Gardening in September: everything you still need to do this month

bright blossoming tricolor pansy garden
Gardening in September: to-do listyumehana - Getty Images

Gardening in September: While you enjoy the vibrant colours in the garden, this is a significant month to harvest, prepare for autumn, and care for the lawn.


• September and October are the perfect months to divide clumps of perennials. If you see any gaps, look in your local nursery for autumn-flowering plants such as asters and rudbeckias, to give one last blast of colour before the frosts.

• It's still worth deadheading dahlias, roses and even sweet peas to keep them flowering for another few weeks.

Rose cuttings

Have a go at taking rose cuttings – it isn't as difficult or time-consuming as you might think.

1. Look for long, healthy stems and cut off about 30cm just below a leaf node with a straight cut.

2. Now take off the thorns and any leaves except one at the top.

3. Plant a few of the cut stems around the edge of a pot filled with gritty compost. Water well and place outside to catch the rain.

4. You may need to check on them a few times but they should root on their own over the winter and be ready to be planted individually next summer.

Nedopekin Yuriy - Getty Images

Fruit and vegetables

• Garlic bulbs are perfect for autumn planting. Using a shovel, dig over the soil and apply a general-purpose fertiliser, then plant garlic bulbs 15cm apart with a trowel. 'Plant one clove per hole with the fat end pointing downwards and the tip 2.5cm below the surface of the soil. Protect the young plants by filling the holes and covering them with fleece. Water regularly when it's dry. Flower spikes should be removed,' advise the experts at British Garden Centres. Harvest bulbs once the leaves have turned yellow and flopped over.

• Sow spring cabbages now to provide you with delicious home-grown greens in the new year. Start transplanting your young cabbage plants into the soil, and remember, cabbage loves fertile, deep alkaline soil enriched with organic matter. Water plants well in dry weather and harvest as soon as they have formed good compact heads.

• When planted in autumn, purple sprouting broccoli will grow happily outdoors through winter for a delicious spring harvest. 'Mix in general-purpose compost, horticultural sand and stone or potting grit to ensure good drainage,' say the experts at British Garden Centres. It'll be ready to harvest in February for an early spring treat.

• Marrows and pumpkins should be picked but left in a sunny spot for a few days to harden up before being stored. If left out longer, they may start to rot before Halloween.

close up photo of floret of purple sprouting broccoli, brassica oleracea var italica the variety can be harvested in early spring
Martin Hambleton - Getty Images


Dig up any remaining potatoes so they don't get eaten by slugs. Leave the Christmas potatoes, which should still be forming. And swap, freeze, pickle or store any gluts of vegetables you may have.

The benefits of earlier growing come to fruition with the bulk of the harvest coming home in September. The experts at British Garden Centres share what you can pick from your vegetable garden now:

  • Maincrop potatoes

  • Tomatoes

  • Herbs

  • Sweetcorn

  • Courgettes

  • Cucumbers

  • Chillies

  • French and runner beans

  • Raspberry plants (pick the fruit and cut back the fruited canes to ground level)

  • Harvest apples, pears, and plums (plus, pick up any fallen fruit).

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Bedding plants

Heartsease, also known as Viola tricolor and wild pansy, is the loveliest viola with a mix of yellow, white and purple in its delicate flowers. Have a go at sprinkling some seeds into trays and place on a sunny windowsill. You should get a crop of beautiful flowers that you can use for winter pots and hanging baskets.


This is the time to sort out the lawn. Grass has an autumn growth spurt about now so any stress you put it under should grow out before winter sets in. Re-sow or lay new turf on areas that are bare or patchy. If you've got a lot of thatch in your lawn – old grass along the top of the soil –it might be a good idea to scarify the lawn. It's hard work but not technically difficult, just get a spring-tined rake and rake it out. It leaves the lawn in a bit of a mess in the short term but in time it will look healthier and greener.

Another treatment that creates a short-term mess but has long-term benefits is aerating or spiking the lawn. If it's prone to waterlogging or a lot of moss grows in it, it may be compacted. Spiking it with a garden fork will help to get water and air through the soil.

daisy in autumn meadow
Rosmarie Wirz - Getty Images

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