Tips and advice on garden care in September
The summer holidays are over, the kids are back to school and the growing season is coming to a close.
Thankfully, there's still plenty of colour to be enjoyed in your garden from summer borders, And if the weather is mild, some summer plants and crops could continue for another month or more. So before the warm days are gone for another year, get outside and make the most of all the good work you’ve done in your garden over the last few months.
Tools & materials required
Gardening ideas for September
Tools you might need:
Get your lawn ready for winter
Now’s the time to carry out your lawn maintenance to prepare it for the colder months ahead. First, mow the lawn before raking out any moss and weeds. Use a traditional lawn rake, or for larger areas we recommend a powered lawn raker to make easier work of it. Then mow the lawn again - this time at right angles to how you did it last time (as if you were trying to make a grid). This ensures that you cut off all the creeping grasses and weeds that have been raised by raking.
Next, aerate your lawn by spiking it all over. This helps to alleviate areas of compacted soil and improves drainage before the heavy autumnal rainfall arrives. Use either a garden fork, pushing it down about 8 to 10 centimetres (cm) into the surface of the lawn, or an aerator which is designed for this task.
Finish up by feeding the grass with a good autumn formula lawn feed. Be sure to buy the right feed for the time of year – any leftover spring lawn feed isn’t suitable and may do more harm than good.
Plant winter bedding and spring-flowering bulbs
As soon as summer bedding plants stop producing flowers, remove them from beds, borders, hanging baskets and containers. Once you’ve created a space you can prepare to plant up winter bedding. We love the striking colour of winter-flowering pansies – especially the bicoloured varieties. Fork over the beds, working in some compost or well-rotted manure and add a little fertiliser (following the instructions on the container), before adding winter bedding into the gaps.
Make sure the plants are kept well watered while they find their feet. We recommend adding mulch (bark chippings) to the surface of beds and borders to help new plants survive over winter. It's great for supressing weeds, retaining moisture during dry spells, insulating against cold temperatures and protecting any root systems or crowns that may be vulnerable.
Now's also the time to get planting your spring-flowering bulbs, like hyacinths, tulips and bluebells, for maximum impact come March. When selecting bulbs, pay attention to their size - the larger the bulb, the larger and taller the flowers. Also look for firm, hard flesh with a dry skin. And if the bulb is beginning to sprout, check that the young shoots are white or green.
To find out more, read our advice on planting spring-flowering bulbs.
Clear fallen leaves
Don’t delay clearing leaves until the end of autumn – if left on your lawn for long periods, they'll reduce the amount of light that reaches the grass and make it turn yellow. Avoid this by clearing the leaves frequently, a little at a time.
A lawn rake is fine for large, flat areas of lawn but impractical for borders, so consider investing in a garden vacuum. If you use it on shredder mode, the leaves will rot down much more quickly when composted – add them to your compost bin in thin layers along with other organic matter.
For more on which garden vacuum or blower to buy, check out our helpful buyer's guide.
Support your trees and climbers
Autumn brings strong winds, so newly-planted trees will need to be staked. This will prevent rocking damage, which can uplift and destroy their root anchorage, or even cause them to snap. Instead of using a single, vertical stake, use an angled one which will allow the tree to move in the breeze instead of staying totally rigid – swaying is proven to promote trunk growth.
In very windy, or exposed areas, use a double stake. Two stakes are hammered into the ground, side by side, and one or two horizontal braces are then screwed to them. Then tie the tree to the braces.
Climbers, clematis and climbing roses will all need some kind of frame to grow up when they start to put on new growth in the spring, and it’s often easier to put the structure in now, as they've reached the end of their growing season. Frames comes in different shapes, which define the direction that your plants grow in:
- Trellises can be attached to fencing or the sides of structures so that your climbers can spread outwards and upwards.
- A series of climbing wires can be a more flexible option than trellis – it can be added to, and expanded, as your plant grows.
- Obelisks are freestanding, tapered pillars that encourage your plants to grow upwards.
- Arches allow your plants to grow up and over a pathway, or entrance to another area of your garden.
Putting these structures in place now will save a struggle come spring.
Bring in the autumn harvest
September is the time to harvest:
- Maincrop potatoes
- Onions and shallots
- French and runner beans
- Lettuce, rocket, spring onions and other late salad crops
- Baby leaf and perpetual spinach
- Autumn cauliflower and cabbages
- Baby leeks
Late crops of salads, courgettes or any other plants that are still in the ground should be covered with cloches or horticultural fleece. And leave tomatoes on the plants until the end of the month – then pick all remaining fruit and bring them indoors to ripen on a windowsill.
When it comes to fruit, you can start picking blackberries and the first autumn-fruiting raspberries, as well as tree fruits like apples and Conference pears (these will be ready towards the end of the month). Be sure to harvest these as they ripen. To find out if apples and pears are ready to be picked, gently twist a fruit growing on the tree. If the fruit comes away easily, it's ready.