September is the best month for all of this in the UK: the soil is still warm so grass seed germinates fast, and autumn rain keeps everything moist while the new grass roots.
September is the best month of the year to renovate a tired UK lawn. After a summer of footfall, drought and mowing, most lawns end the season compacted, full of thatch and patchy. Autumn fixes all of that: the soil is still warm enough for grass seed to germinate quickly, and the reliable autumn rain keeps new grass growing without you dragging a hose around.
This guide takes you through the full autumn lawn renovation in the order the jobs should be done — scarify, aerate, top dress, overseed and feed — with the timing and the one feeding rule that makes the biggest difference. It pairs with our wider guide to what to plant in September, which covers the rest of the month’s jobs.
Why autumn is the best time for lawn care
Grass roots most strongly in warm soil and cool air, which is exactly what autumn provides. Work done now repairs the summer’s damage and sends the lawn into winter strong, so it greens up early next spring. The RHS recommends autumn — starting in September — for the heavy renovation jobs of scarifying and aerating, precisely because the lawn has time to recover before growth slows.
Spring is the other window for lawn care, but autumn has two advantages: weed competition is lower, and the combination of warm soil and damp weather gives newly sown seed the best possible start. Do the work now and you avoid trying to establish grass in the heat and drought of next summer.
The autumn lawn care routine, in order
Order matters. There is no point sowing seed onto a thatchy, compacted surface, and no point top dressing before you have aerated. Work through the five steps in sequence, ideally over a weekend or two while the weather is mild and the soil is moist but not sodden:
Scarify to pull out the dead thatch and moss choking the base of the grass.
Aerate to open up compacted soil and let air, water and roots move freely.
Top dress to fill the holes and improve the surface.
Overseed the bare and thin areas exposed by scarifying.
Feed with an autumn formulation to harden the grass for winter.
Step 1: Scarify to remove thatch and moss
Rake out the thatch and moss first — this is scarifying, and it comes before everything else. Thatch is the layer of dead grass, old clippings and moss that builds up at the base of the lawn; a thin layer is normal, but when it gets thick it stops water and nutrients reaching the soil and creates a damp home for moss and disease. Vigorous raking pulls it out.
For a small lawn, a spring-tine rake and some effort will do the job; drag it firmly across the lawn in different directions to comb out the debris. For anything larger, a powered scarifier or a scarifying cassette on a lawn rake saves a great deal of work. Expect to pull out a surprising amount of material — bag it up for the compost heap (moss is best left out of home compost unless your heap gets genuinely hot).
If your lawn is mostly moss, treat the underlying cause as well as raking it out. Moss thrives where there is shade, poor drainage and compaction, so the aerating and top dressing that follow are part of the long-term fix.
Step 2: Aerate to relieve compaction
Spike the lawn all over to relieve compaction. Summer footfall squeezes out the air spaces that roots and water need, and aerating opens the soil back up.
Fork vs hollow-tine
For most lawns, pushing a garden fork 10-15 cm into the turf every 15 cm or so, then easing it back to crack the soil, is enough. On heavy clay or a lawn that lies wet, a hollow-tine aerator does a better job: it pulls out small cores of soil, leaving wider holes that genuinely relieve compaction rather than just slitting the surface. The RHS specifically recommends hollow-tine aeration for clay and waterlogged lawns. Leave the cores to dry, then rake or break them up.
Step 3: Top dress
After aerating, brush a thin layer of free-draining material — usually a sand-and-loam mix — across the lawn. This top dressing fills the aeration holes, gradually improves the soil structure at the surface, and levels out minor bumps and hollows.
Spread a thin layer over the lawn (roughly 1-2 kg per square metre, in a couple of small heaps) and work it in with the back of a rake or a stiff brush until it disappears between the grass blades and into the holes. Never bury the grass — you should still see the leaves once you have brushed it in. On sandy soils that already drain well, top dressing is optional; on clay it is one of the most useful things you can do over several autumns.
Step 4: Overseed bare and thin patches
Sow fresh grass seed into every thin and bare patch the scarifying and aerating have exposed — September’s warm soil is ideal for filling them. Overseeding thickens the sward, crowds out moss and weeds, and is the single biggest improvement most lawns can make.
Choose a grass seed mix that matches how you use the lawn. For a family lawn, pick a hard-wearing mix — roughly 70% dwarf perennial ryegrass (look for proven cultivars such as ‘Eurodiamond’) and 30% strong creeping red fescue (such as ‘Eurocarina’) — which shrugs off children and pets. For a finer, more formal finish, choose an ornamental fescue-and-bent mix, which looks neater but needs closer mowing and more care. Established UK ranges such as Johnsons Lawn Seed and Gro-Sure cover both; the RHS advises matching the mix to how hard the lawn is used rather than chasing the finest-looking grass.
Loosen the surface of bare patches with a rake so the seed makes contact with soil.
Scatter the seed by hand or with a spreader at the rate on the pack — roughly 25-35 g per square metre for overseeding, more on bare soil.
Lightly rake or brush the seed in, and keep the area moist until it germinates, which in September’s warmth usually takes 7-14 days.
Keep off the new grass and delay the first mow until it reaches about 5 cm, then only take the top off.
Step 5: Apply an autumn lawn feed
Finish by applying an autumn lawn feed — one that is high in potassium and phosphorus and low in nitrogen. This is the step people most often get wrong, because an autumn feed is formulated very differently from a summer one. Potassium hardens the grass and toughens it against cold and disease, while phosphorus encourages root growth.
Do not use leftover summer feed in autumn. Summer feeds are high in nitrogen, which pushes soft, sappy leaf growth — exactly the wrong thing going into winter, as that lush growth is prone to disease and frost damage. Buy a product labelled specifically as an autumn or autumn/winter lawn feed, apply it at the stated rate when the soil is moist, and water it in if no rain is forecast. Garden centres, B&Q and the main online retailers all stock autumn formulations from late summer.
