September marks the first month of autumn. And with the weather getting cooler and damper, there’ll be plenty of things to add to your gardening checklist. It’s a great time to prepare your garden for the winter, plan for next year, and tidy up after summer.
With that said, here are 13 jobs to do in your garden this September.
Contents
- Collect seeds
- Divide herbaceous perennials
- Harvest vegetables and plant autumn/winter ones
- Plant evergreen trees and shrubs
- Dig up potatoes
- Plant spring flowering bulbs and seeds
- Harvest apples
- Give your lawn some TLC
- Keep an eye on your bird feeder
- Make your own compost
- Clean up
- Turn over soil
- Water house plants less frequently
1. Collect seeds
September is a great time to harvest ripe seeds from any summer flowering plants that you want to grow again next year. However, it’s important to only harvest seeds from flower heads when they’re hard and brown.
You might find it useful to store them in brown paper bags labelled with the name of the plant, the harvest date, and any other important information, so that they’ll be ready to sow next spring. It’s also important to make sure the seeds are completely dry before storing them. If needed, you can place them on a sheet of newspaper to dry out for a few days first.
Storing the paper bags in an airtight container will help to make sure they stay dry until they’re ready to be sown. If stored correctly, most seeds will be viable for about three years after their harvest date.
To find out more about how to collect and store seeds, check out this handy information from the RHS. The video below also provides a step-by-step guide.
2. Divide herbaceous perennials
Herbaceous perennials are plants that have non-woody stems and reach their full height and flowering potential within one year. They die over the winter months, but reappear again in spring.
As the weather gets cooler, dividing your herbaceous perennials will help them to return with even more vigour next spring.
Different perennials like to be divided in different ways at different times of the year, so it’s important to check whether September is a good time to divide yours. For example, Salvias, Helenium, Helianthus, and Japanese anemones all divide well in September.
For more tips on how and when to divide herbaceous perennials, take a look at this guide from the RHS. The video below from Waitrose will also guide you through the process.
3. Harvest vegetables and plant autumn/winter ones
Many vegetables, including peppers, sweetcorn, and courgettes, are ready to harvest in September. Check out this guide from the National Trust for information on what vegetables are best harvested in September.
September can also be the ideal time to plant some vegetables. There are plenty of hardy vegetables that you can plant now to enjoy during the winter months – and most can be sown or planted directly outside. Onions, garlic, and radishes are popular choices.
Our planting calendar includes many of the fruits and vegetables you can plant during the autumn.
4. Plant evergreen trees and shrubs
If you’ve been thinking about planting evergreen trees or shrubs, this is the month to do it. Evergreen plants are much more likely to establish themselves and survive during autumnal weather because the soil is warmer and moisture.
For best results, it can help to prepare the soil by adding some nutrient-rich compost. You can also protect young trees and shrubs from wind by attaching them to a stake or cane.
Olive trees, fig trees, and Japanese Quince are a few good options to consider.
5. Dig up potatoes
Slugs become far more active during the autumn – which can put your potatoes at risk.
To prevent them being eaten by slugs, aim to dig them up around mid-September, by which time they’re usually ready. For more information on how and when to dig up potatoes, check out this helpful guide from Gardening Know How.
Potatoes grown outdoors will also be more susceptible to blight (a fungal disease). For guidance on treating and preventing blight, have a read of this article from Garden Focused.
Top tip: Some types of potatoes are more susceptible to slugs than others. If your soil is popular with slugs, it’s best to avoid Maris Piper, Marfona, and Estima potato varieties. Instead, opt for Romano, Lady Rosetta, or Pentland Dell.
Wilia, Heather, or Kestrel varieties can also make good options as they mature early so can be lifted during August.
6. Plant spring-flowering bulbs and seeds
If you want flowering plants in your garden next spring, you’ll need to plant seeds and bulbs this autumn so they can start putting down roots. Make sure you choose bulbs that are firm, plump, and free from mould.
If you’d like to buy some seeds, Dobies has a great selection that you can plant in September. English Marigolds, poppies, and cornflowers can be sown earlier in the month, while daffodils, crocus, and hyacinths are best planted towards the end of September.
7. Harvest apples
September marks the beginning of apple-picking season, so get ready to make some room in your fruit bowl. You’ll know whether apples are ready to pick because they’ll come away easily with a gentle twist.
Try to harvest apples before they fall to the ground and start rotting or become a tasty treat for wildlife. If any apples do fall but only have minimal damage, try cutting off the bad bits and using the rest in something like a crumble or strudel. Delicious Magazine has a huge selection of apple recipes if you’d like inspiration.
To learn what other fruits are ready to harvest around September, check out our article; What fruit and vegetables are in season now?
8. Give your lawn some TLC
September can be an ideal time to work on your lawn because the weather is usually mild and there’s an increase in rainfall – which can help grass reach its full potential.
