Monthly Gardening Advice – September

Monthly Gardening Advice – September



  • Raise the mower blades before cutting fine lawns. This will help reduce stress.
  • Get your lawn ready for winter by applying an autumn feed. Scarify the lawn first then apply high potassium feed followed by a top-dressing.
  • During dry periods cut the lawn a little longer and invest in a mulching mower to help the lawn retain moisture.
  • Last chance to put down a lawn weed killer.
  • Loam & soil top dressing can be applied at the rate of 2kg per sq m, working it well in with a stiff broom or the back of a garden rake. If you use a proprietary product follow the specific instructions on the pack.

Houseplant Care

  • Start reducing watering of houseplants as light levels drop.
  • Ventilate and shade sunrooms and conservatories to prevent scorch damage to leaves.
  • When you start to bring plants back indoors check them for pest and disease. Treat if necessary.
  • Plant up hippeastrum (amaryllis) bulbs and prepared hyacinths for Christmas displays.
  • September is an ideal time to apply biological control for pests like vine weevil by using nematodes.

Jobs To Do In The Garden

  • Water tubs and new plants if dry and liquid feed.
  • Deadhead faded flowers to encourage more and prolong the flowering period.
  • Make a start dividing herbaceous.
  • Plant spring flowering bulbs such as daffodil, tulip, crocus and hyacinth.
  • Make sure early flowering shrubs like camellia and rhododendron are well watered during dry periods to ensure good flower bud development.
  • Don’t neglect hanging baskets – feeding, watering and deadheading will keep them going till mid-autumn.
  • Take cuttings of pelargoniums and osteospermum as soon as possible.
  • Start collecting seed from your favourite plants.
  • Cut back taller perennials like asters to stop them breaking in the wind.
  • Start to bring in plants like fuchsia and abutilon before frost damage them.
  • Allow the first frost to blacken foliage on dahlias and cannas before lifting the tuber.
  • Check for first signs of vine weevil damage.

Jobs To Do In The Greenhouse

  • Remember to ventilate the greenhouse on sunny days and on the warmest days you may need to damp the flooring down to increase the humidity.
  • Give plants more space as they grow to help avoid pest infestations.
  • Check for vine weevil larvae in containers.
  • Regularly inspect plants for pest and disease.
  • Start cleaning greenhouse ready for use in the autumn.

The Vegetable Garden

  • Prune apricot, nectarines, peaches, plums, gages and damson immediately after harvest.
  • Now is the time to sow vegetables for overwintering to mature next spring like turnip, winter lettuce, onion sets and spinach.
  • Continue consistent supply of water to help avoid diseases, disorders and bolting.
  • Water tomatoes & peppers regularly to avoid blossom end rot.
  • Cut back old fruiting canes on blackberries and hybrid berries after fruiting.
  • Don’t delay summer pruning restricted fruits (fans and espaliers).
  • Dig remaining potatoes before slug damage spoils them.
  • Lift and pot up rooted strawberry runners.
  • Continue to harvest onions, garlic, sweet corn, figs, beans, carrots, potatoes, salads, raspberries, blackberries, courgette, cucumbers, tomatoes cherries, strawberries, early grapes, blueberries, gooseberries, melon, apples, pears, sweetcorn, peppers and kiwifruit.
  • Hoe off weeds in dry weather.
  • Continue to cut out old fruited canes on raspberries.
  • Celery can be earthed-up for the final time this month, leave just a tuft of foliage.
  • Net leafy vegetable crops with bird proof netting.

Wildlife & Bird Care

  • Hip bearing roses can be left un-pruned to produce fruit.
  • Clean out birdbaths.
  • Keep birdbaths topped up.
  • Refill bird feeders.
  • Start building a hedgehog hibernation box.
  • Trim hedges less frequently to encourage wildlife to shelter and feed.
  • Make sure your pond is more wildlife friendly (by planting round the pond and creating a shallow edge so wildlife can access the pond safely).
  • Give meadows a final cut before winter aim for 7.5cm (3 inch height and once cut leave clippings to lie for a couple of days to allow wildlife to crawl away and the rake up clippings.
  • Allow seed heads to develop on some plants for a source of food.
  • Plant perennials to attract insects

Any Other Advice

  • Collect grey water for watering containers and baskets.
  • Hang yellow card sticky traps in greenhouses and conservatories.
  • Clean out cold frames, so they are ready for autumn.
  • Net ponds before leaf fall gets underway.

Enjoy your garden and don’t forget to take time and stop and stare at the wonder of nature. Happy gardening!