Regional timing across the UK
September is the headline month, but exactly when to start depends on where you garden. In Scotland and the north of England, where the season turns earlier, begin scarifying and aerating in the first half of September so the lawn has time to recover before growth slows. In the milder south, you have the whole of September and often well into October to get the work done.
Wherever you are, the soil should be moist but not waterlogged, and the grass still actively growing. Avoid working on a sodden lawn — you will compact it further and tear the turf. If September is unusually dry, wait for rain to soften the ground before aerating.
Ongoing autumn maintenance through to winter
The renovation above is the big once-a-year job, but a tired lawn also rewards a few light, regular tasks right through autumn until growth finally stops.
Raise the mowing height and mow less often. Grass keeps growing while the soil stays above about 5°C, so don’t put the mower away yet — just lift the blades around 5 mm above your summer setting and cut only when the lawn needs it. A slightly longer sward makes the most of short autumn days and copes better with cold. Never mow when the grass is wet or frosted, as that bruises the blades and compacts soft ground.
Clear fallen leaves promptly. A layer of wet leaves blocks light and air within days and encourages disease and moss. Rake or mow them off once or twice a week through leaf-fall; shredded leaves rot down into excellent leafmould for your borders.
Keep moss in check. Damp, shaded autumn conditions are when moss spreads fastest. Light raking and the aeration described above do more lasting good than repeated moss-killer — treat only badly affected patches, then rake out the dead moss.
Stay off frosted or waterlogged turf. Walking on frozen or saturated grass leaves lasting bald footprints and undoes your aeration work. Once hard frosts arrive, keep foot traffic to paths.
Common mistakes to avoid
Using summer feed in autumn
Why it happens: There’s half a bag left over from spring. How to fix it: Save it for next spring and buy a proper autumn feed — the high nitrogen in summer feed does real harm going into winter.
Scarifying a wet or soft lawn
Why it happens: People work whenever they have a free weekend. How to fix it: Wait until the surface is dry enough to walk on without sinking; scarifying wet turf tears it and makes a mess.
Mowing the new grass too soon or too short
Why it happens: The lawn looks ready. How to fix it: Let overseeded areas reach about 5 cm, then only take the top off with the mower on a high setting for the first few cuts.
Skipping straight to seed without scarifying
Why it happens: Scarifying is hard work. How to fix it: Seed sown onto thatch rarely reaches the soil and mostly fails — do the raking first.
Tools and products you’ll need
You do not need much to renovate a lawn, and most of it you may already own. For the raking and spiking, a sturdy spring-tine rake and a garden fork cover a small lawn; for anything larger, a powered scarifier and a hollow-tine aerator are worth hiring or buying. Our guide to the best gardening tools for beginners covers the basics worth investing in.
Safety: powered scarifiers and hollow-tine aerators have sharp blades and tines. Wear sturdy gloves and stout footwear, keep hands and feet clear of moving parts, and keep children and pets off the lawn while you work.
For the finishing steps you will want a UK lawn seed mix suited to your lawn, a bag of sand-and-loam top dressing, and an autumn lawn feed. A simple drop or broadcast spreader makes seed and feed go down evenly, which matters more than it sounds — uneven feeding leaves stripes. Crocus, B&Q and the main online retailers stock seed, feed, top dressing and spreaders through autumn; buy the autumn feed specifically rather than reaching for a summer product.
Frequently Asked Questions
When should I scarify my lawn in the UK?
Early autumn is the main window — September is ideal in most of the UK, slightly earlier in Scotland and the north. The lawn should be moist but firm underfoot, and the grass still growing so it can recover. Spring is a secondary option, but autumn gives the best results because weed competition is low and the soil is warm.
What is the difference between scarifying and aerating?
Scarifying rakes out the thatch and moss sitting at the base of the grass, improving airflow and letting water in. Aerating spikes the soil to relieve compaction below the surface, so air, water and roots can move freely. You scarify first, then aerate — they tackle different problems and work best together.
What lawn feed should I use in autumn?
Use a feed labelled for autumn or autumn/winter, which is high in potassium and phosphorus and low in nitrogen. This hardens the grass and encourages roots for winter. Avoid high-nitrogen summer feeds in autumn — they force soft growth that is vulnerable to frost and disease.
Can I overseed and feed on the same day?
Yes. Scarify and aerate first, then overseed the bare patches, top dress, and apply an autumn feed — all in the same session is fine. Just keep the area moist afterwards so the seed germinates, and avoid heavy use until the new grass has established.
How long does grass seed take to germinate in September?
In September’s warm soil, most UK lawn seed mixes germinate in about 7-14 days, faster than a spring sowing into cold ground. Keep the seeded area consistently moist during that time, and delay the first mow until the new grass is around 5 cm tall.
What next
Lawn sorted — now the rest of the autumn garden. Lawn renovation is one of several September jobs. These guides cover what else to do this month:
Quick Answer: Which spring bulbs to plant in September
September is the month to plant daffodils, crocus, hyacinths, alliums and most other spring-flowering bulbs. Get them in while the soil is still warm so roots establish before winter. The one bulb to hold back is the tulip — those wait until November. Plant most bulbs at roughly two to three times their own height deep, in free-draining soil or peat-free compost, pointed end up.
Plant your spring bulbs in September and you set up the whole of next spring in an afternoon. Daffodils, crocus, hyacinths and alliums all go in from this month, and the earlier you plant them the better they establish. The soil is still warm from summer, autumn rain does the watering for you, and the bulbs put down roots before the cold arrives.
This guide covers exactly which bulbs to plant in September, how deep and how far apart to set them, and how to plant them in borders, pots and lawns. It also explains the one important exception — tulips — and the handful of mistakes that catch people out. It sits alongside our wider guide to what to plant in September, which covers the vegetables, fruit and maintenance jobs for the month.
