What to do in the garden in September


  • Continue harvesting crops. If you got too many fruits and veggies at once, pickle, dry and freeze them, so you can enjoy them till the next season.
  • Sow lettuces such as ‘Dandie’ and ‘Kwiek’ in frames, as last month, together with New Zealand spinach in the open ground.
  • Pot up some parsley and mint to enjoy them in your kitchen through the winter.
  • Pot up chives for taking indoors.
  • Cut off or pull the foliage of main crop potatoes at ground level, three weeks before you lift them up. This will prevent blight spores infecting the tubers as you lift them and help to firm the skins of the potatoes.
  • Leave newly dug potatoes to dry for a few hours before storing them. Store them in a dark and cool place, in hessian or paper sacks. This will allow the crops to breathe. Only store healthy, disease free tubers, as one little rotten potato can ruin the whole crop!
  • Continue earthing up celery up to the base of the leafy part of the plant. While wrapping a newspaper around the celery, and holding in place with a string can keep the soil out of the heart of the plant before earthing-up.
  • Keep feeding and watering and picking runner beans to encourage the remainder to develop. Use Ecoworm Soil Extract for feeding.
  • Pinch out the tips of outdoor tomatoes to facilitate ripening of the fruit.
  • Cloche peas, French beans and tomatoes that still have maturing fruit.
  • Fork outdoor peppers slightly out of the ground, so that they lay down without breaking the stem. Peppers that have not ripened by the end of the season can be left on the plants, while hanging the whole plant upside down in a cool and dry place, where the peppers can continue ripening.
  • Cover up your brassicas with nets, to protect them from birds.
  • Harvest sweetcorn. Pinch a kernel to test if they are ready. It will then release a milky sap of ripe. If the kernels are watery, let them ripen longer. If they are starchy, you have left them too long.
  • Continue blanching endive, celery and leeks.
  • Raise pumpkins and squashes off the ground to prevent rotting. Place them on a piece of wood or slate.
  • Remove any leaves shadowing pumpkins, so they can ripen for Halloween.
  • Cut pea and bean plants to ground level once they finished cropping. Leave the roots, as they will slowly break down and release nitrogen back into the soil.


  • Keep picking the remaining fruits as they become ready. Do it when the weather is dry, because wet fruits are always likely to attract diseases.
  • Cover up fruiting autumn raspberries and perpetual strawberries during the nights, as well as cold and wet days to keep them longer. Use polytene sheeting for raspberries, and clothes or tunnels for strawberries.
  • Tidy up strawberries and remove all the used straw, as it will attract pests and diseases over winter.
  • Pot up strawberry runners to make extra plants for next year.
  • Fix grease bands round fruit trees.
  • Prune all the remaining summer raspberries, blackberries, or hybrid cane fruit that finished fruiting.
  • Pick blackberries as they ripen and use right away, or freeze them for later use.
  • Pick plums, peaches, figs frequently and regularly, to avoid them being spoiled by cooling weather.
  • Pick of rotting fruits from pear, apple and plum trees, or they will spread disease if left on the tree.
  • Thin figs.
  • Cover wall-trained peach trees in order to prevent peach leaf curl from taking hold. Fungus needs wet conditions to infect the plant.
  • Harvest plums and if you end up having more than you need, freeze them. Wash them, halve and lay on a tray in the freezer. Once frozen, pack them into freezer bags.
  • Pick apples and pears for storing. Only completely healthy fruits should be picked for storing. Any damage or fungal mark should be put aside and used first. A good storage should be dark and have consistent low temperature. Try to avoid wooden sheds, as the temperature there changes frequently.
  • Finish pruning and training fan-trained peaches and nectarines. Meanwhile, plum pruning can be carried on since last month.
  • Prune trained apple and pear trees, which were pruned earlier in the summer, but which had immature shoots left unpruned.
  • Take hard cuttings of gooseberries, currants and figs to increase your stock.


  • Mow less frequently and raise the height of the blades as grass growth slows down.
  • Give your lawn an autumn feed with Ecoworm Soil Extract for Lawns. Do it after scarifying and aerating, but before applying the top dressing. (Rich in potassium and low in Nitrogen).
  • Repair patchy lawn and create new lawn with turf or seed. Autumn is the perfect time for establishing new lawn. Do it this month, and do not wait until October, or there might be a risk of disease attack of weak seedlings.
  • Deal with pests and problems.


  • Continue spraying roses against mildew and black spot.
  • Plant evergreens and conifers. September is the best month for it because the ground is still warm, but also quite moist, which encourages early root growth and quick establishment.
  • Prune rambling roses and weeping standards.
  • Plant trees, shrubs, or herbaceous plants that have been raising from the seed. September is the most suitable month for it.
  • Water when necessary.


  • Continue feeding and deadheading hanging basket and container plants. Use Ecoworm Soil Extract for Flowers to keep them going until the first frost.
  • Plant new perennials (towards the end of September), when the soil is still warm, but moisture levels are higher, and continue cutting back perennials that are dying and fading.
  • Continue collecting and storing seeds from perennials that are still forming seed heads and bring inside any tender perennials, such as fuchsias, gazanias, lantanas and abutilons, before frost hits.
  • Plant lilies outdoors and in pots.
  • Take cuttings of tender perennials (such as Pelargonium and Osteospermum), because they grow better from cuttings each year. Grow them in a greenhouse or on a light windowsill.
  • Keep on watering camellias and rhododendrons for the next years buds to develop well.
  • Do not leave gladioli, freesias and dahlias in the ground during the winter. If they are not killed by the cold weather, then slugs or mice will probably get to them.
  • Deadhead plants such as delphiniums, penstemons, dahlias, and roses to keep flowers coming.
  • Divide any overgrown alpines, and herbaceous perennials (such as crocosmias). This will give them strength and improve flowering for the coming year.

Read more:
What to do in the garden in August
What to do in the garden in October