What to do in the garden in September
There's always something to be doing in the garden, whether it's pruning, tidying or sowing, so we've put together our top gardening tasks for September.
In the flower garden
- • Continue to feed and dead-head your hanging baskets and container plants - they will often keep going until the first frosts.
- • Try autumn-sowing hardy annuals for bigger plants next year.
- • Start to divide herbaceous perennials as the weather cools. Make sure you water in the new divisions well.
- • Fill gaps in borders with autumn flowering plants such as sedum and chrysanthemum to extend the colour to the end of the season.
- • Plant hyacinth and amaryllis bulbs for forcing, to ensure a crowd of colourful blooms at Christmas. Perfect for a home made Christmas present!
- • Plant spring-flowering bulbs such as daffodils, crocus and hyacinths now.
- • Plant out any biennial plants sown earlier in the year, or if you didn't have time you can buy plants now. This includes foxgloves, wallflowers and Violas.
- • September is a good time to plant new perennials as the soil is still warm but there is generally more rainfall.
- • With wetter weather arriving this month, it's the ideal time to order trees and shrubs. They will grow vigorously next spring if planted this autumn.
- • Keep deadheading annuals and perennials to extend their performance.
- • Keep dead-heading your Penstemons, Dahlias and Roses to prolong flowering.
- • Prune any late-summer flowering shrubs such as the rock rose (Helianthemum).
- • Prune climbing roses and rambling roses once they've finished flowering (unless they are repeat-flowering, in which case leave them).
- • Keep your Camellias and Rhododendrons well watered at this time of year to ensure that next year's buds develop well.
In the vegetable garden
- • Keep harvesting crops. If you have a glut of fruit and veg try freezing, drying, pickling, and storing so that you can benefit from them later on. Take a look at our recipes page for ideas on what to make with your produce!
- • It's important to pinch out your cordon tomato plants now if you haven't already done so. This will concentrate the plant's energy into producing ripe fruits.
- • To test if sweetcorn is ready, pinch a kernel - it will release a milky sap when ripe. If the kernels are starchy you've left it too late, if they're watery they need a little longer to ripen!
- • Pull or cut off the foliage of maincrop potatoes at ground level 3 weeks before lifting them to prevent blight spores infecting the tubers as you lift them. This will also help to firm the skins of the potatoes.
- • Spread newly dug potatoes out to dry for a few hours before storing them in in a cool dark place. Store them in paper or hessian sacks as this will allow the crop to breathe while it is in storage. Only store undamaged, disease free tubers - one rotten potato can ruin your whole crop!
- • Help your pumpkins ripen in time for Halloween by removing any leaves shadowing the fruits.
- • Place pumpkins and squashes on a piece of slate or wood to raise them off the wet soil and prevent rotting.
- • Keep feeding and watering French and runner beans to make the most of them. Continue harvesting little and often to prevent them setting seed.
- • Start the autumn cleanup. Remove any old crops that have finished and clear away weeds to leave your plot clean and tidy for the winter.
- • When beans and peas finish cropping simply cut the plant away at ground level, leaving the roots in the soil. These crops fix nitrogen which is slowly released into the soil as the roots break down.
- • Pot up some mint and parsley for the kitchen windowsill, to use through the winter.
- • Cover your brassicas with netting to prevent birds making a meal out of them.
- • The end of this month is the perfect time to start planting garlic bulbs for cropping next year.
- • Start planting autumn onion sets.
In the fruit garden
- • Order your strawberries, raspberries, blackberries or currant bushes for cropping next year as these plants are best planted during the dormant season.
- • Pot up strawberry runners to make extra plants for next year. Plant out any rooted runners of strawberries for a good crop next year
- • Tidy up your strawberry plants and clear away any used straw, as this will harbour pests and diseases over winter.
- • Look out for rotting fruits on your pear, apple and plum trees. Pick them off as they will spread disease if left on the tree.
- • Pick blackberries as they ripen and use straight away or freeze some for use later on.
- • To test when apples are ripe gently lift them in the palm of your hand or give them a gentle pull - they should come away easily.
- • Pick plums. If you have more than you need, then freeze them by washing, halving and stoning them, before laying them out on a tray in the freezer. Once frozen, pack them in freezer bags.
- • Mow long grass under fruit trees to make it easier to spot windfall fruits.
- • Cover wall-trained peach trees to prevent peach leaf curl from taking hold. The fungus needs wet conditions to infect the plants.
- • If you haven't already, cut back the fruited canes of your summer raspberries, leaving the new green canes for next year’s crop. Tie in next year's raspberry canes to support wires or fencing.
- • Take hardwood cuttings to increase your stock of currants, gooseberries & figs.
In the greenhouse
- • Empty pots, old compost and decaying plant material can harbour unwanted pests in your greenhouse and provide ideal shelter for them over winter. Clean out your greenhouse to reduce the risk of pests and diseases next year.
- • Don’t forget to remove the shading from your greenhouse towards the end of the month so that your plants receive the maximum amount of light.
- • Water early on in the day so the greenhouse is dry by the evening. Damp, cool nights can encourage botrytis.
- • Close vents and doors late in the afternoon to help trap in heat overnight. This will ensure your plants crop for as long as possible.
Looking after your lawn
- • Create a new lawn from turf or seed - autumn weather is favourable for good lawn establishment.
- • Raise the height of your mower blades as grass growth slows down.
- • Now is a good time to carry out essential lawn maintenance to avoid waterlogging and compaction. Try aerating your lawn with a garden fork, raking thatch from the surface and repairing dead patches.
- • Apply a special lawn top-dressing after carrying out maintenance work. Follow the instructions on the packet carefully.
- • You can feed your lawn with an autumn fertiliser now, which is rich in potassium and low in nitrogen.
- • Now is the perfect time to use a biological control (nematodes) if you suspect damage from lawn chafers or leatherjackets.
From your armchair
- • Make rough sketches of your flower borders and vegetable plot to help plan for next year. Reflect on what worked and what didn't!
- • Think about which bulbs you would like for next spring - now is the time to order ready for autumn planting.
Other jobs about the garden
- • If you have clay soil, now is the best time to improve it before it becomes too wet or frozen. Incorporate organic matter and/or horticultural grit.
- • Sow green manures such as mustard, clover and rye grass on uncultivated areas to improve soil and keep weeds down over winter.
- • Create compost bins in preparation for all the fallen leaves and dead plant material which you'll be collecting over the coming months. Autumn leaves make a great addition to compost bins and are ideal for making leaf mould.
- • Dispose of diseased plant material by burning it or putting it in with your household waste. Don’t compost it as the spores may remain in the compost and reinfect your plants.
- • Raise pots off the ground for the winter by using bricks or 'pot feet', to prevent waterlogging.
- • Clear pond weeds and net your pond in anticipation of autumn leaf fall.
- • Perennial weeds are more vulnerable to weedkillers in the autumn. Use a glyphosate-based weedkiller to kill both the leaves and roots.
- • Install water butts to collect rain this autumn and winter. Rain water is great for watering ericaceous plants such as blueberries, Rhododendrons and Camellias.