Towards the end of summer, it’s not uncommon for lawns to be filled with moss or weeds. This is often because they’re lacking in nutrients. But, luckily, there are a few things you can do to help. These include…
- Use a rake to remove any moss or thatch (old grass clippings) that have built up on your lawn and pull out any large weeds by hand.
- Continue to mow your grass regularly while it’s growing (as long as it’s not too muddy). September can be a dewy month, so it’s best to cut your grass during the day to get a straight cut and to avoid your lawnmower becoming clogged with wet grass clippings.
- Aerate your lawn to improve drainage. You can do this by making some evenly spaced holes with a garden fork.
- Add fertiliser to your lawn. Feeding your lawn during the autumn will encourage strong root growth, help it stay green and healthy, and protect it from frost and disease during the winter months.
You can buy lawn fertiliser on Amazon. All you’ll need to do is mix the recommended amount of feed with some water, and apply it evenly over your grass.
9. Keep an eye on your bird feeder
With the changing seasons comes a change in wildlife. For this reason, it’s worth keeping a close eye on your bird feeder.
Some bird species will be eating as much as they can to prepare for hibernation, some will be fuelling up for a long flight, while others will simply be stocking up for a cold and unpredictable winter.
Once you’ve established a feeding routine, try to stick to it, as birds will become used to it and visit your garden regularly looking for their next meal. The RSPB have some useful tips on what to feed birds and how to keep your feeding station hygienic and pest-free.
During the autumn, we say goodbye to birds that have been visiting for the summer – including the Willow Warbler. These tiny birds mostly eat fruit and insects during the summer, so they don’t visit feeders often. But you might see an appearance during the autumn when they start stocking up on nuts and berries to prepare for their 5,000-mile journey back to sub-Saharan Africa.
Once Willow Warblers and other summer visitors have left for the winter, we receive a whole new flurry of bird species who come from much colder regions, including Scandinavia and Russia. These birds include the Redwing, Waxwing, and Fieldfare.
If you’re interested in birds, you might like to read our articles; A beginner’s guide to birdwatching and 11 ways to make your garden more wildlife friendly.
10. Make your own compost
It takes about six months to make your own compost, which makes autumn a great time to get started because it’ll hopefully be ready for spring planting. Making your own compost allows you to be in control of what’s in it and avoid any nasty chemicals. Plus, you’ll save money and be able to recycle garden and kitchen waste.
To get started, you’ll need a compost bin. It’s possible to make compost on bare earth, but this can take much longer than in a bin. Bins are helpful because they retain warmth and moisture, which speeds up the composting process. You can make your own compost bin or pick one up from your local garden centre, Homebase, or B&Q.
Then, fill your compost bin with as much organic waste as possible (the more varied the ingredients, the richer your compost will be) and leave it to rot. You can add things like teabags, egg shells, leaves, and grass clippings.
However, there are also things that you shouldn’t add to your compost, like meat fat, dairy, and bones. To find out more about what to put in your compost bin, Gardening Know How has some useful guidance. The video below also offers some helpful tips.
11. Clean up
Having a tidy, well-tended garden during the cooler months can help lift spirits and mean you’re ready to welcome spring when it finally comes. And after a long summer, there’s usually plenty that you can do to clean up.
This might include…
Washing your BBQ and garden furniture with some soapy water and either putting them away or covering them with tarpaulin to keep rust and moss at bay.
Cleaning out empty pots and hanging baskets that are past their best and preparing them for spring or autumn/winter flowering bulbs.
Cleaning out birdbaths and keeping them topped up.
Cleaning out greenhouses and water butts so that they’re ready to be used this autumn.
12. Turn over soil
Soil usually works hard during the summer months – going through many cycles of being watered and then drying out.
This can sometimes cause it to become compacted and prevent water being absorbed fully and plant roots from receiving enough oxygen. It also means that the soil will have less microbiological activity, which is important for feeding plants and protecting them from diseases.
Turning over your soil and mixing some compost into it will aerate it, mix up the nutrients, and improve the growing conditions. The video below will show you how to prepare and improve your soil.
13. Water houseplants less frequently
Many houseplants need time to dry out in between watering so that air can get into the soil and roots can breathe properly. Soil that’s constantly damp will also be prone to root rot and overwatered plants may change colour and start to wilt.
In September, houseplants will be receiving less sunlight and therefore absorb water at a slower rate. For this reason, you probably won’t need to water them as frequently.
For tips on buying plants that are easy to care for, you might be interested in our articles; 10 low-maintenance indoor plants that can add life to your home and 10 flowering houseplants to brighten up your home.
Final thoughts...
While many see the end of summer as the end of the gardening season, you don’t have to pack up your trough and head inside just yet. From planting evergreen trees and shrubs to making your own compost, there’s plenty still to do in September for those with green fingers.
For further reading, head over to the gardening section of our website. Here, you’ll find tips on everything from gardening in small spaces to cheap and easy garden design ideas.
Do you have any additional September gardening tips that you’d like to share? We’d love to hear from you in the comments below.