Why September is the month for spring bulbs
Spring-flowering bulbs need a long, cool establishment period before they flower. Plant them in early autumn and the roots grow steadily through September and October while the soil holds its summer warmth, typically 12-15 °C at planting depth. By the time hard frosts arrive, the bulb is anchored and ready to sit out winter.
The RHS advises planting most spring bulbs — daffodils, crocus and hyacinths — by the end of September, and daffodils ideally in early autumn. Leave it until the soil is cold and wet and the bulbs root more slowly, flower less reliably, and are more likely to rot. There is no advantage to waiting, so once the bulbs arrive, get them in.
The exception, covered in full below, is the tulip. Tulips are planted later, from November, to reduce the risk of a fungal disease called tulip fire.
The best spring bulbs to plant now
Daffodils (Narcissus)
Daffodils are the most forgiving spring bulb and the best starting point for beginners. Plant them as early as you can in autumn — September is ideal — in a sunny or lightly shaded spot in fertile, well-drained soil. They naturalise happily in grass and under deciduous trees, coming back and multiplying year after year.
For pots and the front of borders, the compact Narcissus ‘Tête-à-tête’ is one of the most reliable and widely sold choices in the UK, flowering early with several small yellow blooms per stem. For naturalising in grass, ‘February Gold’ is a tough, early dwarf daffodil that spreads well. Both are popular, reliable garden performers.
Crocus
Crocus give you the first real splash of colour in late winter, often pushing through in February. Species crocus such as Crocus tommasinianus ‘Ruby Giant’ are superb for naturalising in lawns and gravel, where they seed around gently over time. The larger Dutch hybrids (‘Flower Record’, ‘Jeanne d’Arc’) give bigger, showier goblets for borders and pots.
Plant species crocus 7-10 cm deep and the larger Dutch hybrids a little deeper, around 10-12 cm. They are cheap, plant in minutes, and bees emerging on mild late-winter days rely on their early pollen.
Hyacinths
Hyacinths are grown for their scent as much as their colour, so plant them where you will brush past them — beside a path, in a pot by the door, or in a window box. ‘Delft Blue’ and ‘City of Haarlem’ (soft yellow) are long-established, reliable varieties. Plant 10-12 cm deep. Always wear gloves when handling hyacinth bulbs, as the bulb sap can irritate skin.
Alliums
Ornamental alliums produce dramatic spherical flower heads on tall stems in late spring and early summer, bridging the gap between the spring bulbs and the summer borders. Allium ‘Purple Sensation’ is the classic deep-violet variety, while Allium hollandicum and the larger-headed Allium cristophii are also widely grown. Plant in early autumn in free-draining soil and full sun, in a spot sheltered from strong wind so the tall stems do not get blown over.
Others worth planting in September
Muscari (grape hyacinth): Low, intense-blue spikes that naturalise readily. Excellent edging and good in pots. Plant 7-8 cm deep.
Snowdrops (Galanthus): Best planted “in the green” (as growing plants in late winter) rather than as dry bulbs, but dry bulbs planted early in autumn and kept moist can still establish.
Iris reticulata: Tiny, jewel-like dwarf irises for pots and the front of borders, flowering with the crocus. Plant 10 cm deep.
Planting depth and spacing (quick reference)
The single most common reason bulbs fail is planting them too shallow. As a rule of thumb, plant a bulb at two to three times its own height deep, and roughly two to three bulb-widths apart. Use the table below for the popular spring bulbs.
Bulb
Planting depth
Spacing
Best for
Daffodil (Narcissus)
3× bulb height (≈10-15 cm)
10-15 cm apart
Borders, grass, under trees
Crocus (species)
7-10 cm
5-8 cm apart
Lawns, gravel, pots
Crocus (Dutch hybrid)
10-12 cm
8-10 cm apart
Borders, pots
Hyacinth
10-12 cm
8-10 cm apart
Pots, window boxes, border fronts
Allium (large)
4× bulb diameter (≈15-20 cm)
20 cm apart
Borders
Muscari
7-8 cm
5 cm apart
Edging, pots
If you are ever unsure, deeper is safer than shallower. Bulbs set too near the surface are vulnerable to frost, drought and being turned up by squirrels.
How to plant bulbs in borders
Bulbs look most natural planted in generous, informal drifts rather than tidy rows. For the best effect, plant at least 10-15 bulbs of a single variety together.
Choose the spot: Most spring bulbs want sun or light shade and soil that drains freely. If your soil is heavy clay, add a handful of horticultural grit to each planting hole.
Dig to the right depth: Use a trowel or a bulb planter for individual holes, or lift a whole area of soil for a drift. Check the depth against the table above.
Set the bulb pointed end up: The pointed tip is the shoot; the flatter, often rooty base goes down. If you genuinely cannot tell, plant the bulb on its side — it will right itself.
Backfill and firm gently: Cover with soil, firm lightly to remove air pockets, and water in if the ground is dry.
Label or mark: Mark the area so you do not accidentally dig through the bulbs while they are dormant.
How to plant bulbs in pots and containers
Bulbs are made for containers. A single pot by the door delivers a hit of scent and colour exactly where you will see it, and you can grow several layers in one pot for a long, overlapping display. Containers are also the simplest way to start if you garden on a patio or balcony — our guide to the best containers and pots for beginners covers choosing the right size and material.
For pots, use a peat-free, multipurpose compost with some added grit for drainage; our guide to the best compost for container gardening explains the options. Make sure the container has drainage holes — waterlogged compost is the quickest way to rot bulbs over winter.
The “bulb lasagne” method. Plant bulbs in layers, largest and latest-flowering at the bottom, smallest and earliest at the top:
Add a layer of compost to a deep pot, then set the largest bulbs (daffodils, large alliums) near the base, around 15-20 cm down.
