FAQs

Rather than trying to transform your lawn in a single weekend, Matt says September should be about laying the foundations for healthier grass next year.

'The key September rule? Don't chase perfection overnight. Focus on healthy roots, appropriate nutrition and good soil conditions for a stronger lawn next spring.'

Sounds like a plan to us!