Why a pot is a perfectly good meadow

You do not need a garden to feed pollinators. A windowsill, a doorstep or a balcony barely a metre wide can supply bees and butterflies with a steady supply of nectar and pollen from spring right through to the first frosts. Wildflowers are often assumed to be meadow plants that need space and poor soil, but many of our best pollinator plants are compact, tolerant of confinement and perfectly happy in a 10-litre pot. What they cannot cope with is competition, drought and rich, soupy compost — and all three are easy to avoid once you know how.

The other advantage of containers is control. You can move pots into shelter on a windy balcony, raise them out of reach of slugs, and grow exactly the mix of flowers that suits the insects visiting your patch. Treat a row of pots as a miniature meadow and it will behave like one.

Choosing a compact wildflower mix

Avoid generic "bee bomb" mixes that contain tall, thuggish species such as teasel, hogweed or common knapweed, which will sprawl and flop in a pot. Look instead for short, clump-forming natives and near-natives. Reliable choices include birds-foot trefoil, selfheal, wild marjoram, salad burnet, yarrow, oxeye daisy, field scabious and betony. For annual colour, cornflower, corn marigold, corn poppy and chamomile are hard to beat and will self-seed in a pot for a year or two.

Try to include at least one plant from each of these groups:

• Early nectar — lungwort, cowslip, white dead-nettle, flowering from March.
• Summer bulk — marjoram, betony, knapweed, catmint, flowering June to August.
• Late flowers — field scabious, viper's-bugloss and devil's-bit scabious, feeding butterflies into September.
• Larval food — a little bird's-foot trefoil for common blue butterflies, and nettles in a hidden corner for red admirals and peacocks.

Pots, compost and drainage

Size matters more than style. Aim for pots of at least 30 cm across and 10 to 15 litres for perennials, and 20 cm for annuals. Terracotta dries out faster than glazed or plastic, so line the inside of terracotta with a thin layer of newspaper if you use it. Every pot needs a drainage hole — no exceptions — and a 2 cm layer of crocks or gravel in the base stops the hole silting up.

Use a peat-free, soil-based compost for perennials, mixed with about 20 per cent horticultural grit or sharp sand. Peat-free multipurpose is fine for annuals, again with grit added. Do not enrich the compost with fertiliser or manure: wildflowers flower best on lean ground, and rich compost simply produces soft leaves and few blooms. A scattering of mycorrhizal fungi at planting does no harm and helps roots establish.

Sowing and getting them going

Annuals are best sown directly into the pot in late April or early May, scattering seed thinly — one seed per square centimetre is plenty. Cover with a bare 2 to 3 mm of compost and water gently with a fine rose. Perennials can be sown in autumn for natural cold stratification, or bought as small plug plants in spring and planted out after the last frost.

Thin ruthlessly. Crowded seedlings compete for water, sulk and produce weedy, flowerless plants. Once annuals are 5 cm tall, pull out the weakest until the remaining plants are 10 to 15 cm apart. Keep the surface damp, not soaking, for the first three weeks, then ease off and let the roots search for water.

Watering through dry spells

This is where most container meadows fail. Pots dry out far faster than borders, and a wilting wildflower stops producing nectar within days. Water deeply rather than little and often: a good soak every two or three days in hot weather, ideally in the early morning or evening, until water runs out of the base. A 5 cm mulch of gravel or bark over the compost surface cuts evaporation dramatically and keeps the roots cool.

Stand pots on saucers or trays in July and August, and use rainwater from a butt where you can — it is softer and free. Group pots closely together; they shade one another and create a slightly humid microclimate that suits both plants and insects. If you are going away, move pots into shade and stand them in a tray of water no deeper than 2 cm.

Keeping the season going

Deadhead annuals regularly to keep them flowering, but leave the last seedheads of the year standing for birds and for next year's seedlings. Cut perennials back by a third after their first flush in midsummer and many will flower again in early autumn. Top up compost each spring, dividing congested clumps every two or three years.

Never use insecticides or slug pellets on or near pollinator pots. Hand-pick slugs after rain, and accept a few nibbled leaves as the price of a living garden. Beyond that, the work is minimal: water, deadhead, and watch. A balcony of wildflowers can support dozens of bee species across a season, and it costs little more than a few packets of seed and a bag of peat-free compost.