Start with what pollinators actually need

Even a balcony three floors up is a genuine pit stop for bees, hoverflies and butterflies. Cities are warmer than the surrounding countryside, and nectar sources can be thin on the ground, so a few well-chosen pots do real work. The goal is simple: flowers offering nectar and pollen from early spring right through to the first frosts.

Before you buy anything, watch your space for a day. Most nectar-rich plants want at least six hours of direct sun, so a south, south-east or west-facing balcony is ideal. If yours is shaded, don't despair — you can still grow ivy, deadnettle, foxgloves and several shade-tolerant herbs. Wind is the other consideration on upper floors, so sheltering pots behind a railing, against a wall or in a corner will make a noticeable difference to how well plants establish.

Nectar-rich flowers that thrive in pots

You don't need dozens of plants. Four or five generous containers, planted well, will outperform a crowded row of tiny pots. Aim for a mix that flowers at different times, and choose compact varieties suited to container life.

• Lavender — 'Hidcote' or 'Munstead' are hardier than French lavender and adored by bumblebees. It needs sharp drainage, so add grit to the compost.
• Catmint (Nepeta) — flowers for months if you shear it back after the first flush. Let it flop a little; bees don't mind.
• Wallflower (Erysimum) — 'Bowles's Mauve' can flower almost year-round in a sheltered spot, filling the gaps when little else is open.
• Oregano, marjoram and thyme — culinary herbs are some of the best pollinator plants you can grow, and they cope with dry, shallow pots.
• Salvia, scabious, yarrow and sedum — late-summer stalwarts that carry bees and butterflies into autumn.

One warning worth heeding: skip double-flowered bedding. Petunias, begonias, busy Lizzies and most fancy double blooms have had their nectar and accessible pollen bred out of them. They look cheerful and feed nothing.

Choose native and near-native species where you can

British insects evolved alongside British plants, so natives are usually the easiest win. Foxgloves, purple loosestrife in a large pot, wild marjoram, field scabious, knapweed, cowslip and bird's foot trefoil all work in containers and support specialist species as well as generalists.

That said, a strict natives-only rule isn't necessary. Dwarf buddleia, verbena, agastache and single dahlias are excellent value and will be buzzing within minutes of opening. For early spring, layer bulbs into your pots in autumn — crocus, grape hyacinth and snowdrops give hungry queens something to find in February and March, long before the summer flowers arrive. Plant them below your perennials in the same pot and they'll emerge, flower and retreat while the plants above are still waking up.

A tiny water dish changes everything

Water is the single most overlooked element of a wildlife balcony, and it costs almost nothing. Fill a shallow saucer — around two to four centimetres deep — and add pebbles, marbles or broken crocks so insects have somewhere to land and drink without falling in. Bees drown surprisingly easily in open water.

• Top it up every other day in warm weather and scrub it weekly to keep it fresh.
• Place it among your pots rather than in blazing midday sun, so it stays cool and evaporates more slowly.
• Add a second tray of damp sand for butterflies, which take minerals from wet ground rather than drinking freely.
• If you hang a bird bath, keep it well above cat height and refresh it daily.

Shelter, nesting and overwintering spots

Flowers feed insects; cover keeps them alive. A few small additions turn a balcony from a café into a home.

• Hang a solitary bee hotel facing south or east, at least a metre off the ground, and keep it dry. Clean it or replace the tubes every couple of years.
• Tie a bundle of hollow bamboo canes together and tuck it into a corner — simple, cheap and quickly occupied.
• Stack a few short lengths of log or a pot of loose twigs behind your containers for beetles, spiders and hibernating ladybirds.
• Leave seedheads and hollow stems standing over winter, then cut back in late spring rather than autumn.
• Grow ivy in a pot trained up a wall. Its late flowers are a lifeline for bees in October, and its berries feed birds in winter.

Small-space practicalities that make it last

Bigger pots are easier than small ones: they hold moisture, stay cooler and let roots spread. Aim for at least thirty centimetres across for perennials, and use lightweight plastic or fibreglass containers rather than heavy terracotta if weight is a concern — a balcony has a load limit, and compost is heavy when wet.

Use peat-free compost mixed with grit or perlite, and top it with a gravel mulch to slow evaporation and deter vine weevil. Water in the morning, check pots twice on hot days, and feed flowering containers weekly with a tomato-type feed from midsummer — but don't overfeed, as too much nitrogen gives you leaves instead of flowers. Never use pesticides; a blast of water deals with most aphids, and a little nibbling is a sign the garden is working. Finally, check your lease or tenancy before fixing anything to the wall or railing, and move pots to a sheltered spot when gales are forecast.

Start with one sunlit corner, one water dish and a couple of lavender plants. By July you'll be counting bees before breakfast.