7 important jobs to do in your garden this September according to the experts

With summer drawing to a close, there's much to be done in your outdoor space to get it ready for the cold months ahead

composite of someone raking, pruning and weeding
(Image credit: Getty Images)

As we bid farewell to the hazy days of summer months it's time to get prepared for the winter season ahead, which includes important September gardening jobs.

You may have already completed all your essential summer jobs earlier in the season but as the weather starts to turn there's a whole host of new tasks to be done to get your garden ready. So garden trends aside, you're going to want to get started on transforming your garden to prepare it to survive whatever winter brings.

We spoke to several gardening experts to find out what jobs they recommend getting done this month and why they're so important.

7 Jobs to get done in the garden this September

Taking steps to sort out your garden differs depending on the season you're planning on doing it in. For example in summer, say key August gardening jobs, it may entail a lot more watering and planting whereas in autumn and winter, you'll want to prioritise preparing and protecting your plants for the more aggressive weather.

Here are the seven jobs garden experts recommend you get done to give your garden the best chance of success in the new year.

1. Lawn care

grass and grass seeds

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Whether you know all the lawn care mistakes to avoid or not, ensuring your lawn remains healthy through both summer and winter can be a real challenge. This is why it's important to tend to it now before the more difficult weather arrives.

Julian Palphramand, Plant Lead at British Garden Centres says, "September is the best month to sow grass seed. The cool temperatures and fewer extreme weather conditions make it ideal for grass to establish. If your lawn needs TLC, applying feed and weed will revitalise it and prepare it for the upcoming season and winter."

He also adds that regular mowing is essential for lawn maintenance, even during autumn when the shorter days and cooler temperatures will mean less frequent moving.

"For lawns troubled by moss and weeds, it's important to address these issues before scarifying. September is also the perfect time for aeration, which involves creating small holes in the soil using a garden fork to allow better air, water, and nutrient penetration to the grassroots," he advises.

You can pick up some fast-growing grass seed from Amazon for as little as £13.99 and this one comes highly recommended.

Julian Palphramand head of plants at bristish Garden Centres
Julian Palphramand

Overseeing the procurement and selection of indoor and outdoor plant varieties for the company's 62 retail stores across the UK makes Julian an expert in sourcing the perfect plants. His expertise in horticulture and his passion for fostering a love of plants among customers help drive the continuous growth and success of the group.

2. Pruning

When it comes to pruning there are many plants you should never prune in the summer and that's because they'll benefit from it more in the colder months after August.

"In September, trim back any summer-flowering perennials that have finished blooming to promote tidiness and redirect energy to their roots. However, avoid heavy pruning of woody shrubs and trees because it may stimulate new growth that won't have enough time to harden before winter," explains Petar Ivanov, a gardening and plant expert at Fantastic Gardeners.

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Spear & Jackson Kew Gardens Woodland Collection Bypass Secateurs: RRP: £22.99 Now £16.90 at Amazon

These secateurs are made with drop-forged carbon steel for strength and feature FSC-certified ash wood handles to make deadheading with precision easy.

Peter Ivanov gardening expert
Petar Ivanov

Peter has been a gardening and plant expert at Fantastic Gardeners for over 8 years, he is now one of the company's top-performing experts and manages over 6 teams of gardeners. He works on creating stunning landscapes and prioritises sustainability in his gardening methods.

3. Deadheading

picture of woman deadheading peonies

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It's important to know how to deadhead your garden plants properly as it can have huge benefits for your garden's aesthetic and each plant's health. There are some plants you should never deadhead however those that need it will be grateful for it before the cold months.

Phoebe Carter, expert plant buyer at Cherry Lane Garden Centres says, "Autumn is the perfect time to begin tidying, deadheading as removing dead or diseased branches not only neatens your garden but also helps prevent the spread of disease. Removing these spent flowers also encourages plants to continue blooming by focusing their energy on new bulbs for the new season."

Just make sure you check whether the plant you're about to deadhead actually needs it first.

4. Dividing plants and planting

Similar to how you take a houseplant cutting, dividing your plants in your garden is known as succession planting, meaning you get more blossoms when the time comes.