Cover with compost, then add a middle layer of hyacinths or Dutch crocus.
Cover again and finish with a top layer of the smallest bulbs (muscari, species crocus, Iris reticulata).
Top off with compost, water once, and stand the pot in a sheltered spot. The shoots thread past each other and flower in succession from late winter into spring.
Naturalising bulbs in grass
Daffodils and crocus are perfect for naturalising — planting in grass so they come back and spread each year for a meadow effect. The RHS recommends scattering bulbs by hand and planting them where they fall, which avoids a regimented look.
Throw a handful of bulbs gently across the area and plant each where it lands.
For daffodils, use a bulb planter to take out a plug of turf, drop the bulb in pointed end up, and replace the plug. For small crocus, lift a flap of turf with a spade, push the bulbs in, and fold the turf back.
The golden rule: do not mow the area until the bulb foliage has died down naturally, about six weeks after flowering. The leaves feed next year’s flowers, so cutting them early weakens the display.
What to wait on: tulips until November
Tulips are the one spring bulb you should not plant in September. Plant them too early, into warm autumn soil, and you increase the risk of tulip fire (Botrytis tulipae), a fungal disease that scorches leaves and flowers and can ruin a whole planting.
Wait until November, when soil temperatures have dropped below about 10 °C. Tulips cope perfectly well with late planting — even December is fine — so there is no rush. Store the dry bulbs somewhere cool and dry in the meantime, and plant them once the rest of the garden has been put to bed. If you want the detail on timing, our September planting guide and the October guide that follows it set the bulbs in their wider seasonal context.
Common mistakes to avoid
Planting too shallow
Why it happens: People underestimate how deep bulbs go. How to fix it: Use the depth table above and err on the deeper side — most spring bulbs want two to three times their height of soil over the top.
Planting tulips with everything else in September
Why it happens: It feels efficient to do all the bulbs at once. How to fix it: Keep tulips aside and plant them in November to dodge tulip fire.
Letting bulbs sit in waterlogged soil
Why it happens: Heavy clay or pots without drainage holes hold water. How to fix it: Add grit to planting holes and compost, and only ever use containers with drainage.
Cutting the leaves down too soon
Why it happens: The dying foliage looks untidy. How to fix it: Leave it for at least six weeks after flowering so the bulb can build up reserves for next year.
Where to buy spring bulbs in the UK
Buy bulbs as soon as they appear in late summer, while the choice is widest and the bulbs are freshest. For our pick of the best varieties to buy and where to find the best value, see the buyer’s guide to spring-flowering bulbs. Look for firm, plump bulbs with no soft patches, mould or signs of sprouting. Bigger bulbs of a given variety generally give bigger, more reliable flowers.
Specialist mail-order suppliers such as Suttons, Thompson & Morgan and You Garden carry the widest range of varieties and despatch at the right planting time, while Crocus stocks bulbs alongside the peat-free compost and bulb planters you will need. For a few packets to get started, the bulb stands in garden centres, B&Q and supermarkets in September are perfectly good — just buy early before they dry out on the shelf. A simple long-handled bulb planter makes light work of naturalising in grass and is worth having if you are planting more than a handful.
Frequently Asked Questions
When is it too late to plant spring bulbs?
Daffodils, crocus and hyacinths are best in by the end of September, but you can keep planting into October and even November if you run late — they will simply flower a little later or less strongly. Tulips are the exception and are deliberately planted from November. As long as the ground is not frozen or waterlogged, get bulbs in rather than storing them.
How deep should I plant daffodil bulbs?
Plant daffodils at about three times the height of the bulb, which usually works out at 10-15 cm deep. In light, sandy soil go towards the deeper end; in heavy clay, slightly shallower with grit underneath for drainage. Too shallow is the main reason daffodils come up “blind” with leaves but no flowers.
Can I plant bulbs in pots in September?
Yes — September is ideal for planting bulbs in pots. Use a peat-free multipurpose compost with added grit, make sure the pot has drainage holes, and try the “bulb lasagne” method of layering different bulbs for a long display. Stand the pots in a sheltered spot and water sparingly over winter.
Why can’t I plant tulips in September?
Planting tulips in warm September soil increases the risk of tulip fire, a fungal disease that thrives in warmth. Waiting until November, when the soil has cooled below about 10 °C, greatly reduces that risk. Tulips tolerate late planting, so there is no benefit to planting them early.
Do I need to feed spring bulbs?
Bulbs contain most of the food they need to flower the first spring, so feeding at planting is optional. To build up strong flowering for following years, apply a balanced or high-potassium feed as the leaves appear in spring and let the foliage die back naturally. Bulbs naturalised in grass rarely need feeding at all.
What next
Plant the bulbs, then plan the rest of the month. Spring bulbs are one job on a busy September list. These guides cover what else to plant, sow and tidy now:
Quick Answer: Top 5 Things to Plant in September UK
Overwintering onion sets — plant ‘Radar’ and ‘Senshyu Yellow’ now for a June harvest
Spring bulbs — daffodils, crocuses, hyacinths, and alliums go in from this month
Green manures — sow field beans, crimson clover, or phacelia on bare soil
Winter salad leaves — final outdoor sowings of ‘Winter Density’ AGM lettuce, spinach, and radish
Strawberry runners — plant ‘Cambridge Favourite’ AGM and ‘Florence’ AGM for next summer’s crop
September marks the shift from summer harvesting to autumn planting. The soil is still warm from summer, germination is reliable, and there is a full programme of overwintering crops, bulbs, and green manures to get into the ground before temperatures drop.
September is the gardener’s pivot point. While the borders are still heavy with tomatoes, beans, and courgettes, the real work this month is forward-looking: getting overwintering crops established, sowing green manures on cleared beds, and planting the bulbs that will light up your garden next spring.
