What to Grow on a Balcony in Autumn (UK)

Autumn balcony growing splits into three jobs. First, keep your hardy herbs cropping - most of the perennial kitchen herbs shrug off a British autumn. Second, sow and harvest cool-season salads and leafy greens that actively prefer the shorter, cooler days. Third, get overwintering crops in the ground now - broad beans, garlic and onions you plant in autumn to harvest weeks earlier next year.

A balcony changes the maths in two ways. The good news: walls radiate stored heat, and being a few floors up lifts you clear of the frost pockets that settle in gardens, so a city balcony often runs a degree or two milder than ground level. The catch: container roots sit above ground in cold, moving air, so they chill far faster than roots in open soil. Wind is the real enemy up high, not cold alone. Choose tough crops, group your pots, and you can keep a balcony productive well into winter.

South-facing is the best aspect for autumn growing. Which way the balcony faces matters more in autumn than in any other season, because the sun sits low and every hour of direct light counts. South-facing balconies are the autumn winners: low sun reaches deep under the balcony above and warms the back wall, so salads keep growing into November and a mini greenhouse earns its place. West-facing balconies get warm afternoon light but also take the brunt of the UK's prevailing south-westerly gales, so windbreaks and heavy, low pots come first.

East-facing balconies get gentle morning sun, with one autumn catch: frosted leaves that thaw fast in early sun suffer more damage than leaves that thaw slowly, so throw fleece over salads on clear, cold nights and lift it mid-morning. North-facing balconies get little or no direct sun from October to February. Sow leafy crops by early September so they are established before the light fails, lean on garlic, onion sets and broad beans (which sit quietly through winter whatever the light), and plan to move cutting crops indoors early. Our north-facing balcony guide goes deeper on low-light crops.

Most woody and perennial herbs are genuinely hardy and stay outside all winter. Thyme, sage, winter savory and bay keep their leaves; chives and mint die back to the compost and return in spring; rosemary stays evergreen and cropping as long as its roots never sit waterlogged. Parsley is a biennial (a plant that grows one year and flowers the next), so a plant sown in summer keeps giving leaves through a mild winter, especially under a cloche - a clear cover that traps warmth over a plant.

Cut woody herbs back lightly now rather than hard - save the heavy pruning for spring. Move pots to the most sheltered corner you have, and top the compost with a little grit or bark to insulate the roots. Coriander is the autumn surprise: sown in early September it crops for weeks in cool weather without the summer rush to bolt. The one herb that will not take it is basil - it collapses at the first cold night, so bring it indoors to a bright windowsill before the temperature drops.

Autumn is prime time for cut-and-come-again leaves (crops where you pick the outer leaves and the plant keeps regrowing from the centre). They germinate fast in warm September compost, then crop slowly through the cold. The hardiest of all is lamb's lettuce, also sold as corn salad - it survives hard frost and keeps producing mild, nutty rosettes.

Alongside it, sow winter lettuce ('Winter Density', 'Arctic King' and 'Valdor' are bred for the cold), peppery mizuna and mustard greens like 'Red Giant', land cress (a hardy stand-in for watercress), winter purslane, overwintering spinach ('Giant Winter') and Swiss chard, whose coloured stems earn their space. Sow a small pinch every two or three weeks into pots or window boxes rather than all at once, harvest the outer leaves, and a couple of containers will keep a household in salad through autumn. A cloche or a sheet of horticultural fleece (a light fabric that lifts the temperature a couple of degrees) speeds growth and keeps the leaves clean.

Pot depth is the constraint most balcony growers hit first. Lamb's lettuce is the hardiest salad in the table. Salads root shallowly and crop in a window box; alliums and beans need real depth. Timings below are for southern and central England - add a week or two in the north and Scotland.

The pattern to notice: anything you eat this side of Christmas has to be sown by mid-September, while everything planted in October and November is an investment in next spring. A balcony that misses the September sowing window can still be fully planted with alliums and beans.

Yes - and some crops only work if you sow them now. Overwintering sowings sit through the cold and race away in spring, cropping weeks ahead of anything you plant in March. On a balcony they also keep your pots earning their keep over winter.

Sow hardy broad beans - the variety 'Aquadulce Claudia' is the classic autumn choice - in November for a May crop. Plant garlic now: cloves need a cold spell to split into a bulb, a process called vernalization, so autumn planting gives fatter heads than spring. Push in overwintering onion sets ('Radar', 'Senshyu Yellow', 'Electric') and autumn-sown hardy peas ('Meteor', 'Douce Provence'), and plant out spring cabbage from a summer sowing or bought plug plants by early October. Garlic wants a pot at least 25cm deep with cloves 15cm apart and their tips 2.5cm below the surface, according to the RHS garlic growing guide; onions take the same depth, which gives the roots room to anchor against winter wind.

