September jobs and tips for your garden
September is generally a cooler, gustier month than August and the days are noticeably shorter. While there's not as much to do in the ornamental garden at this time of the year, if you have a fruit or vegetable patch, you'll be busy reaping the rewards of harvest. It's also time to get out and start planting spring-flowering bulbs for next year and you can collect seeds for next summer's colour too. Make the most of the remaining warmth while you can!
• Start to reduce the frequency of houseplant watering.
• Clean out cold frames and greenhouses so that they are ready for use in the autumn.
• 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
• 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.
• Perennial weeds are more vulnerable to weed killers in the autumn. Use a glyphosate-based weed killer 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.
• Pick autumn raspberries.
• For raising new blackberry plants, bury tips into the soil of any shoots that have developed this year, as they
will quickly form roots and new shoots will develop next spring. Once this has happened the new plants can
be separated and planted where you plan to grow them.
• Try to avoid wasp damage to early fruiting apples by hanging wasp traps in the branches of the trees.
• All shoots that have carried peaches should be pruned so that newly formed ones can be tied to ones
formed this year and these will flower next spring.
• Crops of raspberries, blackberries and other autumn-fruiting varieties should be covered with netting to
keep birds away. However, the netting should be checked daily making sure no birds or any other animals
• Order your strawberries, raspberries, blackberries or currant bushes for cropping next year as these plants
are best planted during their 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
• 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. Pick fruit from these
early ripening varieties as soon as they are sweet enough to eat as they don’t keep.
• 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 into 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.
• Keep up with watering of new plants, using rain or grey water if possible.
• Plant spring flowering bulbs.
• Collect and sow seed from perennials and hardy annuals.
• Continue to feed and dead-head your hanging basket 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
• 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. Also 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
• Once the summer bedding plants have been removed, plant spring flowering plants such as bellis (daisy),
pansy, polyanthus, primrose and wallflowers along with spring flowering bulbs.
• It is a little early to plant tulip bulbs which should be left until November to avoid attacks of Tulip Fire. This
disease causes scorched areas on the leaves and spotting on the flowers.
• The following hardy annuals can be sown outdoors – calendula, cheiranthus, godetia, larkspur, nigella and
• Wild flowers that can be sown direct outdoors are field scabious, field cornflower and feverfew. Using a cold
frame the wild flowers primrose and cowslip can also be sown.
• In the greenhouse sow cyclamen, pelargonium, schizanthus and strelitzia.
• Sweet peas can be sown in a cold frame or unheated greenhouse to over-winter, the young plants can then
be planted out in March/April to obtain early blooms.
• It is now a good time to begin watering dormant cyclamen pot plants which were left to die down for a rest.
• When rose blooms have faded a last deadheading of roses can be done, and taller stems may be slightly
shortened so that movement from wind can be reduced.
• During the early part of this month stem cuttings may be taken. Cut a length of stem, remove the soft tip just
above a leaf joint, cutting below a joint at the base removing all but the top three leaves. Place directly into
the soil approximately 30cm (12″) to about half its length somewhere in the garden where they can remain to
root and develop for about a year.
• Gladioli are still giving enjoyable displays in the garden but it might be nice to cut a few spikes for indoors.
• Should thrips be causing a nuisance spray with Bug Clear. Once flowering has finished, the corms may be
lifted, cleaned and carefully stored for planting out again next spring.
• So that dahlia stems do not break in the wind tie them to supports such as canes.
• Remove any deadheads and cut some flowers for a nice display indoors.
• When lily bulbs become available they can be planted as soon as you want.
Bedding and Hanging Baskets:
• To make sure displays last well into autumn remember to still give them a little attention.
• Water regularly, daily if possible, keep pests under control and, of course, remove any fading blooms.
• Pot any of the tender plants you may wish to save for next year so that they are allowed to become
established in readiness for being placed under cover when the weather starts getting cooler.
• Early September is an ideal time to sow a new lawn or make repairs to an existing lawn.
• Grass growth is slowing, therefore, reduce the frequency of mowing also raise the height of your mower
• Create a new lawn from turf or seed - autumn weather is favourable for good lawn establishment.
• Now is a good time to carry out essential lawn maintenance to avoid waterlogging and compaction. Try
aerating your lawn with a garden fork, removing thatch or dead leaves from the surface with a rake and
repairing dead patches. Use a specialist lawn scarifier if you have a large area to cover.
• Apply a special lawn top-dressing after carrying out maintenance work. Follow the instructions on the packet
• 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
• Dig up remaining potatoes before slug damage spoils them.
• Cover leafy vegetable crops with bird-proof netting.
• Plant onion sets of an over-wintering variety from the middle of the month.
• Sow winter lettuce Valdor and Winter Density.
• A few cut-and-come again salad varieties could be planted in pots for tasty leaves in the autumn.
• Lift maincrop potatoes and allow to dry prior to storing in wooden trays in a dark, cool, frost-free shed or
• Transplant spring cabbage into their final positions.
• For a supply of herbs during the winter, pot up plants of basil, marjoram, mint, oregano and parsley and
grow them on the kitchen windowsill.
• Crops should be picked regularly ensuring they are always fresh and tender, and items such as courgettes
and beans shouldn’t be left too long prior to picking.
• Tomatoes and chillies in greenhouses should still be watered during late summer.
• Celery plants reaching required size can be lifted carefully with a hand fork.
• 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.
• 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.
• Pinch a kernel to see if it's ripe.
• 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 main crop 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 clean up. 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.