The soil is warm — typically 12-15 °C at root depth — which means seeds germinate quickly and transplants establish without fuss. Yet the shortening days and cooler nights signal that the window for outdoor sowing is closing fast. What you plant in September determines how productive your garden will be from November right through to next June.
This guide covers everything to sow, plant, and harvest in September across the UK, with cultivar recommendations backed by the RHS Award of Garden Merit (AGM) where available, regional timing adjustments, and practical advice for making the most of the autumn transition.
Regional Timing Guide
September weather varies dramatically across the UK. Southern gardeners typically enjoy mild conditions well into October, while parts of Scotland can see the first ground frosts by late September. Use this table to adjust your sowing and planting dates accordingly.
Region
Average First Frost
September Guidance
South England (London, Kent, Devon)
Late October – mid-November
Full month available for outdoor sowings. Plant bulbs from mid-September.
Midlands (Birmingham, Nottingham)
Mid-October – early November
Complete final sowings by mid-September. Fleece ready for late-month cold snaps.
North England (Yorkshire, Lancashire)
Early–mid October
Prioritise overwintering crops in the first two weeks. Protect salad sowings with cloches.
Scotland (Lowlands)
Late September – mid-October
Sow under cover from mid-September. Focus on hardy overwintering varieties only.
Scotland (Highlands) / Northern Ireland
Mid-September – early October
Outdoor sowing window largely closed. Use cold frames, polytunnels, or cloches.
If you are gardening in the north, a simple sheet of horticultural fleece or a row of cloches extends your effective growing season by two to three weeks. That can make the difference between a successful September sowing and a failed one.
Overwintering Crops to Sow and Plant Now
Overwintering crops are sown or planted in autumn, sit through winter as small plants or dormant bulbs, and then crop weeks ahead of spring-sown equivalents. September is the month to get the foundations in place.
Onion Sets (Autumn Varieties)
Autumn-planted onion sets produce mature bulbs in June — a full month before spring-planted ones. For the best autumn varieties and suppliers, see our guide to the best onion sets for autumn planting. Push each set into well-drained soil with the tip just visible, spacing them 10 cm apart in rows 25 cm apart.
‘Radar’: Exceptionally hardy Japanese variety. Survives the harshest UK winters and produces medium-sized, round bulbs with mild flavour. The most reliable choice for northern gardeners.
‘Senshyu Yellow’: A semi-flat, straw-coloured Japanese onion with good storage qualities. Crops slightly earlier than ‘Radar’ and produces large bulbs in fertile soil.
Plant from mid-September to mid-October. Avoid waterlogged ground — onion sets will rot in standing water. A raised bed with good drainage is ideal. Autumn onion sets and seed garlic are widely stocked by suppliers such as Suttons and Thompson & Morgan, and by larger garden centres, from late summer.
Garlic (Soil Preparation)
Garlic cloves go into the ground from October through to November in most of the UK, but September is the month to prepare. Choose a sunny, well-drained spot and dig in plenty of well-rotted compost or manure now. This gives the organic matter time to integrate with the soil before planting.
Select autumn-planting cultivars such as ‘Solent Wight’ (a reliable softneck bred on the Isle of Wight) or ‘Germidour’ (a French softneck with excellent keeping qualities). Both need a period of cold — known as vernalisation — to develop properly sized bulbs, making autumn planting essential in the UK climate.
When planting time arrives, set individual cloves 5 cm deep and 15 cm apart, pointy end up. In mild southern areas, you can plant garlic from late September; everywhere else, October or November is more reliable.
Broad Beans (Preparation and Early Sowing)
Autumn-sown broad beans crop three to four weeks earlier than spring-sown plants. The classic autumn variety is ‘Aquadulce Claudia’ AGM — bred specifically for overwintering, with excellent cold tolerance and heavy yields of long, well-filled pods.
The main sowing window is November, but September is the time to prepare your bed. Clear spent summer crops, dig the soil over, and incorporate compost. If you are in a mild, sheltered area (south coast, inner city), you can make an early sowing from late October. ‘The Sutton’ AGM is a compact alternative at just 30 cm tall — useful for exposed or windy sites where taller varieties would need staking.
Spring Cabbage
Transplant spring cabbage seedlings (sown in July or August) to their final positions this month. Space them 30 cm apart in firm, well-drained soil. They will form small rosettes through winter and heart up rapidly in March and April, filling the hungry gap when little else is ready to harvest.
If you missed the sowing window, garden centres often sell module-raised spring cabbage plants in September. ‘Durham Early’ and ‘April’ are reliable choices for overwintering.
Final Outdoor Sowings
September is the last realistic month for outdoor sowing in most of the UK. The soil is still warm enough for germination, but you are racing against the shortening days and the first frosts. Choose fast-maturing, cold-hardy varieties and be prepared to cover them with fleece or cloches as temperatures drop.
Lettuce and Salad Leaves
Cold-hardy lettuce varieties sown in early September will provide fresh salad leaves from late October into December — and longer with cloche protection.
‘Winter Density’ AGM: A semi-cos type specifically bred for late-season and overwintering use. Stands well in cold weather and has a crisp, sweet flavour.
‘Chartwell’ AGM: A butterhead with outstanding cold tolerance. Forms neat, compact hearts and performs reliably through autumn.
‘Little Gem’ AGM: Compact cos lettuce that matures quickly. Ideal for small spaces and containers.
Sow short rows every 10 days in early September for a succession of pickings. Once night temperatures regularly fall below 5 °C, cover rows with fleece or move containers under the shelter of a cold frame.
Spinach
September-sown spinach avoids the bolting problems that plague spring sowings, because day length is decreasing rather than increasing. ‘Lazio’ is a vigorous, downy-mildew resistant variety widely recommended for autumn sowing, and ‘Medania’ — which holds an RHS Award of Garden Merit — is a reliably hardy alternative that stands well through a UK winter. Sow directly in rows 30 cm apart, thin seedlings to 15 cm, and start harvesting outer leaves once plants are established.
