September is pleasantly warm enough to enjoy pottering in the garden, with the relentless heat of previous months usually behind us. The evenings arrive earlier and are slightly cooler, a sign of the changing conditions of autumn. There’s plenty to keep you active in all areas of the garden, with fruit to be harvested, bulbs to plant ready for the spring, seeds to save from spent flowers, and perennials to plant out in the borders.


What vegetables to plant in September

Sowing vegetables in September will bring spring harvests and help to cover the ‘hungry gap’ between seasons:

  • Lettuce
  • Spinach
  • Chard
  • Kale
  • Spring onions
  • Spring cabbage

They can all be sown as seeds, straight into prepared soil. Protect from birds with tightly secured netting.

What vegetables to harvest in September

What vegetables to harvest in September

September is the pinnacle of the vegetable growing season, with heavy quantities of veg available to the home grower:

  • Aubergine
  • Beetroot
  • Broad beans
  • Broccoli
  • Butternut squash
  • Cabbage
  • Cauliflower
  • Carrots
  • Celeriac
  • Celery
  • Courgettes
  • Cucumber
  • French Beans
  • Kale
  • Leeks
  • Lettuce
  • Peas
  • Peppers (chilli)
  • Peppers (sweet)
  • Potatoes
  • Pumpkins
  • Radish
  • Runner beans
  • Summer cabbage
  • Sweetcorn
  • Tomatoes
  • Turnips

Vegetable plant maintenance in September

There is plenty to do in the vegetable patch to keep it productive throughout September:

  • Broccoli, Cabbage & Cauliflower - keep netted with a fine mesh to stop cabbage white butterflies from landing and laying eggs. These turn into caterpillars which can then destroy crops.
  • Brussels sprouts - earth up and firm down soil around plants, to prevent rocking in windy weather.
  • Celeriac - remove horizontal leaves to expose the crown and help the root bulk up.
  • Chilli peppers - keep harvesting to extend the productive season as long as possible. They can be used fresh, frozen or dried out for use over the winter.
  • Cucumber - pinch out the growing tip, water and feed with tomato fertiliser.
  • French & Runner beans - allow a couple of pods to dry out on each plant. Collect these and place in a paper bag until the spring when they can be sown again.
  • Leeks - earth up the stems with soil to increase the length of the white stems.
  • Peas - add supports to peas sown in the summer. Twigs from early autumn pruning activities are perfect for this.
  • Radish - water well and pick every few days. They are quick growers, and the roots will quickly go woody and become unpalatable if left too long.
  • Tomatoes - pinch out the tops of plants. Remove any growth below the lowest fruits, any leafy growth which is shading fruit, and any new flowers. This will increase air flow and help the plant to ripen the remaining fruit.
  • Turnips - thin these to 8cm (3in) apart. The leafy tops of the ones which you remove can be used in the kitchen as greens - in stews and omelettes, for example.

If the hot and dry weather of the summer has continued, make sure to keep plants well-watered. This is particularly important for new seedlings, which can quickly wither without a little help.

Things to do this month
  • Trim evergreen hedges, such as Yew, whilst they are still growing.
  • Add fallen tree leaves to the compost heap or a dedicated leaf mould pile.
  • Turn the compost heap and keep adding a mixture of different materials to it. Use a compost accelerator to encourage activity in the heap and speed up the creation of compost.
  • Remove unwanted plants from the pond and add to the compost heap.
  • Cover ponds with netting to collect leaves and other debris which may blow in during the windier months of Autumn.
  • Take down netting in the greenhouse, or wash off shade paint, to make the most of shortening daylight hours.
  • Check that water butts and downpipes are in full working order ahead of wetter weather.
  • Raise pots from the ground so that excess water drains from them, rather than accumulating, freezing and then cracking in very cold weather.