Lucie Bradley from Two Wests and Elliott explains that now is a great time to start this dividing process. She says, "Throughout September (and October), divide up clumps of perennials in your garden – a great opportunity to pass on plants to friends and neighbours or spread plants around. Dividing perennial plants (every 2 or 3 years) is a great way to help plants remain healthy, as it encourages vigorous growth."

Dividing isn't the only thing you should be doing with your plants, September is also a great time to get ahead on planting certain species too. Just as there are certain vegetables to plant in August, there are some flowers that can grow through winter.

"Start arranging and planting new autumn/winter hanging baskets and containers ready for a gorgeous display of autumn colour. Look for plants that are well suited to smaller spaces and cooler temperatures such as primroses and winter heathers," adds Lucie.

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Greenman Multipurpose Hand Trowel: £15.95 at Amazon

This hand trowel really does it all, from cutting through root balls to using the fishtail tip to lift rooted weeds. There's even a twine-cutting notch that doubles up as a bottle opener, perfect for a mid-gardening beer.

5. Weeding and cleaning up

woman weeding her garden

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Knowing how to get rid of weeds is one of the most important gardening tips for keeping your garden looking its best. Unless you're opting for the rewilding trend, it's key to keep on top of weeding especially as we head into autumn.

"During this month, remove any weeds from your garden to prevent them from going to seed and causing more problems in the future," Petar advises. "Also, clean any fallen leaves and debris to prevent disease and pests from overwintering in your garden and preventing sunlight from reaching the soil."

Going around your garden and giving it a general thorough clean will make your garden spring clean next year so much easier. This also means tidying away any summer decor you've kept up that might not survive the colder weather that's on its way.

6. Fertilising and mulching

Where you might have already mastered how to water your garden plants, knowing when and how to keep them fed and fertilised can be a little more tricky.

Phoebe explains, "As your plants prepare to go dormant, their nutrient needs change. Feeding plants during the early autumn helps them build energy reserves that they tap into so they can survive the winter and come back stronger in the spring."

She does however point out that it's important to not overfeed your plants. Phoebe advises, "You shouldn’t feed them in October, so they can prepare for frost and build a form of resilience."

As for mulching, Petar recommends adding a layer around any trees, shrubs, and perennial beds to help conserve moisture and regulate soil temperature during the colder season.

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Draper Soft Grip Handle Garden Tiller: £26.25 at B&Q

Using a long-handled cultivator like this will make quick work of mulching flower beds whilst not straining your back. The soft grip handles on this particular item will ensure comfort when tackling tougher patches of dirt.

7. Protection

person covering container plants with frost protection

(Image credit: Getty Images)

As we enter autumn, you can forget to protect your plants from frost. Whether you use old towels in your garden as a frost barrier or have your own ways, you'll want to make sure your most vulnerable plants can survive the cold weather.

"The frost can be brutal on our gardens. Container plants are especially vulnerable to temperature fluctuations than those planted in the ground. As the cold air sets in these plants may need extra protection," explains Phoebe.

She adds, "If possible, move your container plants to a more sheltered location - places like a greenhouse or indoors are ideal. If this is not possible places like a south-facing wall or under an overhang, will help them to retain heat and protect them from strong winds."

FAQs

What jobs shouldn't you do in September?

Just as there are common summer gardening mistakes to avoid during the warmer months, there are some tasks you should not be doing this month.

Julian says, "While pruning deciduous trees and shrubs can be beneficial, heavy pruning in September can stimulate new growth that may not harden off before winter, making it more susceptible to frost damage."

Along with this, Julian warns against sowing tender annuals in September as these plants are particularly sensitive to frost and might not survive the winter conditions.


If you want to get even more prep done this month, Petar says you can start bulb planting for spring flowers.

"In September, you can prepare for spring by planting spring-flowering bulbs, such as tulips, daffodils, and crocuses, at the recommended depth for your region. When performing this task, remember that they will prefer a sunny location, while others may thrive better in shady areas," he explains.

Emily Smith
Digital lifestyle writer

Emily joined woman&home as a staff writer after finishing her MA in Magazine Journalism from City University in 2023. After writing various health and news content, she now specialises in lifestyle and home writing where she covers all things cleaning, interiors and homeowning.