Spinach is one of the hardiest leafy crops you can grow. Established plants will survive temperatures down to around -10 °C, producing fresh leaves through autumn and picking up again in early spring.
Radish
Radishes are among the fastest crops in the garden — ready in as little as four weeks from sowing. ‘Cherry Belle’ is a reliable round, red variety that performs well in cooler conditions. For something different, try winter radish varieties like ‘Black Spanish Round’ or ‘China Rose’, which are sown in late summer and autumn, grow much larger, and store well through winter.
Sow thinly in rows 15 cm apart and thin to 2-3 cm. Keep the soil moist and harvest promptly; radishes left too long in the ground turn woody and hollow.
Spring Onions
A September sowing of ‘White Lisbon Winter Hardy’ — or the equally hardy ‘Winter White Bunching’, which holds an RHS Award of Garden Merit — will overwinter as small plants and give you an early crop of spring onions next March, well ahead of anything sown in spring. Sow in drills 1 cm deep and 10 cm apart. They need minimal care over winter and tolerate frost without damage.
Pak Choi and Oriental Greens
Pak choi (try the reliable ‘Joi Choi’ or red-leaved ‘Red Choi’), mizuna such as ‘Red Frills’, mibuna and mustard greens actually prefer the cooler, shorter days of autumn. Spring and summer sowings tend to bolt almost immediately, but September sowings grow steadily and produce tender leaves for stir-fries and salads. Sow in rows or scatter-sow in a wide drill, and start picking baby leaves within three to four weeks. Protect from slugs, which are particularly active in damp autumn weather.
Green Manures
Any bed cleared of spent summer crops should be sown with a green manure rather than left bare. Exposed soil loses nutrients through leaching, develops a crust that repels water, and becomes colonised by weeds. Green manures solve all three problems while actively improving your soil.
What to Sow
Field beans (Vicia faba, such as the green-manure variety ‘Wizard’): The best green manure for heavy clay soil. Their deep roots break up compaction, and as legumes they fix atmospheric nitrogen in root nodules, enriching the soil for the next crop. Sow September to November; dig in during March.
Crimson clover (Trifolium incarnatum): Another nitrogen-fixer, with the bonus of striking crimson flower heads in spring that attract pollinators. Sow by mid-September for good establishment. Dig in before flowering or leave for the bees and cut back afterwards.
Phacelia (Phacelia tanacetifolia): Rapid germination and dense, weed-suppressing growth. Not a legume, so it does not fix nitrogen, but it adds excellent biomass and its purple flowers are irresistible to bees and hoverflies. Sow by early September — it is not fully winter-hardy and may be killed by hard frosts, but the dead foliage still protects the soil.
Winter tare (Vicia sativa): A vigorous, nitrogen-fixing legume that overwinters reliably across the UK. Sow September to October. It scrambles rather than grows upright, forming a dense ground cover. Dig in four weeks before you need the bed in spring.
Why It Matters
The RHS recommends green manures as one of the most effective ways to maintain soil fertility without relying on bought-in inputs. Nitrogen-fixing species (field beans, clover, winter tare) capture nitrogen from the air and store it in root nodules. When you dig the plants in, that nitrogen becomes available to your next crop. Non-legumes like phacelia contribute organic matter, improve soil structure, and prevent erosion from heavy autumn and winter rain.
Broadcast the seed over raked soil, tread it in lightly, and water if conditions are dry. Most green manures need no further attention until you dig them in.
Spring Bulb Planting
September is the start of the spring bulb planting season, and getting the right bulbs in early gives them the longest possible establishment period before winter dormancy. For the full rundown — planting depths, spacing, pots and naturalising — see our dedicated guide to the spring bulbs to plant in September. Order bulbs early from suppliers such as Suttons, Thompson & Morgan or Crocus while the choice is widest, and see our buyer’s guide to the best spring-flowering bulbs for the top AGM picks.
Plant Now (September to November)
Daffodils (Narcissus): Plant as early as possible — ideally in September — so roots develop well before the ground cools. Set bulbs at a depth of roughly three times their height (typically 10-15 cm) in any reasonable soil. They naturalise well in grass and under deciduous trees.
Crocuses: Plant 8-10 cm deep in drifts for maximum impact. Species crocuses (Crocus tommasinianus, C. chrysanthus) are excellent for naturalising in lawns. Dutch crocuses give larger, showier flowers in borders and pots.
Hyacinths: Best in pots, window boxes, and border fronts where you can appreciate the scent. Plant 10-12 cm deep. Wear gloves when handling bulbs — hyacinth bulb sap can irritate skin.
Alliums: Ornamental alliums (Allium ‘Purple Sensation’, A. cristophii, A. hollandicum) produce dramatic spherical flower heads in late spring. Plant 10-15 cm deep in well-drained soil. They combine beautifully with perennials and grasses.
Wait Until November: Tulips
Do NOT plant tulip bulbs in September. Tulips should go in from November onwards, when soil temperatures have dropped below 10 °C. Planting earlier risks tulip fire (Botrytis tulipae), a fungal disease that thrives in warmer soil and can devastate an entire planting. Store your tulip bulbs in a cool, dry place and plant them in November or even early December — they are one of the last bulbs to go in and they cope perfectly well with late planting.
Fruit: Planting, Maintenance, and Harvest
Plant Strawberry Runners
September is still a good time to plant strawberry runners, though August is the ideal month. Runners planted now will establish roots through autumn and produce a crop next summer. Plant into well-prepared soil enriched with compost, spacing plants 35-45 cm apart in rows 75 cm apart.
‘Cambridge Favourite’ AGM: The most widely grown garden strawberry in the UK. Mid-season, reliable cropping, and excellent flavour. Tolerates a range of soil types.
