Gardening tips for September
September marks the beginning of autumn, but there’s still plenty to enjoy in the garden. The days are getting slightly shorter, and the weather a little cooler, but the soil is still warm from summer and there’s plenty you can do to keep your garden look its best.
Now’s the time to plant spring-flowering bulbs, give your lawn some attention after the summer (depending on how the heatwave has affected the grass), and start preparing your garden for the season ahead.
There’s lots to harvest from the vegetable patch and fruit garden too, while cooler temperatures make September a great time to plant new trees, shrubs, and perennials.
What can I do in my garden in September?
September is all about getting your garden ready for autumn while making the most of the last of the summer colour.
Keep deadheading summer-flowering plants such as dahlias and roses to encourage them to flower for as long as possible. You can also continue watering and feeding plants in containers while the weather remains dry.
As summer bedding starts to fade, replace it with autumn and winter favourites such as pansies, violas, cyclamen and wallflowers. These will provide colour through the cooler months.
Keep an eye on newly planted plants and containers and water them during dry spells. Watering at the base of plants in the early morning or evening can help reduce water loss, and collected rainwater is a good option where available.
Divide established herbaceous perennials that have become overcrowded. September is a good time to do this while the plants are beginning to slow down after their summer growth.
Collect seeds from your favourite plants once they have dried and store them somewhere cool and dry. It’s an easy way to grow more plants in your garden next year.
Start clearing fallen leaves as they appear, particularly from lawns, paths and patios. Add healthy leaves to your compost or use them to make leaf mould for a useful soil improver.
Spring-flowering bulbs are now available, with plenty of varieties to choose from, including classic favourites such as daffodils, crocuses, narcissi and hyacinths. Planting bulbs in September gives them time to establish their roots before winter.
Tulips are generally best planted later in autumn, particularly from October into November, so you have plenty of time to plan your display.
Prepared hyacinths can be planted indoors in September for flowers around Christmas. Choose a suitable pot or bowl and follow the instructions on the bulb packaging.
How to look after your lawn this autumn
After a summer of heat, dry weather and increased garden use, your lawn may be looking a little worse for wear. If your grass has turned brown during a heatwave or drought, don’t worry, it may not be dead. Established grass can go dormant during prolonged dry weather and should start to green up again when cooler temperatures and autumn rainfall return.
September is a good time to help your lawn recover and repair any areas that have genuinely died back.
If your lawn has simply turned brown during a dry spell, resist the temptation to use large amounts of water to bring it back to life. Established lawns are surprisingly resilient and should recover naturally when rainfall returns. This is particularly important if you live in an area affected by a hosepipe ban.
If areas remain completely bare after the weather becomes cooler and wetter, these may need repairing. Rake away dead grass and debris, loosen the soil and add a little lawn dressing or topsoil before reseeding with a suitable lawn seed. September is an ideal time for this while the soil is still warm.
Scarify your lawn to remove moss, thatch and dead grass that have built up over summer. This allows air and water to reach the soil more easily and can help the lawn cope better with future dry weather.
Apply an autumn lawn feed if your lawn needs a boost. Choose a feed specifically formulated for autumn rather than using leftover summer lawn feed. Autumn feeds are designed to support healthy roots rather than encouraging lots of soft, leafy growth. If your lawn has been severely affected by drought, however, wait until it has recovered before feeding.
Keep mowing, but don't cut too short. As temperatures fall, grass growth will slow down, so you won't need to mow as frequently. Raise your mower's cutting height slightly and avoid cutting drought-stressed grass too closely, as this can put it under further stress.
September is also an excellent time to create a new lawn. Sow grass seed onto prepared soil when it is moist after rainfall, or lay turf while the ground is damp but not waterlogged. New grass will have the autumn months to establish before winter.
If your lawn has survived the summer but looks a little tired, don't be tempted to replace it straight away. A combination of autumn rain, cooler temperatures, and a little maintenance can make a big difference, and many lawns will recover naturally.
What fruit and veg can I grow in September?
There’s still plenty to harvest from your vegetable patch in September, but you can also sow crops that will provide fresh leaves and vegetables through autumn and winter.
Harvest onions, garlic, and shallots once the foliage starts to yellow and fall over. Allow them to dry somewhere cool and well-ventilated before storing.
Keep picking courgettes while they are young and tender to encourage the plants to keep producing.
Give tomatoes as much sunlight as possible to help the last fruits ripen. Remove some foliage around the fruit if necessary to improve light and airflow.
Continue harvesting apples, pears, plums and autumn-fruiting raspberries as they ripen. A ripe apple should come away easily when gently lifted and twisted.
Sow winter salads, spinach, rocket, and other hardy salad leaves for autumn and winter picking. September is also a good time to plant overwintering onion sets.
If you have leafy crops growing, protect them with netting to stop birds from damaging the leaves.
Plant new strawberry plants or runners now for fruit next summer.
When planting anything new, make sure you prepare the soil well and water it thoroughly. Continue checking newly planted trees, shrubs and perennials during dry spells.
Preparing your garden for autumn
As the weather changes, a little preparation now can make the next few months easier.
Bring tender plants and summer bedding into a greenhouse, conservatory, or sheltered space if frost is forecast. Keep an eye on overnight temperatures, particularly towards the end of the month.
Clean out greenhouses and cold frames ready for autumn use, removing old plant debris and giving the glass a good clean to maximise the available light.
Check plant supports, ties, and stakes before autumn winds arrive, particularly around young trees and taller plants.
Give your garden tools a clean and dry after use, then store them somewhere sheltered. It’s also a good opportunity to check that your secateurs, shears and other tools are sharp and ready for autumn pruning.
Keep composting healthy garden waste, including grass clippings and fallen leaves. Avoid adding diseased plant material to your compost heap.
We would love to see what tasks and projects you’ve been up to in the garden so make sure to tag us @dobbiesgardencentres so we can see all your gorgeous gardens!