The first autumn frost reaches most of the UK between late October and late November, earlier in Scotland and northern hills - the Met Office keeps regional frost guidance worth checking against your postcode. Before it arrives, move anything tender - basil, tender perennials, young citrus, pelargoniums - indoors or into a mini greenhouse.

For the hardy pots that stay out, the danger is rarely the air temperature; it is frozen, waterlogged compost rotting the roots. Raise every pot onto feet or bricks so water drains freely, and wrap the pot itself - not the plant - in bubble wrap or hessian, because a container freezes solid in a way open ground never does. Cluster pots together against a warm wall so they shelter each other, throw fleece over salad crops on the coldest nights, and use a cloche to keep winter leaves cropping. Grouping by hardiness makes the nightly frost routine a two-minute job rather than a chore.

The container matters as much as the crop once the frosts start. Cheap terracotta absorbs water, freezes and flakes or splits; the RHS container maintenance guide recommends pots sold as frost-proof, which is a stronger rating than frost-resistant, or switching to plastic, fibreglass or wood. Glazed pots with a narrow neck are the worst offenders: ice expands upward and outward and cracks the rim.

Frost-proof is the label to look for. Take saucers away for the winter so pots never stand in water, stand them on pot feet, and hold off watering when a frost is forecast. On a balcony there is one extra consideration: compost that is soaked through by autumn rain weighs far more than the same compost dry, so a run of large deep pots for garlic and beans adds real load. Keep the heaviest containers close to the wall rather than at the outer edge, and read our guide to how much weight a balcony can hold before you add a row of big tubs.

After the autumn equinox in late September, daylight shortens quickly. By November a UK balcony gets too little light for productive leafy growth and almost none for fruiting crops, and low-angle sun barely clears neighbouring buildings. The tell-tale signs are plants that pale and stretch, leaning and reaching toward the window - a stretching for light called etiolation.

That is the moment to move the crops you want to keep cutting indoors under a grow light. A full-spectrum LED on a windowsill keeps a pot of basil, coriander or salad leaves growing right through winter, and a countertop hydroponic smart garden takes over entirely when the balcony goes dark. If you are new to artificial light, our guide to grow light spectrum explained simply covers what 'full spectrum' actually means and how close to hang the light. Autumn is the natural handover from balcony to windowsill - plan it before the clocks change, not after your herbs have already collapsed.

Three habits change as the season turns. Water less. Growth slows and evaporation drops, so pots stay wet for days - cold, sodden compost is what kills overwintering crops, not the frost. Water in the morning so the roots are not sitting soaked overnight, and let the top of the compost dry between waterings - a soil moisture sensor takes the guesswork out of deep pots, where the surface dries long before the roots do. Our balcony watering guide covers dialling back an automatic system for the cooler months.

Break the wind. On an exposed balcony, autumn gales scorch leaves and topple tall pots faster than any frost. Move containers into a sheltered corner, add a screen or trellis as a windbreak, and stand top-heavy pots on the floor rather than a railing. Stop feeding. Most crops need no feed now - late nitrogen forces soft growth that frost destroys - so put the fertiliser away until spring. Finally, sweep up fallen leaves that collect on the compost, where they harbour slugs and rot.

Five pots are enough to crop from September to June. A small balcony does not need a dozen containers to stay productive. Five pots, planted in September and October, cover salad, herbs and a spring harvest:

1. A long trough of lamb's lettuce and land cress, sown in September - the hardiest pairing, cropping right through winter with no protection.
2. A 30cm pot of mizuna and mustard, resown every three weeks until mid-September for fast, peppery leaves into November.
3. A herb pot of thyme, parsley and chives in free-draining compost, pushed into the most sheltered corner.
4. A deep pot of garlic, at least 25cm deep; a 40cm-wide pot fits five or six cloves at 15cm spacing.
5. A deep tub of broad beans, sown in November for pods in May, with a few short canes and string to stop the plants rocking in the wind.

Garlic planted in October is ready in June or July. The first two pots feed you this autumn; the last two fill the gap next spring, when summer crops have not yet started. Our guide to how much food you can grow on a balcony puts realistic numbers on what a setup this size yields, and vertical growing adds salad space without using more floor.

• Sowing salads too late. Leaves sown in late October germinate slowly and sit as seedlings until March. Get salad sowings done by mid-September, or sow under cover.
• Leaving saucers under pots. Rainwater collects, the bottom of the root ball sits wet, and a frost freezes it solid.
• Feeding into autumn. Late nitrogen pushes out soft leaves that the first frost blackens.
• Trusting cheap terracotta. A pot that cracks in January takes its crop with it.
• Waiting for basil to show damage. Basil is killed by the first frost. By the time the leaves blacken, the plant is gone - move it indoors when nights fall below about 10°C.
• Ignoring the wind. On upper floors, wind dries and tears leaves faster than cold does. Shelter beats insulation.