‘Florence’ AGM: Late-season, heavy-cropping, and notably disease-resistant. Pairs well with an early or mid-season variety to extend your harvest window.
If you are short on bed space, strawberries grow brilliantly in containers, hanging baskets, and growing bags. Our guide to growing strawberries in pots covers compost choice, feeding schedules, and winter protection.
Autumn-Fruiting Raspberry Maintenance
Autumn-fruiting raspberries are in full production this month. Keep picking every two to three days to encourage continued fruiting well into October.
‘Joan J’ AGM: Spine-free canes with large, dark red berries and outstanding flavour. The most popular autumn-fruiting variety in the UK.
‘Polka’ AGM: Heavy-cropping with good disease resistance. Fruits slightly earlier than ‘Joan J’ and performs well in containers.
Once fruiting finishes (usually by late October or after the first hard frost), leave the canes standing until February. Then cut them all to ground level — autumn-fruiting raspberries produce fruit on the current year’s growth, so there are no old canes to preserve.
Harvest Apples, Pears, and Plums
September is peak harvest time for tree fruit. Early and mid-season apple varieties (‘Discovery’, ‘James Grieve’, ‘Worcester Pearmain’) are ready from early September. Mid-season pears (‘Conference’, ‘Williams’ Bon Chretien’) should be picked while still firm and ripened indoors. Plums and damsons are at their best in the first two weeks of September — ‘Victoria’ is the classic garden plum and will not hang on the tree much beyond mid-month.
To test whether an apple is ready, cup the fruit gently and twist. If it comes away easily with the stalk intact, it is ripe. If you have to tug, leave it another week.
What to Harvest in September
September is a month of abundance. Summer crops are still producing alongside the first of the autumn harvests, and the kitchen can feel overwhelmed. Here is what should be coming off the plot this month.
Vegetables
Tomatoes: Outdoor tomatoes need to be harvested before the first frost. Pick any remaining green tomatoes and ripen them indoors in a paper bag with a banana — the ethylene gas speeds ripening.
Courgettes: Still producing prolifically in early September. Pick regularly at 10-15 cm to keep the plants going.
Runner beans and French beans: The final pickings of the season. Harvest every two to three days and freeze any surplus (blanch for two minutes, cool in iced water, then bag flat).
Sweetcorn: Ready when the tassels turn brown and a pressed kernel releases milky sap. Cook within hours of picking for the sweetest flavour.
Beetroot: Pull roots at golf-ball to tennis-ball size. ‘Boltardy’ AGM and ‘Pablo’ AGM both store well in a cool, dark place or in boxes of damp sand.
Carrots: Lift main-crop carrots before the soil becomes waterlogged. ‘Flyaway’ AGM and ‘Nairobi’ AGM store well in boxes of sand or in the fridge.
Fruit
Apples and pears: As detailed above — pick early and mid-season varieties this month.
Plums and damsons: Harvest promptly; overripe plums attract wasps and split on the tree.
Blackberries: Peak season. Pick when fully black and slightly soft to the touch. They freeze well — spread on a tray in a single layer, freeze, then transfer to bags.
Autumn raspberries: Continuous harvest through the month from ‘Joan J’ AGM and ‘Polka’ AGM.
Storage Tips
Root vegetables (carrots, beetroot, parsnips): Store in boxes of damp sand in a cool, dark shed or garage. They will keep for months.
Apples: Wrap individually in newspaper and store in a single layer in trays. Keep in a cool, frost-free place. Check regularly and remove any that show signs of rot.
Freezing: Beans, courgettes (sliced), berries, and herbs (in ice-cube trays with water or oil) all freeze well.
Preserving: Green tomato chutney, blackberry jam, and apple butter are excellent ways to use up gluts.
Container Growing in September
Containers are particularly valuable in September because you can move them under cover as temperatures drop, extending your growing season by weeks.
Winter Salads in Containers
A 30 cm pot or window box is all you need for a steady supply of autumn and winter salad leaves. Sow ‘Winter Density’ AGM lettuce, spinach, or a cut-and-come-again salad mix. Position in a sheltered, sunny spot and water regularly — but reduce watering as temperatures fall, as waterlogged compost in cold weather causes root rot.
Once night temperatures regularly dip below 5 °C, move pots against a south-facing wall, into a porch, or under a cold frame. Even a sheet of fleece draped over the pot makes a significant difference.
Herb Pot Maintenance Before Frost
Tender herbs need attention this month. Basil will not survive the first frost, so harvest all remaining leaves and make pesto or freeze in ice-cube trays. Bring pots of tender herbs (basil, lemon verbena, scented pelargoniums) indoors to a bright windowsill.
Hardy herbs — rosemary, thyme, sage, bay — can stay outdoors but benefit from a tidy-up. Remove dead or straggly growth, reduce watering, and ensure pots have adequate drainage. Waterlogging kills more Mediterranean herbs in winter than cold does.
Protect Tender Plants
Container-grown citrus, olive trees, and half-hardy perennials should be moved to a frost-free greenhouse, conservatory, or porch before the first frost. If you cannot move them, wrap pots in bubble wrap to insulate the roots and drape fleece over the foliage on frosty nights. Raise pots onto feet or bricks to prevent waterlogging.
What NOT to Plant in September
Knowing when it is too late to sow is just as valuable as knowing what to plant. These crops are off the table for September:
Tomatoes, peppers, and chillies: These tender crops need sustained warmth and long days. Any seedlings started now would be killed by frost long before producing fruit. Enjoy the last of this year’s crop and plan for next April’s sowings.
Courgettes and squash from seed: Far too late. They need months of warm growing weather. Harvest what you have and add spent plants to the compost heap.
Tulip bulbs: Wait until November. Planting tulips in warm September soil significantly increases the risk of tulip fire (Botrytis tulipae). Store bulbs in a cool, dry place until soil temperatures drop below 10 °C.
Most bedding plants: Summer bedding (petunias, marigolds, begonias) is finishing, not starting. Clear spent bedding and replace with winter-flowering pansies, violas, or cyclamen if you want colour through the colder months.
Sweetcorn: Needs long, warm days and months to maturity. The sowing window closed in May.
Main-crop potatoes: Far too late for outdoor planting. If you want a very late crop, try a few tubers in bags kept in a frost-free greenhouse, but expectations should be modest.
Autumn Garden Maintenance
September is one of the best months for tackling maintenance jobs that keep your garden healthy and productive. The soil is workable, the weather is usually cooperative, and there is less competition from active sowing and harvesting.
Lawn Care
September is the single best month for lawn renovation in the UK. The soil is warm enough for grass seed to germinate, and autumn rain keeps it moist without you lifting a finger. Our full autumn lawn care guide walks through the whole renovation — scarifying, aerating, overseeding and feeding — step by step.
Scarify: Rake out thatch (dead grass and moss) with a spring-tine rake or powered scarifier. This improves air circulation and allows water and nutrients to reach the roots.
Aerate: Push a garden fork or hollow-tine aerator into the lawn at 15 cm intervals to relieve compaction. Brush sharp sand into the holes on heavy clay soils.
Overseed: Scatter grass seed into thin or bare patches. Keep the area moist until the seed has germinated (typically 7-14 days in September). Apply an autumn lawn feed — high in potassium to toughen the grass for winter, not nitrogen which would promote soft growth. Autumn feeds are stocked by B&Q, Crocus and the main online retailers from late summer.
Compost Heaps
September generates a surge of compostable material: spent crops, prunings, and the first fallen leaves. Turn your compost heap to introduce oxygen and speed up decomposition. If the heap is dry, water it as you turn. Shred woody material before adding it — thick stems decompose slowly if left whole.
Start a separate leaf-mould bin for fallen leaves. Collect leaves, pack them into a wire-mesh bin or black bin bags (pierce a few holes), dampen, and leave for 12-24 months. The resulting leaf mould is one of the finest soil conditioners available and costs nothing. For more on composting methods, see our guide to compost for container gardening.
Greenhouse Cleaning
Once summer crops are cleared from the greenhouse, give it a thorough clean before winter. Wash glass or polycarbonate panels inside and out with warm, soapy water to maximise light transmission through the shorter days. Scrub staging, remove algae from paths, and check for broken panes or gaps in seals. Good hygiene reduces overwintering pest and disease populations.
Netting Fruit Bushes
Birds are attracted to late-ripening fruit — blackberries, autumn raspberries, and late apples. Net fruit bushes and cages to protect your harvest. Use bird-friendly netting with a mesh size no larger than 20 mm to prevent birds becoming trapped.
Frequently Asked Questions
Can I still sow lettuce outdoors in September?
Yes, but stick to cold-hardy varieties and sow in the first half of the month. ‘Winter Density’ AGM and ‘Chartwell’ AGM are bred for late-season growing and tolerate frost. In northern regions, sow under cloches or in a cold frame for the best results. You can continue sowing lettuce under cover well into October.
When should I plant garlic in the UK?
Most gardeners plant garlic from October to November. September is too early in most areas — the cloves may sprout prematurely and then be damaged by winter cold. Use September to prepare the bed: clear weeds, improve drainage, and dig in compost. In very mild, southern locations, planting from late September is possible but not necessary.
Is September too late to plant strawberry runners?
September is acceptable but not ideal — August is the best month. Runners planted in September will still establish roots before winter and produce a crop next summer, but the yield may be slightly lower than August-planted ones. Choose vigorous AGM varieties like ‘Cambridge Favourite’ AGM or ‘Florence’ AGM for the best chance of success.
Why should I wait until November to plant tulip bulbs?
Tulip fire (Botrytis tulipae) is a fungal disease that infects bulbs in warm soil. By waiting until November, when soil temperatures have dropped below 10 °C, you dramatically reduce infection risk. Tulips tolerate very late planting — even December works — so there is no rush. Daffodils, crocuses, and hyacinths, by contrast, benefit from earlier planting and can go in from September.
What is the best green manure for clay soil?
Field beans (Vicia faba) are the top choice for heavy clay. Their deep tap roots penetrate and break up compacted clay, improving drainage and structure. As legumes, they also fix nitrogen. Sow from September to November, then dig in the following March, at least four weeks before you plan to sow or plant into that bed.
How do I protect container plants from early frost?
Move tender plants (citrus, olive trees, half-hardy perennials) to a frost-free space — a greenhouse, conservatory, or porch. For pots that cannot be moved, wrap the container in bubble wrap or hessian to insulate the roots, raise it onto pot feet for drainage, and drape horticultural fleece over the foliage on frosty nights. Hardy herbs like rosemary and thyme survive outdoors in most of the UK but need good drainage — waterlogging is more dangerous than cold.
Can I still sow green manures in October if I miss September?
Yes. Field beans and winter tare can be sown right through to November and will overwinter successfully. Crimson clover is best sown by mid-September, but phacelia can go in until early October in mild areas (though it may be killed by hard frost — the dead top growth still protects the soil). The key is not to leave beds bare over winter.
What should I do with green tomatoes at the end of September?
Pick all remaining green tomatoes before the first frost. To ripen them, place in a paper bag with a ripe banana — the ethylene gas encourages ripening. Alternatively, make green tomato chutney, which is an excellent way to use up large quantities. Do not leave tomato plants in the ground over winter; clear them, dispose of any blighted foliage (do not compost it), and sow a green manure on the cleared bed.
What Next
Keep your garden productive year-round. September is just one chapter in the planting calendar. Use these guides to plan ahead and make the most of every month:
